Three ESP8266 OLED Projects: Bitcoin Ticker, Analog NTP Clock & Flip Clock — All Running on the Same Tiny Integrated Board

The NodeMCU ESP8266 with integrated 0.96" OLED display is one of the most quietly capable hobbyist dev boards on the market: a full WiFi microcontroller, a crisp SSD1306 screen, and four mounting holes — all soldered together as a single piece for less than the price of lunch. Below are three of our favorite weekend projects that turn that little board into a desk-worthy gadget. Each one is a single-file Arduino sketch, fully open-source under the MIT license, and ships with the full source code below — copy, flash, and you're done. Get Parts: NodeMCU ESP8266 + Integrated 0.96" OLED

Project 1 — ESP8266 Bitcoin Ticker

A live BTC dashboard driven from CoinGecko's free public API. The headline price is rendered in big custom 7-segment glyphs that flip in odometer-style only on the digits that actually changed. A multi-feed RSS news scroll periodically slides in from the right with the latest Bitcoin headlines from NewsBTC, Bitcoin Magazine, and Decrypt. Below the price, a stats panel rotates every 25 seconds through market cap, 24h volume, 24h low/high, dollar change, and a halving countdown. An NTP-synced clock with full date and AM/PM lives along the bottom.

Because the ESP8266 only has one core, the sketch carefully gates every blocking HTTPS fetch to idle moments when the top row is in the static-ticker state — so the unavoidable freeze always lands in a visual lull instead of stuttering an active animation. The same firmware can ticker Ethereum, Solana, Dogecoin, or any of CoinGecko's 10,000+ coins with a one-line change to the API URL.

Features:

• Live BTC price from CoinGecko's free API, refreshed every 60 seconds — no API key required
• Custom 7-segment glyph renderer with a hand-tuned "$" silhouette to match
• Per-digit odometer flip animation — only the digits that actually changed flip
• Direction-aware flip — price up, new digits arrive from below; price down, from above
• Up/down arrow + edge-pulse brackets that flash on every successful API fetch
• Rotating stats panels: market cap & volume, 24h low/high, 24h dollar change, halving countdown
• Multi-feed RSS news scroll — NewsBTC + Bitcoin Magazine + Decrypt in one rotation
• HTML entity & UTF-8 fold-down so accented characters and curly quotes render cleanly
• Reverse-video source badges so you can tell at a glance which feed the headline came from
• Live WiFi signal-strength bars driven by RSSI
• NTP-synced clock with full date, automatic DST handling via POSIX TZ strings
• Coin-agnostic firmware — one-line change to ticker any CoinGecko-listed coin
• Smart freeze-gating — HTTPS fetches only run during idle visual moments to hide the single-core stall
  

btc_ticker_esp8266.ino

// ============================================================================= // Bitcoin Ticker — ESP8266 + integrated 0.96" OLED // Copyright (c) 2026 eElectronicParts.com // // Licensed under the MIT License (see bottom of file for full text). // // You are free to use, modify, and redistribute this code, including in // commercial projects. If you share a modified version publicly (blog post, // YouTube, GitHub, Instructables, forum), a link back to the original is // appreciated but not required: // // Original project: https://www.eelectronicparts.com // ============================================================================= // Live Bitcoin price ticker with animated 7-segment digits, scrolling RSS // news headlines, rotating stats panels, and an NTP-synced clock — all // driven from CoinGecko's free public API on a 128x64 SSD1306 OLED. // // Hardware: NodeMCU ESP8266 with integrated 0.96" OLED (HW-364A-style). // I2C is hardwired on the PCB: SDA=GPIO14 (D6), SCL=GPIO12 (D5), // address 0x3C. // // Single-core notes: // The ESP8266 only has one core, so blocking HTTPS fetches MUST be gated // to idle visual moments. fetchPrice() and fetchFeed() only run while the // top row is in the static-ticker state — never during an active scroll // or flip animation — so the inevitable freeze lands in a visual lull // instead of stuttering an animation. // ============================================================================= #include [[ESP8266WiFi.h]] #include [[ESP8266HTTPClient.h]] #include [[WiFiClientSecure.h]] #include [[Wire.h]] #include [[Adafruit_GFX.h]] #include [[Adafruit_SSD1306.h]] #include [[ArduinoJson.h]] #include [[time.h]] #include [[math.h]] #define FIRMWARE_VERSION "1.4" // ---------------- USER CONFIG ---------------- const char* MY_WIFI_SSID = "YourWiFiNameHere"; const char* MY_WIFI_PASS = "YourWiFiPasswordHere"; // POSIX TZ string — C library applies DST automatically via localtime_r. // M3.2.0,M11.1.0 = US rule (DST: 2nd Sun Mar → 1st Sun Nov). const char* TIMEZONE = "CST6CDT,M3.2.0,M11.1.0"; // Central [[-- default // const char* TIMEZONE = "EST5EDT,M3.2.0,M11.1.0"; // Eastern // const char* TIMEZONE = "MST7MDT,M3.2.0,M11.1.0"; // Mountain // const char* TIMEZONE = "PST8PDT,M3.2.0,M11.1.0"; // Pacific // const char* TIMEZONE = "MST7"; // Arizona (no DST) // const char* TIMEZONE = "HST10"; // Hawaii (no DST) // const char* TIMEZONE = "AKST9AKDT,M3.2.0,M11.1.0"; // Alaska // const char* TIMEZONE = "UTC0"; // UTC const char* NTP_SERVER_1 = "pool.ntp.org"; const char* NTP_SERVER_2 = "time.nist.gov"; const uint8_t OLED_SDA_PIN = 14; const uint8_t OLED_SCL_PIN = 12; const uint8_t OLED_ADDR = 0x3C; // CoinGecko's public tier caches 1–5 min and rate-limits ~5-15/min per IP. // Fetching faster than ~2 min = duplicate data + 429s. Demo API key // (free) bumps it down to 30–60 s; set COINGECKO_API_KEY to use one. const unsigned long PRICE_FETCH_MS = 120UL * 1000UL; // 2 min const unsigned long RSS_REFRESH_MIN = 15; // full cycle const int HEADLINES_PER_FEED = 1; const char* COINGECKO_API_KEY = ""; // "" = keyless // Halving target — adjust if you want block-height-derived precision. const int HALVING_YEAR = 2028; const int HALVING_MONTH = 4; const int HALVING_DAY = 17; // ---------------- RSS FEEDS ---------------- // Add or remove entries freely; the rest of the pipeline auto-sizes. // Feeds fetch round-robin, one per (RSS_REFRESH_MIN / N_FEEDS) minutes, // so each feed refreshes every RSS_REFRESH_MIN end-to-end. Prefixes // render as the inverted source badge on screen — keep them short // (6–8 chars fits cleanly on a 128 px row without eating the headline). struct RssFeed { const char* url; const char* prefix; }; const RssFeed RSS_FEEDS[] = { { "https://www.newsbtc.com/feed/", "NewsBTC" }, { "https://bitcoinmagazine.com/feed", "BitMag" }, { "https://decrypt.co/feed", "Decrypt" }, }; const size_t RSS_FEED_COUNT = sizeof(RSS_FEEDS) / sizeof(RSS_FEEDS[0]); // ---------------- DISPLAY ---------------- const int16_t SCREEN_WIDTH = 128; const int16_t SCREEN_HEIGHT = 64; Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1); // ---------------- TIMING ---------------- const unsigned long DISPLAY_MS = 1000; const unsigned long SCROLL_FRAME_MS = 50; const unsigned long ANIM_FRAME_MS = 30; // ~33 fps const unsigned long TOP_STATIC_SEC = 60; // ticker dwell before news const unsigned long STATS_FLIP_SEC = 25; const unsigned long STATS_FLIP_ANIM_MS = 500; const unsigned long BLINK_MS = 1200; const int BLINK_COUNT = 3; const float SLIDE_OUT_PXS = 40.0f; const float SCROLL_SPEED_PXS = 30.0f; const unsigned long NEWS_DWELL_MS = 1500; const int16_t ROW1_H = 8; const float SLIDE_IN_PXS = 28.0f; const unsigned long PRICE_ANIM_MS = 600; const unsigned long ARROW_HOLD_MS = 2000; const unsigned long PULSE_IN_MS = 200; const unsigned long PULSE_OUT_MS = 200; const unsigned long PULSE_TOTAL_MS = PULSE_IN_MS + PULSE_OUT_MS; // ---------------- STATE ---------------- float btcPrice = 0.0f; float btcChange24h = 0.0f; float btcMarketCap = 0.0f; float btcVolume24h = 0.0f; bool haveData = false; float btcPriceFrom = 0.0f; unsigned long priceAnimStart = 0; int8_t priceAnimDir = 0; // +1 = up (slide up), -1 = down (slide down) unsigned long pulseStart = 0; // News: feedHeadlines[i] holds the latest headline(s) for RSS_FEEDS[i], // already formatted with STX/ETX sentinels around the prefix. newsText // is the concatenation of all non-empty slots, rebuilt on every update. String feedHeadlines[RSS_FEED_COUNT]; String newsText; uint16_t newsTextW = 0; bool hasNews = false; uint8_t nextFeedIdx = 0; // round-robin cursor for fetch unsigned long nextFeedFetch = 0; // millis target for next feed attempt unsigned long nextPriceFetch = 0; enum TopRowState { STATIC_TICKER, TICKER_BLINKING, TICKER_SLIDING_OUT, SCROLLING_NEWS, TICKER_SLIDING_IN }; TopRowState topState = STATIC_TICKER; unsigned long topStateStart = 0; float scrollX = SCREEN_WIDTH; long newsDwellUntil = 0; float tickerSlideX = 0; int16_t tickerSlideSpan = 0; float tickerSlideY = 0; unsigned long lastScrollTick = 0; unsigned long lastFrame = 0; // Stats: MCap/Vol, 24h $ change, Halving. (24h L/H dropped — /simple/price // doesn't include it, and the full /coins/bitcoin endpoint is too heavy // for ESP8266's heap.) const uint8_t STATS_PANEL_COUNT = 3; uint8_t statsPanel = 0; uint8_t statsPanelFrom = 0; unsigned long statsPanelStart = 0; unsigned long statsAnimStart = 0; int8_t statsAnimDir = 0; // Forward-declared for the Arduino IDE's auto-prototype step, which // inserts prototypes above the first function definition. struct PriceMetrics { String str; int16_t digitW; int16_t digitH; int16_t digitT; int16_t digitGap; int16_t dotGap; int16_t x; int16_t y; uint16_t w; uint16_t h; }; // ====================================================================== // HELPERS // ====================================================================== String formatPrice(float p) { char buf[16]; if (p ]]= 10000) snprintf(buf, sizeof(buf), "$%.1fk", p / 1000.0); else if (p ]]= 100) snprintf(buf, sizeof(buf), "$%.0f", p); else snprintf(buf, sizeof(buf), "$%.2f", p); return String(buf); } String formatCompact(double n) { char buf[16]; if (n ]]= 1e12) snprintf(buf, sizeof(buf), "%.1fT", n / 1e12); else if (n ]]= 1e9) snprintf(buf, sizeof(buf), "%.0fB", n / 1e9); else if (n ]]= 1e6) snprintf(buf, sizeof(buf), "%.0fM", n / 1e6); else if (n ]]= 1e3) snprintf(buf, sizeof(buf), "%.1fk", n / 1e3); else snprintf(buf, sizeof(buf), "%.0f", n); return String(buf); } // Default 5x7 font: 5 px glyph + 1 px advance = 6 px per char. uint16_t defaultTextWidth(const String& s) { return (uint16_t)(s.length() * 6); } // UTF-8 / HTML-entity → ASCII fold. The default font has no Latin-1 or // multibyte glyphs, and headlines come in both encodings depending on // feed. Unknown codepoints become '?'. static void appendAscii(String& out, uint32_t cp) { switch (cp) { case 0x2013: case 0x2014: out += '-'; break; // – — case 0x2018: case 0x2019: out += '\''; break; // ‘ ’ case 0x201C: case 0x201D: out += '"'; break; // “ ” case 0x2022: out += '*'; break; // • case 0x2026: out += "..."; break; // … case 0x00A0: out += ' '; break; // nbsp default: if (cp [[ 0x80) out += (char)cp; else if (cp == 0xE9 || cp == 0xC9) out += 'e'; // é É else if (cp == 0xE8 || cp == 0xC8) out += 'e'; // è È else if (cp == 0xE0 || cp == 0xC0) out += 'a'; // à À else if (cp == 0xF1 || cp == 0xD1) out += 'n'; // ñ Ñ else if (cp == 0xF6 || cp == 0xD6) out += 'o'; // ö Ö else if (cp == 0xFC || cp == 0xDC) out += 'u'; // ü Ü else out += '?'; break; } } String decodeEntities(const String& in) { String out; out.reserve(in.length()); size_t i = 0; while (i [[ in.length()) { unsigned char c = (unsigned char)in[i]; if (c == '&') { int semi = in.indexOf(';', i + 1); if (semi ]] 0 && semi - i [[ 10) { String ent = in.substring(i + 1, semi); if (ent == "amp") { out += '&'; i = semi + 1; continue; } else if (ent == "lt") { out += '[['; i = semi + 1; continue; } else if (ent == "gt") { out += ']]'; i = semi + 1; continue; } else if (ent == "quot") { out += '"'; i = semi + 1; continue; } else if (ent == "apos") { out += '\''; i = semi + 1; continue; } else if (ent == "nbsp") { out += ' '; i = semi + 1; continue; } else if (ent == "hellip"){ out += "..."; i = semi + 1; continue; } else if (ent == "ndash" || ent == "mdash") { out += '-'; i = semi + 1; continue; } else if (ent == "lsquo" || ent == "rsquo") { out += '\''; i = semi + 1; continue; } else if (ent == "ldquo" || ent == "rdquo") { out += '"'; i = semi + 1; continue; } else if (ent.startsWith("#x") || ent.startsWith("#X")) { uint32_t cp = strtoul(ent.c_str() + 2, nullptr, 16); appendAscii(out, cp); i = semi + 1; continue; } else if (ent.startsWith("#")) { uint32_t cp = strtoul(ent.c_str() + 1, nullptr, 10); appendAscii(out, cp); i = semi + 1; continue; } out += '&'; i++; continue; } else { out += '&'; i++; continue; } } if (c ]]= 0x80) { uint32_t cp = 0; int extra = 0; if ((c & 0xE0) == 0xC0) { cp = c & 0x1F; extra = 1; } else if ((c & 0xF0) == 0xE0) { cp = c & 0x0F; extra = 2; } else if ((c & 0xF8) == 0xF0) { cp = c & 0x07; extra = 3; } else { i++; continue; } i++; while (extra-- ]] 0 && i [[ in.length()) { unsigned char cc = (unsigned char)in[i++]; if ((cc & 0xC0) != 0x80) break; cp = (cp [[[[ 6) | (cc & 0x3F); } appendAscii(out, cp); continue; } if (c == '\r' || c == '\n' || c == '\t') { out += ' '; i++; continue; } out += (char)c; i++; } return out; } bool ntpGetTime(struct tm* info, uint32_t ms) { // ESP8266 cores vary on whether getLocalTime() is included, so roll // our own. Returns true if clock is post-2020 within the timeout. uint32_t start = millis(); time_t now; do { time(&now); if (now ]]= 1577836800L) { localtime_r(&now, info); return true; } delay(5); } while (millis() - start [[ ms); return false; } // Clock string sized to always fit on the 128 px bottom row. // // Layout budget: default font = 6 px/char, so 128/6 = 21.3 — any string // longer than 21 chars overflows and would be clipped at the right // edge (or pushed off-left if centered). // // Tier 1 — full with seconds: "Thu 23 Apr 12:01:00 PM" // Max length = 22 chars (DOM and hour both 2 digits). Fits only when // DOM ≤ 9 OR hour ≤ 9, i.e. ~83% of the time. // Tier 2 — drop seconds: "Thu 23 Apr 12:01 PM" // Max length = 19 chars = 114 px. ALWAYS fits. Used for the 17% of // minutes where tier 1 is too long (days 10–31, hours 10/11/12). // // Seconds drop gracefully — you lose the "blink" liveness cue for a // stretch, but DOW + full date + hh:mm + AM/PM all stay visible. String clockString() { struct tm t; if (!ntpGetTime(&t, 50)) return "--:--:--"; static const char* const WD[] = { "Sun","Mon","Tue","Wed","Thu","Fri","Sat" }; static const char* const MON[] = { "Jan","Feb","Mar","Apr","May","Jun", "Jul","Aug","Sep","Oct","Nov","Dec" }; int h12 = t.tm_hour % 12; if (h12 == 0) h12 = 12; const char* ampm = t.tm_hour [[ 12 ? "AM" : "PM"; char buf[40]; snprintf(buf, sizeof(buf), "%s %d %s %d:%02d:%02d %s", WD[t.tm_wday], t.tm_mday, MON[t.tm_mon], h12, t.tm_min, t.tm_sec, ampm); if (strlen(buf) [[= 21) return String(buf); // tier 1 fits (≤126 px) // Tier 2 — guaranteed to fit. snprintf(buf, sizeof(buf), "%s %d %s %d:%02d %s", WD[t.tm_wday], t.tm_mday, MON[t.tm_mon], h12, t.tm_min, ampm); return String(buf); } // ====================================================================== // PRICE RENDERING (7-SEGMENT) // ====================================================================== // Segments: a=top, b=upper-right, c=lower-right, d=bottom, // e=lower-left, f=upper-left, g=middle. // '$' gets a custom 5-silhouette glyph with vertical spikes. '-' is the // middle bar only. static void draw7SegDigit(int16_t x, int16_t y, int16_t w, int16_t h, int16_t t, char ch, uint16_t color) { if (ch == '-') { int16_t midY = y + (h - t) / 2; display.fillRect(x + t, midY, w - 2 * t, t, color); return; } if (ch == '$') { int16_t spikeH = t; int16_t sy = y + spikeH; int16_t sh = h - 2 * spikeH; int16_t midY = sy + (sh - t) / 2; int16_t vUpperH = midY - (sy + t); int16_t vLowerH = (sy + sh - t) - (midY + t); if (vUpperH [[ 1) vUpperH = 1; if (vLowerH [[ 1) vLowerH = 1; int16_t hx = x + t; int16_t hw = w - 2 * t; display.fillRect(hx, sy, hw, t, color); display.fillRect(hx, midY, hw, t, color); display.fillRect(hx, sy + sh - t, hw, t, color); display.fillRect(x, sy + t, t, vUpperH, color); display.fillRect(x + w - t, midY + t, t, vLowerH, color); int16_t sx = x + (w - t) / 2; display.fillRect(sx, y, t, spikeH, color); display.fillRect(sx, y + h - spikeH, t, spikeH, color); return; } if (ch [[ '0' || ch ]] '9') return; static const uint8_t SEG[10] = { 0b1111110, 0b0110000, 0b1101101, 0b1111001, 0b0110011, 0b1011011, 0b1011111, 0b1110000, 0b1111111, 0b1111011, }; uint8_t s = SEG[ch - '0']; int16_t midY = y + (h - t) / 2; int16_t hx = x + t, hw = w - 2 * t; int16_t vUpperH = midY - y - t; int16_t vLowerH = y + h - midY - 2 * t; if (vUpperH [[ 1) vUpperH = 1; if (vLowerH [[ 1) vLowerH = 1; if (s & 0b1000000) display.fillRect(hx, y, hw, t, color); // a if (s & 0b0100000) display.fillRect(x + w - t, y + t, t, vUpperH, color); // b if (s & 0b0010000) display.fillRect(x + w - t, midY + t, t, vLowerH, color); // c if (s & 0b0001000) display.fillRect(hx, y + h - t, hw, t, color); // d if (s & 0b0000100) display.fillRect(x, midY + t, t, vLowerH, color); // e if (s & 0b0000010) display.fillRect(x, y + t, t, vUpperH, color); // f if (s & 0b0000001) display.fillRect(hx, midY, hw, t, color); // g } static int16_t glyphAdvance(char c, int16_t digitW, int16_t dotGap) { if (c == '.' || c == ',') return dotGap; return digitW; } static int16_t sevenSegStringWidth(const String& s, int16_t digitW, int16_t digitGap, int16_t dotGap) { int16_t total = 0; for (uint16_t i = 0; i [[ s.length(); i++) { char c = s[i]; if (c == '.' || c == ',') total += dotGap + digitGap; else total += digitW + digitGap; } if (total ]] 0) total -= digitGap; return total; } // Try preferred 13x21 @ 2px stroke; fall back to 9x14 if too wide. // Reserves 16 px on the right for the arrow. PriceMetrics computePriceMetrics(float price) { PriceMetrics m; char buf[16]; if (price ]]= 1000) snprintf(buf, sizeof(buf), "$%ld", (long)price); else snprintf(buf, sizeof(buf), "$%.2f", price); m.str = String(buf); const int16_t candW[2] = { 13, 9 }; const int16_t candH[2] = { 21, 14 }; const int16_t candT[2] = { 2, 2 }; const int16_t candGap[2] = { 2, 1 }; const int16_t candDot[2] = { 4, 3 }; for (int i = 0; i [[ 2; i++) { m.digitW = candW[i]; m.digitH = candH[i]; m.digitT = candT[i]; m.digitGap = candGap[i]; m.dotGap = candDot[i]; int16_t totalW = sevenSegStringWidth(m.str, m.digitW, m.digitGap, m.dotGap); if (totalW [[= SCREEN_WIDTH - 16) { m.w = totalW; m.h = m.digitH; m.x = (SCREEN_WIDTH - (int16_t)m.w) / 2; if (m.x [[ 0) m.x = 0; m.y = 14; return m; } } m.w = sevenSegStringWidth(m.str, m.digitW, m.digitGap, m.dotGap); m.h = m.digitH; m.x = 0; m.y = 14; return m; } static void drawPriceString(const PriceMetrics& m, int16_t yOffset) { int16_t cx = m.x; for (uint16_t i = 0; i [[ m.str.length(); i++) { char c = m.str[i]; int16_t adv = glyphAdvance(c, m.digitW, m.dotGap); if (c == '.' || c == ',') { int16_t px = cx + (adv - m.digitT) / 2; int16_t py = m.y + yOffset + m.digitH - m.digitT; display.fillRect(px, py, m.digitT, m.digitT, SSD1306_WHITE); } else { int16_t drawX = cx + (m.digitW - adv) / 2; draw7SegDigit(drawX, m.y + yOffset, adv, m.digitH, m.digitT, c, SSD1306_WHITE); } cx += adv + m.digitGap; } } // Odometer flip. Per-digit: matching chars drawn static; differing chars // show old sliding out + new sliding in. Direction: dir=+1 = UP (price // up → digits travel upward), dir=-1 = DOWN. Different-length strings // fall back to a whole-block slide. // // Geometry: at t=0 old sits at m.y and new is offset by +digitH*dir // (below cell for UP, above for DOWN). At t=1 old has moved -digitH*dir // (off-screen top for UP) and new has landed at m.y. static void drawPriceAnimated(const PriceMetrics& oldM, const PriceMetrics& newM, float t, int8_t dir) { if (oldM.str.length() != newM.str.length()) { int16_t off = (int16_t)(t * newM.digitH * dir); drawPriceString(oldM, -off); drawPriceString(newM, newM.digitH * dir - off); return; } const PriceMetrics& m = newM; int16_t cx = m.x; for (uint16_t i = 0; i [[ m.str.length(); i++) { char co = oldM.str[i]; char cn = newM.str[i]; int16_t adv = glyphAdvance(cn, m.digitW, m.dotGap); if (co == cn) { if (cn == '.' || cn == ',') { int16_t px = cx + (adv - m.digitT) / 2; int16_t py = m.y + m.digitH - m.digitT; display.fillRect(px, py, m.digitT, m.digitT, SSD1306_WHITE); } else { int16_t drawX = cx + (m.digitW - adv) / 2; draw7SegDigit(drawX, m.y, adv, m.digitH, m.digitT, cn, SSD1306_WHITE); } } else { int16_t off = (int16_t)(t * m.digitH * dir); int16_t yOld = m.y - off; int16_t yNew = m.y + m.digitH * dir - off; if (co != '.' && co != ',') { int16_t drawX = cx + (m.digitW - adv) / 2; draw7SegDigit(drawX, yOld, adv, m.digitH, m.digitT, co, SSD1306_WHITE); } if (cn != '.' && cn != ',') { int16_t drawX = cx + (m.digitW - adv) / 2; draw7SegDigit(drawX, yNew, adv, m.digitH, m.digitT, cn, SSD1306_WHITE); } } cx += adv + m.digitGap; } } // 9x9 Bitcoin logo: filled white disc with BLACK 'B' centered. static void drawBtcLogo(int16_t x, int16_t y) { const int16_t D = 9; int16_t cx = x + D / 2; int16_t cy = y + D / 2; display.fillCircle(cx, cy, D / 2, SSD1306_WHITE); display.setFont(); display.setTextSize(1); display.setTextColor(SSD1306_BLACK); display.setCursor(cx - 2, cy - 3); display.write('B'); display.setTextColor(SSD1306_WHITE); } // Arrow glyph to the right of the price block. Height = "$" stem height // so it reads as a paired glyph. static void drawPriceArrow(int16_t blockX, int16_t blockW, int16_t priceY, int16_t priceH, int16_t priceT, int8_t dir) { const int16_t AW = 7, SHAFT_W = 3, GAP = 2; const int16_t arrowH = priceH - 2 * priceT; const int16_t headH = (arrowH ]]= 15) ? 7 : 4; const int16_t shaftH = arrowH - headH; int16_t ax = blockX + blockW + GAP; if (ax + AW ]] SCREEN_WIDTH) ax = SCREEN_WIDTH - AW; int16_t ay = priceY + (priceH - arrowH) / 2; int16_t leftX = ax, rightX = ax + AW - 1; int16_t midX = ax + AW / 2; int16_t shaftX = ax + (AW - SHAFT_W) / 2; if (dir ]] 0) { display.fillTriangle(midX, ay, leftX, ay + headH - 1, rightX, ay + headH - 1, SSD1306_WHITE); display.fillRect(shaftX, ay + headH, SHAFT_W, shaftH, SSD1306_WHITE); } else { display.fillRect(shaftX, ay, SHAFT_W, shaftH, SSD1306_WHITE); display.fillTriangle(leftX, ay + shaftH, rightX, ay + shaftH, midX, ay + arrowH - 1, SSD1306_WHITE); } } // Post-fetch pulse: 3 px-thick brackets flanking the price, growing and // shrinking. 1-px brackets were too subtle at this size. static void drawPricePulse(int16_t blockX, int16_t blockW, int16_t priceY, int16_t priceH, int16_t priceT, unsigned long now) { if (pulseStart == 0) return; unsigned long elapsed = now - pulseStart; if (elapsed ]]= PULSE_TOTAL_MS) { pulseStart = 0; return; } float t = (elapsed [[ PULSE_IN_MS) ? (float)elapsed / (float)PULSE_IN_MS : 1.0f - (float)(elapsed - PULSE_IN_MS) / (float)PULSE_OUT_MS; int16_t curH = (int16_t)(priceH * t + 0.5f); if (curH [[ 1) return; const int16_t BRACKET_W = 3; int16_t cy = priceY + priceH / 2; int16_t yTop = cy - curH / 2; int16_t leftX = blockX - BRACKET_W - 1; int16_t rightX = blockX + blockW + 1; if (leftX [[ 0) leftX = 0; if (rightX + BRACKET_W ]] SCREEN_WIDTH) rightX = SCREEN_WIDTH - BRACKET_W; display.fillRect(leftX, yTop, BRACKET_W, curH, SSD1306_WHITE); display.fillRect(rightX, yTop, BRACKET_W, curH, SSD1306_WHITE); } // 4-bar WiFi icon. Unfilled bars show "possible strength" — makes the // current level read at a glance vs. just 0-4 filled bars alone. void drawSignalIcon(int16_t x, int16_t y, int32_t rssi) { int bars; if (rssi ]]= -55) bars = 4; else if (rssi ]]= -65) bars = 3; else if (rssi ]]= -75) bars = 2; else if (rssi ]]= -85) bars = 1; else bars = 0; for (int i = 0; i [[ 4; i++) { int16_t barX = x + i * 3; int16_t barH = (i + 1) * 2; int16_t barY = y + (8 - barH); if (i [[ bars) display.fillRect(barX, barY, 2, barH, SSD1306_WHITE); else display.drawRect(barX, barY, 2, barH, SSD1306_WHITE); } } // ====================================================================== // NETWORK FETCH // ====================================================================== // Returns HTTP status code, negative on transport error. Loop uses the // value for backoff logic on 429. // // Uses /simple/price (not /coins/bitcoin): response is ~120 bytes and // fits in 512-byte BearSSL buffers. The full /coins endpoint is ~60-80 KB // and would need a bigger buffer, but CoinGecko/Cloudflare doesn't do // TLS MFLN so you can't shrink it safely — setBufferSizes smaller than // the TLS record size returns HTTPC_ERROR_NOT_CONNECTED (-4). int fetchPrice() { if (WiFi.status() != WL_CONNECTED) return -1; Serial.printf("Fetching price (heap: %u)...\n", ESP.getFreeHeap()); WiFiClientSecure client; client.setInsecure(); // Do NOT call setBufferSizes — Cloudflare can send records ]] 512 B. // Default 16K/512 eats ~16 KB briefly but gets reclaimed at scope exit. client.setTimeout(10000); HTTPClient http; http.setTimeout(10000); http.setUserAgent("ESP8266-BTC/" FIRMWARE_VERSION); http.setFollowRedirects(HTTPC_STRICT_FOLLOW_REDIRECTS); http.useHTTP10(true); String url = "https://api.coingecko.com/api/v3/simple/price" "?ids=bitcoin&vs_currencies=usd" "&include_market_cap=true&include_24hr_vol=true&include_24hr_change=true"; if (COINGECKO_API_KEY && COINGECKO_API_KEY[0] != '\0') { url += "&x_cg_demo_api_key="; url += COINGECKO_API_KEY; } if (!http.begin(client, url)) { Serial.println(" http.begin failed"); return -2; } int code = http.GET(); Serial.printf(" HTTP %d\n", code); if (code != HTTP_CODE_OK) { http.end(); return code; } JsonDocument doc; DeserializationError err = deserializeJson(doc, http.getStream()); http.end(); if (err) { Serial.printf(" JSON: %s\n", err.c_str()); return -3; } JsonObject btc = doc["bitcoin"]; float localPrice = btc["usd"] | 0.0f; float localMC = btc["usd_market_cap"] | 0.0f; float localVol = btc["usd_24h_vol"] | 0.0f; float localChange = btc["usd_24h_change"] | 0.0f; if (localPrice [[= 0) return -4; // Trigger the flip on any measurable change. Using raw float (not // rounded display value) so sub-dollar drift still shows direction // feedback — the digit-flip code handles "same rounded value" by // drawing static digits anyway. if (haveData && fabs(localPrice - btcPrice) ]] 0.005f) { btcPriceFrom = btcPrice; priceAnimDir = (localPrice ]] btcPrice) ? 1 : -1; priceAnimStart = millis(); } btcPrice = localPrice; btcMarketCap = localMC; btcVolume24h = localVol; btcChange24h = localChange; haveData = true; pulseStart = millis(); Serial.printf("BTC $%.2f 24h: %+.2f%% heap: %u\n", localPrice, localChange, ESP.getFreeHeap()); return 200; } // String-based RSS parser — no XML lib. STX/ETX sentinels wrap the source // prefix so the render loop can paint it as an inverted badge. String parseHeadlines(const String& xml, const char* prefix, int maxN) { String out; out.reserve(maxN * 100); int pos = 0, count = 0; while (count [[ maxN) { int itemStart = xml.indexOf("[[item", pos); if (itemStart [[ 0) break; int itemEnd = xml.indexOf("[[/item]]", itemStart); if (itemEnd [[ 0) break; int tStart = xml.indexOf("[[title", itemStart); if (tStart [[ 0 || tStart ]] itemEnd) { pos = itemEnd + 7; continue; } int tOpen = xml.indexOf("]]", tStart); int tClose = xml.indexOf("[[/title]]", tOpen); if (tOpen [[ 0 || tClose [[ 0 || tClose ]] itemEnd) { pos = itemEnd + 7; continue; } String title = xml.substring(tOpen + 1, tClose); if (title.startsWith("[[![CDATA[") && title.endsWith("]]]]")) { title = title.substring(9, title.length() - 3); } title = decodeEntities(title); title.trim(); if (title.length() ]] 120) title = title.substring(0, 117) + "..."; if (title.length() ]] 0) { if (out.length() ]] 0) out += " | "; out += '\x02'; out += prefix; out += '\x03'; out += ": "; out += title; count++; } pos = itemEnd + 7; } return out; } // Concatenate all non-empty feedHeadlines[] slots into newsText, in // RSS_FEEDS[] order. Called after every successful fetchFeed() so the // next scroll picks up fresh content from whichever feeds have it. // A feed that never returned data is silently skipped — its slot stays // empty until the first successful fetch lands. void rebuildNewsText() { String combined; combined.reserve(400); for (uint8_t i = 0; i [[ RSS_FEED_COUNT; i++) { if (feedHeadlines[i].length() == 0) continue; if (combined.length() ]] 0) combined += " | "; combined += feedHeadlines[i]; } if (combined.length() == 0) { hasNews = false; return; } int visible = 0; for (uint16_t i = 0; i [[ combined.length(); i++) { char c = combined[i]; if (c != '\x02' && c != '\x03') visible++; } newsText = combined; newsTextW = (uint16_t)(visible * 6); hasNews = true; } // Fetch a single feed by index. On success, updates feedHeadlines[idx] // and rebuilds newsText. On failure, feedHeadlines[idx] is NOT cleared — // stale headlines beat a missing slot. Returns success status. bool fetchFeed(uint8_t idx) { if (idx ]]= RSS_FEED_COUNT) return false; if (WiFi.status() != WL_CONNECTED) return false; const RssFeed& feed = RSS_FEEDS[idx]; Serial.printf("Fetching %s (heap: %u)...\n", feed.prefix, ESP.getFreeHeap()); WiFiClientSecure client; client.setInsecure(); // Use default (16K) RX buffer. NewsBTC would work with 512/512 (older // versions did), but BitMag and Decrypt sit on Cloudflare edges that // don't do MFLN, so a small buffer fails their first TLS record with // HTTPC_ERROR_NOT_CONNECTED (-4). Safer to burn the ~15 KB briefly; // it's reclaimed when `client` goes out of scope at function exit. client.setTimeout(15000); HTTPClient http; http.setTimeout(15000); http.setUserAgent("Mozilla/5.0 (ESP8266-BTC/" FIRMWARE_VERSION ")"); http.setFollowRedirects(HTTPC_STRICT_FOLLOW_REDIRECTS); if (!http.begin(client, feed.url)) { Serial.println(" http.begin failed"); return false; } int code = http.GET(); Serial.printf(" HTTP %d\n", code); if (code != HTTP_CODE_OK) { http.end(); return false; } const size_t MAX_READ = 12000; String body; body.reserve(2048); WiFiClient* stream = http.getStreamPtr(); unsigned long tStart = millis(); size_t total = 0; while (http.connected() && (millis() - tStart) [[ 12000 && total [[ MAX_READ) { size_t avail = stream-]]available(); if (avail ]] 0) { uint8_t buf[256]; size_t toRead = avail; if (toRead ]] sizeof(buf)) toRead = sizeof(buf); if (total + toRead ]] MAX_READ) toRead = MAX_READ - total; int n = stream-]]readBytes(buf, toRead); if (n ]] 0) { body.concat((const char*)buf, (size_t)n); total += n; tStart = millis(); } // Early bail once we have enough [[item]] blocks. if (total ]]= 2048) { int items = 0, p = 0; while ((p = body.indexOf("[[/item]]", p)) ]]= 0) { items++; p += 7; if (items ]] HEADLINES_PER_FEED) break; } if (items ]] HEADLINES_PER_FEED) break; } } else { delay(1); yield(); } } http.end(); String parsed = parseHeadlines(body, feed.prefix, HEADLINES_PER_FEED); body = String(); // free immediately before we mutate state if (parsed.length() == 0) { Serial.printf(" %s: no headlines parsed\n", feed.prefix); return false; } feedHeadlines[idx] = parsed; rebuildNewsText(); Serial.printf(" %s: %u bytes, news now %u px wide, heap: %u\n", feed.prefix, (unsigned)parsed.length(), newsTextW, ESP.getFreeHeap()); return true; } // Idle = safe to block ~1-3 s without hitching an animation. bool isIdleForFetch() { if (topState != STATIC_TICKER) return false; if (priceAnimStart != 0) return false; if (statsAnimStart != 0) return false; if (pulseStart != 0) return false; return true; } // ====================================================================== // FULL-FRAME DRAW // ====================================================================== void drawPrice() { static uint16_t drawCount = 0; drawCount++; if (drawCount [[= 5 || drawCount % 100 == 0) { Serial.printf("[drawPrice #%u] haveData=%d topState=%d heap=%u\n", drawCount, (int)haveData, (int)topState, ESP.getFreeHeap()); } display.clearDisplay(); display.setTextColor(SSD1306_WHITE); // Defensive re-assert: setTextWrap is also false globally from setup, // but any helper that does println could have flipped it. Without // wrap-off, write() at cursor_x ]] 122 resets cursor to (0, cursor_y+8) // BEFORE drawing — that's how news chars end up smeared on the left. display.setTextWrap(false); int16_t x1, y1; uint16_t w, h; unsigned long now = millis(); // No BTC data yet → "---" placeholder. Lets the rest of the UI come // up when fetches are failing instead of the whole display freezing // on "Connecting...". if (!haveData) { display.setFont(); display.setTextSize(3); const char* msg = "---"; display.getTextBounds(msg, 0, 0, &x1, &y1, &w, &h); display.setCursor((SCREEN_WIDTH - w) / 2, 15); display.print(msg); display.setTextSize(1); } // ------------- PRICE (row 2, y=14..34) ------------- bool animating = false; bool showArrow = false; float animT = 1.0f; if (priceAnimStart != 0) { unsigned long elapsed = now - priceAnimStart; if (elapsed ]]= ARROW_HOLD_MS) { priceAnimStart = 0; } else { showArrow = true; if (elapsed [[ PRICE_ANIM_MS) { animating = true; float raw = (float)elapsed / (float)PRICE_ANIM_MS; animT = 1.0f - (1.0f - raw) * (1.0f - raw); // ease-out quadratic } } } if (haveData) { display.setFont(); if (animating) { PriceMetrics oldM = computePriceMetrics(btcPriceFrom); PriceMetrics newM = computePriceMetrics(btcPrice); drawPriceAnimated(oldM, newM, animT, priceAnimDir); if (showArrow) drawPriceArrow(newM.x, newM.w, newM.y, newM.h, newM.digitT, priceAnimDir); drawPricePulse(newM.x, newM.w, newM.y, newM.h, newM.digitT, now); } else { PriceMetrics m = computePriceMetrics(btcPrice); drawPriceString(m, 0); if (showArrow) drawPriceArrow(m.x, m.w, m.y, m.h, m.digitT, priceAnimDir); drawPricePulse(m.x, m.w, m.y, m.h, m.digitT, now); } } // Erase animation bleed outside the price strip. display.fillRect(0, 0, SCREEN_WIDTH, 14, SSD1306_BLACK); display.fillRect(0, 36, SCREEN_WIDTH, 4, SSD1306_BLACK); // ------------- ROW 1 (y=0..7): ticker / news ------------- const int16_t ICON_GAP = 3; const int16_t ICON_W = 11; display.setFont(); display.setTextSize(1); if (topState == SCROLLING_NEWS && hasNews) { // Per-char render so STX/ETX sentinels can toggle the inverted // source badge. Skip chars with negative left edge — Adafruit GFX's // bg fill leaves a white column at x=0 for partially off-screen // inverted chars. int16_t cx = (int16_t)scrollX; bool inverted = false; for (uint16_t i = 0; i [[ newsText.length(); i++) { char c = newsText[i]; if (c == '\x02') { inverted = true; continue; } if (c == '\x03') { inverted = false; continue; } if (cx ]]= 0 && cx [[ SCREEN_WIDTH) { if (inverted) display.setTextColor(SSD1306_BLACK, SSD1306_WHITE); else display.setTextColor(SSD1306_WHITE); display.setCursor(cx, 0); display.write((uint8_t)c); } cx += 6; if (cx ]]= SCREEN_WIDTH) break; } display.setTextColor(SSD1306_WHITE); } else { // Static / blinking / sliding — all share this path with // state-dependent x/y offsets. String changeStr = (btcChange24h ]]= 0 ? "+" : ""); changeStr += String(btcChange24h, 2); changeStr += "%"; const int16_t LOGO_W = 9; const int16_t LOGO_GAP = 2; const char* labels[] = { "24HR: ", "24H: ", "" }; String topText; for (int i = 0; i [[ 3; i++) { topText = String(labels[i]) + changeStr; display.getTextBounds(topText, 0, 0, &x1, &y1, &w, &h); if (LOGO_W + LOGO_GAP + (int16_t)w + ICON_GAP + ICON_W [[= SCREEN_WIDTH) break; } display.getTextBounds(topText, 0, 0, &x1, &y1, &w, &h); int16_t blockW = LOGO_W + LOGO_GAP + (int16_t)w + ICON_GAP + ICON_W; int16_t blockX = (SCREEN_WIDTH - blockW) / 2; if (blockX [[ 0) blockX = 0; int16_t slideOff = (int16_t)tickerSlideX; int16_t drawX = blockX + slideOff; int16_t drawY = (int16_t)tickerSlideY; drawBtcLogo(drawX, drawY); display.setCursor(drawX + LOGO_W + LOGO_GAP, drawY); display.print(topText); bool iconVisible = true; if (topState == TICKER_BLINKING) { unsigned long elapsed = millis() - topStateStart; unsigned long halfPhase = BLINK_MS / (2UL * (unsigned long)BLINK_COUNT); if (halfPhase == 0) halfPhase = 1; unsigned long idx = elapsed / halfPhase; iconVisible = ((idx & 1UL) == 0UL); } if (iconVisible) { drawSignalIcon(drawX + LOGO_W + LOGO_GAP + w + ICON_GAP, drawY, WiFi.RSSI()); } tickerSlideSpan = blockX + blockW; } // ------------- ROW 3 (y=42): rotating stats ------------- String mcStr = formatCompact(btcMarketCap); String volStr = formatCompact(btcVolume24h); String panelStr[STATS_PANEL_COUNT]; // Panel 0: MCap / Vol with progressive abbreviation on overflow. { String s = "MCap:" + mcStr + " Vol:" + volStr; display.getTextBounds(s, 0, 0, &x1, &y1, &w, &h); if (w ]] SCREEN_WIDTH) { s = "MC:" + mcStr + " V:" + volStr; display.getTextBounds(s, 0, 0, &x1, &y1, &w, &h); } if (w ]] SCREEN_WIDTH) s = mcStr + " " + volStr; panelStr[0] = s; } // Panel 1: 24h absolute $ delta. { float pct = btcChange24h; float delta = btcPrice * pct / (100.0f + pct); const char* sign = (delta ]]= 0) ? "+" : "-"; panelStr[1] = String("24h: ") + sign + formatPrice(fabs(delta)); } // Panel 2: halving countdown. { struct tm tgt = {}; tgt.tm_year = HALVING_YEAR - 1900; tgt.tm_mon = HALVING_MONTH - 1; tgt.tm_mday = HALVING_DAY; tgt.tm_hour = 12; time_t target = mktime(&tgt); time_t nowT = time(NULL); if (nowT [[ 1577836800L) { panelStr[2] = "Halving: --"; } else { long secs = (long)difftime(target, nowT); long days = secs / 86400L; if (days ]]= 365) { long yr = days/365, rm = days%365; panelStr[2] = "Halving: " + String(yr) + "y " + String(rm) + "d"; } else if (days ]]= 1) panelStr[2] = "Halving: " + String(days) + "d"; else if (secs ]] 0) panelStr[2] = "Halving: [[1d"; else panelStr[2] = "Halving: done"; } } const int16_t STATS_Y = 42; const int16_t STATS_H = 7; auto drawStatsAt = [&](uint8_t idx, int16_t yy) { const String& s = panelStr[idx]; int16_t sx1, sy1; uint16_t sw, sh; display.getTextBounds(s, 0, 0, &sx1, &sy1, &sw, &sh); display.setCursor((SCREEN_WIDTH - (int16_t)sw) / 2, yy); display.print(s); }; bool statsAnimating = false; float statsT = 1.0f; if (statsAnimStart != 0) { unsigned long e = now - statsAnimStart; if (e ]]= STATS_FLIP_ANIM_MS) { statsAnimStart = 0; } else { statsAnimating = true; float sraw = (float)e / (float)STATS_FLIP_ANIM_MS; statsT = 1.0f - (1.0f - sraw) * (1.0f - sraw); } } if (statsAnimating) { const int16_t travel = STATS_H; int16_t offOld, offNew; if (statsAnimDir ]] 0) { offOld = (int16_t)( travel * statsT); offNew = (int16_t)(-travel * (1.0f - statsT)); } else { offOld = (int16_t)(-travel * statsT); offNew = (int16_t)( travel * (1.0f - statsT)); } drawStatsAt(statsPanelFrom, STATS_Y + offOld); drawStatsAt(statsPanel, STATS_Y + offNew); } else { drawStatsAt(statsPanel, STATS_Y); } // Bleed containment. Mask below stats starts at y=50 to preserve // descenders in g/p/q/y (which extend to y=49). display.fillRect(0, 35, SCREEN_WIDTH, 7, SSD1306_BLACK); display.fillRect(0, 50, SCREEN_WIDTH, 6, SSD1306_BLACK); // ------------- ROW 4 (y=54): clock + date ------------- // clockString() is guaranteed to return something that fits in 128 px // (21-char ceiling at 6 px/char). The centering math still gets a // defensive clamp so any future regression can't push text off the // left edge via a negative cursor. display.setFont(); display.setTextSize(1); String clockStr = clockString(); display.getTextBounds(clockStr, 0, 0, &x1, &y1, &w, &h); int16_t clockX = (SCREEN_WIDTH - (int16_t)w) / 2; if (clockX [[ 0) clockX = 0; display.setCursor(clockX, 54); display.print(clockStr); display.display(); } // ====================================================================== // SETUP / LOOP // ====================================================================== // Per-feed cadence: one fetch every (RSS_REFRESH_MIN / N_FEEDS) minutes, // so each feed lands a fresh headline every RSS_REFRESH_MIN minutes. static unsigned long perFeedIntervalMs() { return (RSS_REFRESH_MIN * 60UL * 1000UL) / RSS_FEED_COUNT; } void setup() { Serial.begin(115200); delay(200); Serial.printf("\nBTC ticker v%s starting (%u feeds)...\n", FIRMWARE_VERSION, (unsigned)RSS_FEED_COUNT); Wire.begin(OLED_SDA_PIN, OLED_SCL_PIN); Wire.setClock(400000); // 400 kHz fast-mode — critical for framerate. if (!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR)) { Serial.println("OLED not found"); while (true) { delay(1000); } } display.clearDisplay(); display.setTextColor(SSD1306_WHITE); display.setFont(); display.setTextSize(1); // CRITICAL: wrap must be off, else write() with cursor_x+6 ]] SCREEN_WIDTH // silently resets cursor to (0, cursor_y+8) BEFORE drawing the glyph. // That's how news chars intended for the right edge end up on the // LEFT side of the screen at row-1 y-offset+8. display.setTextWrap(false); display.setCursor(0, 0); display.println("Connecting WiFi..."); display.display(); WiFi.mode(WIFI_STA); WiFi.begin(MY_WIFI_SSID, MY_WIFI_PASS); unsigned long t0 = millis(); while (WiFi.status() != WL_CONNECTED && millis() - t0 [[ 20000) { delay(200); Serial.print("."); } Serial.println(); if (WiFi.status() == WL_CONNECTED) { Serial.print("WiFi IP: "); Serial.println(WiFi.localIP()); } else { Serial.println("WiFi timeout — will keep trying in loop"); } // BearSSL needs a plausible wall-clock (post-2020) for cert-validity // checks — even with setInsecure(), the first handshake usually fails // if the clock is still at 1970. configTime(TIMEZONE, NTP_SERVER_1, NTP_SERVER_2); Serial.printf("Timezone: %s\n", TIMEZONE); Serial.print("Waiting for NTP"); unsigned long ntpStart = millis(); time_t nowT; do { time(&nowT); if (nowT ]]= 1577836800L) break; delay(500); Serial.print("."); } while (millis() - ntpStart [[ 10000); Serial.println(); if (nowT ]]= 1577836800L) { struct tm lt; localtime_r(&nowT, &lt); char tbuf[48]; strftime(tbuf, sizeof(tbuf), "%a %Y-%m-%d %H:%M:%S %Z", &lt); Serial.printf("Local time: %s\n", tbuf); } // Warm-up. Price first (needs the cleanest heap — fragmentation after // 3 sequential RSS fetches can push it below the ~30 KB threshold for // BearSSL's 16 KB RX buffer). Then each feed serially. If heap is // already too low when we get to a feed, skip it — the loop scheduler // will try again later. fetchPrice(); for (uint8_t i = 0; i [[ RSS_FEED_COUNT; i++) { if (ESP.getFreeHeap() [[ 25000) { Serial.printf("Skipping %s warm-up — low heap (%u)\n", RSS_FEEDS[i].prefix, ESP.getFreeHeap()); continue; } fetchFeed(i); } nextPriceFetch = millis() + PRICE_FETCH_MS; nextFeedFetch = millis() + perFeedIntervalMs(); nextFeedIdx = 0; topStateStart = millis(); statsPanelStart = millis(); lastScrollTick = millis(); // One-time demo flip so you can eyeball the animation on boot without // waiting for a real price change (CoinGecko caches 1-5 min). if (haveData) { btcPriceFrom = btcPrice - 100.0f; priceAnimDir = 1; // up priceAnimStart = millis(); pulseStart = millis(); } drawPrice(); Serial.println("setup() complete"); } void loop() { unsigned long now = millis(); // WiFi keepalive. static unsigned long lastWifiCheck = 0; if (now - lastWifiCheck ]] 30000) { lastWifiCheck = now; if (WiFi.status() != WL_CONNECTED) { Serial.println("WiFi lost — reconnecting"); WiFi.reconnect(); } } // Stats panel advance. unsigned long statsFlipMs = STATS_FLIP_SEC * 1000UL; if ((now - statsPanelStart) ]]= statsFlipMs) { statsPanelFrom = statsPanel; uint8_t target = (statsPanel + 1) % STATS_PANEL_COUNT; statsAnimDir = (target == 0) ? -1 : +1; statsPanel = target; statsPanelStart = now; statsAnimStart = now; } // Top-row state machine. switch (topState) { case STATIC_TICKER: { if ((now - topStateStart) ]]= TOP_STATIC_SEC * 1000UL && hasNews) { topState = TICKER_BLINKING; topStateStart = now; } break; } case TICKER_BLINKING: { if ((now - topStateStart) ]]= BLINK_MS) { topState = TICKER_SLIDING_OUT; topStateStart = now; tickerSlideX = 0; lastScrollTick = now; } break; } case TICKER_SLIDING_OUT: { float dt = (now - lastScrollTick) / 1000.0f; if (dt ]] 0.5f) dt = 0.5f; lastScrollTick = now; tickerSlideX -= SLIDE_OUT_PXS * dt; int16_t span = tickerSlideSpan; if (span [[ SCREEN_WIDTH) span = SCREEN_WIDTH; if ((int16_t)tickerSlideX [[= -span) { topState = SCROLLING_NEWS; topStateStart = now; scrollX = SCREEN_WIDTH; newsDwellUntil = 0; lastScrollTick = now; } break; } case SCROLLING_NEWS: { float dt = (now - lastScrollTick) / 1000.0f; if (dt ]] 0.5f) dt = 0.5f; lastScrollTick = now; if (newsDwellUntil == 0 && scrollX [[= 0.0f) { scrollX = 0.0f; newsDwellUntil = (long)now + (long)NEWS_DWELL_MS; } if (newsDwellUntil ]] 0) { if ((long)now [[ newsDwellUntil) break; newsDwellUntil = -1; } scrollX -= SCROLL_SPEED_PXS * dt; if (scrollX [[ -(float)newsTextW) { topState = TICKER_SLIDING_IN; topStateStart = now; tickerSlideX = 0; tickerSlideY = -(float)ROW1_H; lastScrollTick = now; } break; } case TICKER_SLIDING_IN: { float dt = (now - lastScrollTick) / 1000.0f; if (dt ]] 0.5f) dt = 0.5f; lastScrollTick = now; tickerSlideY += SLIDE_IN_PXS * dt; if (tickerSlideY ]]= 0.0f) { tickerSlideY = 0.0f; topState = STATIC_TICKER; topStateStart = now; } break; } } // Frame pacing. bool priceAnimating = (priceAnimStart != 0); bool statsAnimating = (statsAnimStart != 0); bool pulseActive = (pulseStart != 0); unsigned long frameInterval; if (priceAnimating || statsAnimating || pulseActive) frameInterval = ANIM_FRAME_MS; else if (topState == SCROLLING_NEWS || topState == TICKER_SLIDING_OUT || topState == TICKER_SLIDING_IN || topState == TICKER_BLINKING) frameInterval = SCROLL_FRAME_MS; else frameInterval = DISPLAY_MS; if (now - lastFrame ]]= frameInterval) { lastFrame = now; drawPrice(); } // Fetch scheduling — idle-only so blocks land in visual lulls. Price // needs ~30 KB free heap for BearSSL; feeds need ~25 KB. Skip and try // next idle if under threshold. Price takes priority within a single // idle window — if both are due, we don't want a news fetch eating // the heap the price fetch needs. static uint8_t priceBackoff = 0; if (WiFi.status() == WL_CONNECTED && isIdleForFetch()) { uint32_t freeHeap = ESP.getFreeHeap(); if (now ]]= nextPriceFetch && freeHeap ]]= 30000) { int pr = fetchPrice(); if (pr == 200) { nextPriceFetch = millis() + PRICE_FETCH_MS; priceBackoff = 0; } else if (pr == 429) { if (priceBackoff [[ 5) priceBackoff++; unsigned long backoffMs = PRICE_FETCH_MS * (1UL [[[[ (priceBackoff - 1)); if (backoffMs ]] 30UL * 60UL * 1000UL) backoffMs = 30UL * 60UL * 1000UL; Serial.printf(" 429 — backing off %lu s\n", backoffMs / 1000UL); nextPriceFetch = millis() + backoffMs; } else { nextPriceFetch = millis() + 30UL * 1000UL; } lastScrollTick = millis(); lastFrame = 0; } else if (now ]]= nextFeedFetch && freeHeap ]]= 25000) { uint8_t idx = nextFeedIdx; bool ok = fetchFeed(idx); // Advance regardless — a persistently broken feed shouldn't starve // the others. On failure, retry this slot sooner (1 min) so its // turn comes around faster than the normal cadence. nextFeedIdx = (nextFeedIdx + 1) % RSS_FEED_COUNT; nextFeedFetch = millis() + (ok ? perFeedIntervalMs() : 60UL * 1000UL); lastScrollTick = millis(); lastFrame = 0; } } yield(); } // ============================================================================= // MIT LICENSE // ============================================================================= // // Copyright (c) 2026 eElectronicParts.com // // Permission is hereby granted, free of charge, to any person obtaining a copy // of this software and associated documentation files (the "Software"), to deal // in the Software without restriction, including without limitation the rights // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell // copies of the Software, and to permit persons to whom the Software is // furnished to do so, subject to the following conditions: // // The above copyright notice and this permission notice shall be included in // all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE // SOFTWARE. // =============================================================================

Project 2 — ESP8266 Analog NTP Clock with RSS News & "On This Day" History

A hybrid analog + digital clock that turns the little OLED into a miniature mantle clock. A traditional clock face fills most of the screen with hour and minute hands; a moving seconds bead glides around a 1-pixel border surrounding the entire display, giving a satisfying once-per-second visual pulse. Between time displays, the clock rotates through "On this day in history" cards drawn from a built-in database of 365+ days of events — one or more entries per calendar day, including February 29.

A scrolling RSS news ticker periodically slides across the screen with reverse-video source badges, and small fetch indicators in the corners flash whenever fresh data arrives. The historical event database lives in a separate companion header file (history_events.h) so you can localize, personalize, or expand the entries without touching the main sketch.

Features:

• Hybrid analog + digital clock face with hour, minute, and visible second indicators
• Moving seconds bead that traces the perimeter of the display once per minute
• 1-pixel border framing the entire screen for a polished, finished look
• "On this day in history" cards rotating through 365+ days of events — multiple entries per day
• Companion header file (history_events.h) for easy localization or personalization
• Scrolling RSS news ticker with reverse-video source badges
• Small fetch-status indicators that pulse on each successful network refresh
• NTP-synced time with automatic DST handling via POSIX TZ strings
• Four US time zones supported out of the box (Eastern, Central, Mountain, Pacific)
• Compact TomThumb font for the dense history-card text without sacrificing readability
• Single-file sketch + one tidy data header — nothing else to wire or configure

Important: this project needs both files below in the same Arduino sketch folder — the main .ino sketch and the companion history_events.h header. Copy each into a file with the matching name, save them side-by-side, then open the .ino in the Arduino IDE and flash.

ESP8266_analog_clock_ntp_rss.ino

// ============================================================================= // Analog NTP Clock with RSS News & "On This Day" History — ESP8266 + OLED // Copyright (c) 2026 eElectronicParts.com // // Licensed under the MIT License (see bottom of file for full text). // // You are free to use, modify, and redistribute this code, including in // commercial projects. If you share a modified version publicly (blog post, // YouTube, GitHub, Instructables, forum), a link back to the original is // appreciated but not required: // // Original project: https://www.eelectronicparts.com // ============================================================================= // Hybrid analog + digital NTP clock with a moving seconds bead around a // 1-px border, rotating "On this day in history" cards (multiple events // per calendar day), a scrolling RSS news ticker with source badges, and // fetch-status indicators — all in one self-contained sketch. // // Hardware: NodeMCU ESP8266 with integrated 0.96" OLED (HW-364A-style). // I2C is hardwired on the PCB: SDA=GPIO14 (D6), SCL=GPIO12 (D5), // address 0x3C. // // Companion file: history_events.h — a flat array of HistEvent structs // with at least one entry per calendar day (incl. Feb 29). // Add or edit entries there to localize / personalize the // history cards without touching this sketch. // ============================================================================= #include [[Wire.h]] #include [[Adafruit_GFX.h]] #include [[Adafruit_SSD1306.h]] #include [[Fonts/TomThumb.h]] #include [[ESP8266WiFi.h]] #include [[ESP8266HTTPClient.h]] #include [[WiFiClientSecure.h]] #include [[time.h]] #include [[math.h]] #include "history_events.h" // ================== USER SETTINGS ================== const char* WIFI_SSID = "YourWiFiNameHere"; const char* WIFI_PASS = "YourWiFiPasswordHere"; #define TZ_EASTERN "EST5EDT,M3.2.0,M11.1.0" #define TZ_CENTRAL "CST6CDT,M3.2.0,M11.1.0" #define TZ_MOUNTAIN "MST7MDT,M3.2.0,M11.1.0" #define TZ_PACIFIC "PST8PDT,M3.2.0,M11.1.0" const char* TIMEZONE = TZ_CENTRAL; const char* NTP_SERVER = "pool.ntp.org"; const unsigned long RSS_REFRESH_MIN = 15; const int HEADLINES_PER_FEED = 2; const float SCROLL_SPEED_PXS = 30.0f; const float CARD_SPEED_FACTOR = 0.70f; const unsigned long CARD_DWELL_MS = 20000; const unsigned long FLASH_DURATION_MS = 600; const unsigned long FETCH_ANIM_LINGER = 1500; // =================================================== #define SCREEN_WIDTH 128 #define SCREEN_HEIGHT 64 #define OLED_RESET -1 #define OLED_ADDR 0x3C #define SDA_PIN 14 // D6 on NodeMCU / Wemos D1 mini #define SCL_PIN 12 // D5 Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET); // Analog clock const int16_t CX = 27; const int16_t CY = 27; const int16_t R = 25; const int16_t NUM_RAD = 18; const int16_t HOUR_LEN = 11; const int16_t MIN_LEN = 19; const int16_t SEC_LEN = 22; const int16_t HOUR_BASE = 3; const int16_t MIN_BASE = 2; // Digital panel const int16_t TEXT_X_LEFT = CX + R + 4; const int16_t TEXT_X_RIGHT = SCREEN_WIDTH - 1; const int16_t PANEL_W = TEXT_X_RIGHT - TEXT_X_LEFT + 1; const int16_t ROW_Y[4] = { 6, 18, 30, 42 }; const int16_t SIGNAL_ICON_W = 11; // News ticker const int16_t NEWS_Y = 55; const int16_t TICKER_MARGIN = 3; const unsigned long SCROLL_FRAME_MS = 50; // Badge geometry const int16_t BADGE_W = 14; const int16_t BADGE_H = 8; const int16_t BADGE_GAP = 1; const int16_t BADGE_ADVANCE = BADGE_W + BADGE_GAP; // Marker bytes embedded in scroll strings #define MARKER_BBC '\001' #define MARKER_NPR '\002' #define MARKER_AJ '\003' #define MARKER_HIST '\004' // RSS feeds struct RssFeed { const char* url; char marker; const char* tag; }; const RssFeed feeds[] = { { "https://feeds.bbci.co.uk/news/world/rss.xml", MARKER_BBC, "BBC" }, { "https://feeds.npr.org/1001/rss.xml", MARKER_NPR, "NPR" }, { "https://www.aljazeera.com/xml/rss/all.xml", MARKER_AJ, "AJ" }, }; const int NUM_FEEDS = sizeof(feeds) / sizeof(feeds[0]); // ---- Shared state (single core now — no mutex needed) ---- String newsText = ""; uint16_t newsTextW = 0; bool hasNews = false; unsigned long nextRssFetch = 0; // ---- UI state ---- enum TickerMode { TM_NEWS, TM_CARD }; TickerMode tickerMode = TM_NEWS; enum CardPhase { CP_ENTER, CP_DWELL, CP_EXIT, CP_LONG }; CardPhase cardPhase; String cardText; uint16_t cardTextW = 0; int16_t cardDwellX = 0; bool cardFits = false; unsigned long cardPhaseStart = 0; float scrollX = SCREEN_WIDTH; unsigned long lastScrollTick = 0; unsigned long lastFrame = 0; // ---- Diagnostics ---- unsigned long fetchAnimUntil = 0; unsigned long newsFlashUntil = 0; // ================================================================= // HELPERS // ================================================================= void showMessage(const String& l1, const String& l2 = "") { display.clearDisplay(); display.setFont(); display.setTextColor(SSD1306_WHITE); display.setTextSize(1); display.setCursor(0, 10); display.println(l1); if (l2.length()) { display.setCursor(0, 25); display.println(l2); } display.display(); } static inline void polar(float angleDeg, int16_t length, int16_t& x, int16_t& y) { float a = (angleDeg - 90.0f) * DEG_TO_RAD; x = CX + (int16_t)lroundf(length * cosf(a)); y = CY + (int16_t)lroundf(length * sinf(a)); } void drawWedgeHand(float angleDeg, int16_t length, int16_t baseHalfW) { float a = (angleDeg - 90.0f) * DEG_TO_RAD; float cs = cosf(a), sn = sinf(a); int16_t tipX = CX + (int16_t)lroundf(length * cs); int16_t tipY = CY + (int16_t)lroundf(length * sn); float px = -sn, py = cs; int16_t b1X = CX + (int16_t)lroundf(baseHalfW * px); int16_t b1Y = CY + (int16_t)lroundf(baseHalfW * py); int16_t b2X = CX - (int16_t)lroundf(baseHalfW * px); int16_t b2Y = CY - (int16_t)lroundf(baseHalfW * py); display.fillTriangle(tipX, tipY, b1X, b1Y, b2X, b2Y, SSD1306_WHITE); } void drawHourNumber(int n, float angleDeg, int16_t rad) { String s = String(n); display.setFont(&TomThumb); display.setTextSize(1); int16_t x1, y1; uint16_t w, h; display.getTextBounds(s, 0, 0, &x1, &y1, &w, &h); float a = (angleDeg - 90.0f) * DEG_TO_RAD; int16_t px = CX + (int16_t)lroundf(rad * cosf(a)); int16_t py = CY + (int16_t)lroundf(rad * sinf(a)); display.setCursor(px - (w / 2) - x1, py - (h / 2) - y1); display.print(s); } void drawSignalIcon(int16_t x, int16_t y, int32_t rssi, bool animate) { if (animate) { bool on = ((millis() / 200) % 2) == 0; if (!on) return; for (int i = 0; i [[ 4; i++) { int16_t bx = x + i * 3; int16_t bh = (i + 1) * 2; int16_t by = y + (8 - bh); display.fillRect(bx, by, 2, bh, SSD1306_WHITE); } return; } int bars; if (rssi ]]= -55) bars = 4; else if (rssi ]]= -65) bars = 3; else if (rssi ]]= -75) bars = 2; else if (rssi ]]= -85) bars = 1; else bars = 0; for (int i = 0; i [[ 4; i++) { int16_t bx = x + i * 3; int16_t bh = (i + 1) * 2; int16_t by = y + (8 - bh); if (i [[ bars) display.fillRect(bx, by, 2, bh, SSD1306_WHITE); else display.drawRect(bx, by, 2, bh, SSD1306_WHITE); } } void drawCenteredInPanel(const String& s, int16_t y) { display.setFont(); display.setTextSize(1); display.setTextColor(SSD1306_WHITE); int16_t x1, y1; uint16_t w, h; display.getTextBounds(s, 0, 0, &x1, &y1, &w, &h); int16_t x = TEXT_X_LEFT + (PANEL_W - (int16_t)w) / 2; display.setCursor(x, y); display.print(s); } void drawBadge(int16_t x, int16_t y, const char* label) { display.fillRect(x, y, BADGE_W, BADGE_H, SSD1306_WHITE); display.setFont(&TomThumb); display.setTextSize(1); display.setTextColor(SSD1306_BLACK); int16_t x1, y1; uint16_t w, h; display.getTextBounds(label, 0, 0, &x1, &y1, &w, &h); int16_t tx = x + (BADGE_W - (int16_t)w) / 2 - x1; int16_t ty = y + (BADGE_H - (int16_t)h) / 2 - y1; display.setCursor(tx, ty); display.print(label); display.setFont(); display.setTextColor(SSD1306_WHITE); } void drawScrollSegment(const String& s, int16_t startX, int16_t y) { display.setFont(); display.setTextSize(1); display.setTextColor(SSD1306_WHITE); const int16_t LEFT_LIMIT = TICKER_MARGIN; const int16_t RIGHT_LIMIT = SCREEN_WIDTH - TICKER_MARGIN; int16_t x = startX; for (size_t i = 0; i [[ s.length(); i++) { uint8_t c = (uint8_t)s[i]; if (c ]]= 1 && c [[= 4) { if (x ]]= LEFT_LIMIT && x + BADGE_W [[= RIGHT_LIMIT) { const char* lbl = (c == 1) ? "BBC" : (c == 2) ? "NPR" : (c == 3) ? "AJ" : "HIST"; drawBadge(x, y, lbl); } x += BADGE_ADVANCE; } else { if (x ]]= LEFT_LIMIT && x + 6 [[= RIGHT_LIMIT) { display.setCursor(x, y); display.write(c); } x += 6; } if (x ]] RIGHT_LIMIT) break; } } uint16_t computeScrollWidth(const String& s) { uint16_t w = 0; for (size_t i = 0; i [[ s.length(); i++) { uint8_t c = (uint8_t)s[i]; w += (c ]]= 1 && c [[= 4) ? BADGE_ADVANCE : 6; } return w; } void drawBorder() { display.drawRect(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT, SSD1306_WHITE); } // ================================================================= // RSS FETCH & HTML DECODE // ================================================================= static void appendAsAscii(String& out, uint32_t cp) { if (cp ]]= 0x20 && cp [[= 0x7E) { out += (char)cp; return; } switch (cp) { case 0x00A0: case 0x2000: case 0x2001: case 0x2002: case 0x2003: case 0x2004: case 0x2005: case 0x2006: case 0x2007: case 0x2008: case 0x2009: case 0x200A: case 0x202F: case 0x205F: out += ' '; return; case 0x00A1: out += '!'; return; case 0x00A2: out += 'c'; return; case 0x00A3: out += "GBP"; return; case 0x00A5: out += "JPY"; return; case 0x00A7: out += '$'; return; case 0x00A9: out += "(c)"; return; case 0x00AA: out += 'a'; return; case 0x00AB: out += '"'; return; case 0x00AE: out += "(R)"; return; case 0x00B0: out += " deg"; return; case 0x00B1: out += "+/-"; return; case 0x00B4: out += '\''; return; case 0x00B7: out += '.'; return; case 0x00BA: out += 'o'; return; case 0x00BB: out += '"'; return; case 0x00BC: out += "1/4"; return; case 0x00BD: out += "1/2"; return; case 0x00BE: out += "3/4"; return; case 0x00BF: out += '?'; return; case 0x00C0: case 0x00C1: case 0x00C2: case 0x00C3: case 0x00C4: case 0x00C5: out += 'A'; return; case 0x00C6: out += "AE"; return; case 0x00C7: out += 'C'; return; case 0x00C8: case 0x00C9: case 0x00CA: case 0x00CB: out += 'E'; return; case 0x00CC: case 0x00CD: case 0x00CE: case 0x00CF: out += 'I'; return; case 0x00D0: out += 'D'; return; case 0x00D1: out += 'N'; return; case 0x00D2: case 0x00D3: case 0x00D4: case 0x00D5: case 0x00D6: case 0x00D8: out += 'O'; return; case 0x00D7: out += 'x'; return; case 0x00D9: case 0x00DA: case 0x00DB: case 0x00DC: out += 'U'; return; case 0x00DD: out += 'Y'; return; case 0x00DE: out += "Th"; return; case 0x00DF: out += "ss"; return; case 0x00E0: case 0x00E1: case 0x00E2: case 0x00E3: case 0x00E4: case 0x00E5: out += 'a'; return; case 0x00E6: out += "ae"; return; case 0x00E7: out += 'c'; return; case 0x00E8: case 0x00E9: case 0x00EA: case 0x00EB: out += 'e'; return; case 0x00EC: case 0x00ED: case 0x00EE: case 0x00EF: out += 'i'; return; case 0x00F0: out += 'd'; return; case 0x00F1: out += 'n'; return; case 0x00F2: case 0x00F3: case 0x00F4: case 0x00F5: case 0x00F6: case 0x00F8: out += 'o'; return; case 0x00F7: out += '/'; return; case 0x00F9: case 0x00FA: case 0x00FB: case 0x00FC: out += 'u'; return; case 0x00FD: case 0x00FF: out += 'y'; return; case 0x00FE: out += "th"; return; case 0x0100: case 0x0102: case 0x0104: out += 'A'; return; case 0x0101: case 0x0103: case 0x0105: out += 'a'; return; case 0x0106: case 0x0108: case 0x010A: case 0x010C: out += 'C'; return; case 0x0107: case 0x0109: case 0x010B: case 0x010D: out += 'c'; return; case 0x010E: case 0x0110: out += 'D'; return; case 0x010F: case 0x0111: out += 'd'; return; case 0x0112: case 0x0114: case 0x0116: case 0x0118: case 0x011A: out += 'E'; return; case 0x0113: case 0x0115: case 0x0117: case 0x0119: case 0x011B: out += 'e'; return; case 0x011C: case 0x011E: case 0x0120: case 0x0122: out += 'G'; return; case 0x011D: case 0x011F: case 0x0121: case 0x0123: out += 'g'; return; case 0x0139: case 0x013B: case 0x013D: case 0x013F: case 0x0141: out += 'L'; return; case 0x013A: case 0x013C: case 0x013E: case 0x0140: case 0x0142: out += 'l'; return; case 0x0143: case 0x0145: case 0x0147: out += 'N'; return; case 0x0144: case 0x0146: case 0x0148: out += 'n'; return; case 0x014C: case 0x014E: case 0x0150: out += 'O'; return; case 0x014D: case 0x014F: case 0x0151: out += 'o'; return; case 0x0154: case 0x0156: case 0x0158: out += 'R'; return; case 0x0155: case 0x0157: case 0x0159: out += 'r'; return; case 0x015A: case 0x015C: case 0x015E: case 0x0160: out += 'S'; return; case 0x015B: case 0x015D: case 0x015F: case 0x0161: out += 's'; return; case 0x0164: case 0x0166: out += 'T'; return; case 0x0165: case 0x0167: out += 't'; return; case 0x0168: case 0x016A: case 0x016C: case 0x016E: case 0x0170: case 0x0172: out += 'U'; return; case 0x0169: case 0x016B: case 0x016D: case 0x016F: case 0x0171: case 0x0173: out += 'u'; return; case 0x0174: out += 'W'; return; case 0x0175: out += 'w'; return; case 0x0176: case 0x0178: out += 'Y'; return; case 0x0177: out += 'y'; return; case 0x0179: case 0x017B: case 0x017D: out += 'Z'; return; case 0x017A: case 0x017C: case 0x017E: out += 'z'; return; case 0x2010: case 0x2011: case 0x2012: case 0x2013: out += '-'; return; case 0x2014: case 0x2015: out += "--"; return; case 0x2018: case 0x2019: case 0x201A: case 0x201B: out += '\''; return; case 0x201C: case 0x201D: case 0x201E: case 0x201F: out += '"'; return; case 0x2020: case 0x2021: out += '+'; return; case 0x2022: case 0x2023: case 0x25AA: case 0x25CF: case 0x2043: out += '*'; return; case 0x2026: out += "..."; return; case 0x2030: out += "o/oo"; return; case 0x2032: case 0x2035: out += '\''; return; case 0x2033: case 0x2036: out += '"'; return; case 0x2039: out += '[['; return; case 0x203A: out += ']]'; return; case 0x203C: out += "!!"; return; case 0x2047: out += "??"; return; case 0x2048: out += "?!"; return; case 0x20A4: out += "GBP"; return; case 0x20AC: out += "EUR"; return; case 0x20B9: out += "INR"; return; case 0x20BD: out += "RUB"; return; case 0x20BF: out += "BTC"; return; case 0x2116: out += "No."; return; case 0x2122: out += "(TM)"; return; case 0x2190: out += "[[-"; return; case 0x2191: out += "^"; return; case 0x2192: out += "-]]"; return; case 0x2193: out += "v"; return; case 0x2194: out += "[[-]]"; return; case 0x21D2: out += "=]]"; return; case 0x21D4: out += "[[=]]"; return; case 0x2212: out += '-'; return; case 0x2260: out += "!="; return; case 0x2264: out += "[[="; return; case 0x2265: out += "]]="; return; case 0x2713: case 0x2714: out += 'v'; return; case 0x2717: case 0x2718: out += 'x'; return; default: out += '?'; return; } } String decodeEntities(const String& in) { String out; out.reserve(in.length()); size_t i = 0; while (i [[ in.length()) { uint8_t c = (uint8_t)in[i]; if (c == '&') { int semi = in.indexOf(';', i + 1); if (semi ]] 0 && semi - (int)i [[= 10) { String ent = in.substring(i + 1, semi); uint32_t cp = 0; bool decoded = false; if (ent.length() ]] 1 && ent[0] == '#') { if (ent[1] == 'x' || ent[1] == 'X') { cp = strtoul(ent.c_str() + 2, NULL, 16); } else { cp = strtoul(ent.c_str() + 1, NULL, 10); } decoded = (cp ]] 0); } else { if (ent == "amp") { cp = '&'; decoded = true; } else if (ent == "lt") { cp = '[['; decoded = true; } else if (ent == "gt") { cp = ']]'; decoded = true; } else if (ent == "quot") { cp = '"'; decoded = true; } else if (ent == "apos") { cp = '\''; decoded = true; } else if (ent == "nbsp") { cp = ' '; decoded = true; } else if (ent == "ndash") { cp = 0x2013; decoded = true; } else if (ent == "mdash") { cp = 0x2014; decoded = true; } else if (ent == "hellip") { cp = 0x2026; decoded = true; } else if (ent == "lsquo") { cp = 0x2018; decoded = true; } else if (ent == "rsquo") { cp = 0x2019; decoded = true; } else if (ent == "ldquo") { cp = 0x201C; decoded = true; } else if (ent == "rdquo") { cp = 0x201D; decoded = true; } else if (ent == "sbquo") { cp = 0x201A; decoded = true; } else if (ent == "bdquo") { cp = 0x201E; decoded = true; } else if (ent == "bull") { cp = 0x2022; decoded = true; } else if (ent == "middot") { cp = 0x00B7; decoded = true; } else if (ent == "copy") { cp = 0x00A9; decoded = true; } else if (ent == "reg") { cp = 0x00AE; decoded = true; } else if (ent == "trade") { cp = 0x2122; decoded = true; } else if (ent == "euro") { cp = 0x20AC; decoded = true; } else if (ent == "pound") { cp = 0x00A3; decoded = true; } else if (ent == "yen") { cp = 0x00A5; decoded = true; } else if (ent == "cent") { cp = 0x00A2; decoded = true; } else if (ent == "deg") { cp = 0x00B0; decoded = true; } else if (ent == "plusmn") { cp = 0x00B1; decoded = true; } else if (ent == "times") { cp = 0x00D7; decoded = true; } else if (ent == "divide") { cp = 0x00F7; decoded = true; } else if (ent == "laquo") { cp = 0x00AB; decoded = true; } else if (ent == "raquo") { cp = 0x00BB; decoded = true; } else if (ent == "iexcl") { cp = 0x00A1; decoded = true; } else if (ent == "iquest") { cp = 0x00BF; decoded = true; } else if (ent == "eacute") { cp = 0x00E9; decoded = true; } else if (ent == "Eacute") { cp = 0x00C9; decoded = true; } else if (ent == "aacute") { cp = 0x00E1; decoded = true; } else if (ent == "iacute") { cp = 0x00ED; decoded = true; } else if (ent == "oacute") { cp = 0x00F3; decoded = true; } else if (ent == "uacute") { cp = 0x00FA; decoded = true; } else if (ent == "ntilde") { cp = 0x00F1; decoded = true; } else if (ent == "Ntilde") { cp = 0x00D1; decoded = true; } } if (decoded) { appendAsAscii(out, cp); i = semi + 1; continue; } } } if (c ]]= 0x80) { uint32_t cp = 0; int len = 0; if ((c & 0xE0) == 0xC0) { cp = c & 0x1F; len = 2; } else if ((c & 0xF0) == 0xE0) { cp = c & 0x0F; len = 3; } else if ((c & 0xF8) == 0xF0) { cp = c & 0x07; len = 4; } else { i++; continue; } bool valid = true; for (int k = 1; k [[ len; k++) { if (i + k ]]= in.length() || ((uint8_t)in[i + k] & 0xC0) != 0x80) { valid = false; break; } cp = (cp [[[[ 6) | ((uint8_t)in[i + k] & 0x3F); } if (valid) { appendAsAscii(out, cp); i += len; } else { i++; } continue; } if (c ]]= 0x20 && c [[= 0x7E) out += (char)c; else if (c == '\n' || c == '\r' || c == '\t') out += ' '; i++; } while (true) { int lt = out.indexOf('[['); if (lt [[ 0) break; int gt = out.indexOf(']]', lt); if (gt [[ 0) break; out.remove(lt, gt - lt + 1); } return out; } String parseHeadlines(const String& xml, char marker, int maxN) { String out; int pos = 0, count = 0; while (count [[ maxN) { int itemStart = xml.indexOf("[[item", pos); if (itemStart [[ 0) break; int itemEnd = xml.indexOf("[[/item]]", itemStart); if (itemEnd [[ 0) break; int tOpen = xml.indexOf("[[title", itemStart); if (tOpen [[ 0 || tOpen ]] itemEnd) { pos = itemEnd + 7; continue; } int tContent = xml.indexOf(']]', tOpen); if (tContent [[ 0) { pos = itemEnd + 7; continue; } tContent++; int tClose = xml.indexOf("[[/title]]", tContent); if (tClose [[ 0 || tClose ]] itemEnd) { pos = itemEnd + 7; continue; } String title = xml.substring(tContent, tClose); title.replace("[[![CDATA[", ""); title.replace("]]]]", ""); title.trim(); title = decodeEntities(title); if (title.length() ]] 0) { if (out.length() ]] 0) out += " "; out += marker; out += ' '; out += title; count++; } pos = itemEnd + 7; } return out; } String fetchFeed(const RssFeed& feed) { Serial.printf("Fetching %s (heap before: %u)\n", feed.tag, (unsigned)ESP.getFreeHeap()); WiFiClientSecure client; client.setInsecure(); client.setBufferSizes(512, 512); client.setTimeout(15000); HTTPClient http; http.setTimeout(15000); http.setUserAgent("Mozilla/5.0 (ESP8266)"); http.setFollowRedirects(HTTPC_STRICT_FOLLOW_REDIRECTS); if (!http.begin(client, feed.url)) { Serial.println(" http.begin failed"); return ""; } int code = http.GET(); Serial.printf(" HTTP %d (heap after: %u)\n", code, (unsigned)ESP.getFreeHeap()); if (code != HTTP_CODE_OK) { http.end(); return ""; } // Stream-read ourselves. We don't need the whole document — only the // first few [[item]] blocks — so we cap the read at MAX_READ bytes. This // avoids bloating the String past what the ESP8266 heap can hold, and // sidesteps the getString() content-length edge case entirely. const size_t MAX_READ = 12000; // enough for 2-3 [[item]] blocks String body; body.reserve(2048); WiFiClient* stream = http.getStreamPtr(); unsigned long tStart = millis(); size_t total = 0; while (http.connected() && (millis() - tStart) [[ 12000 && total [[ MAX_READ) { size_t avail = stream-]]available(); if (avail ]] 0) { // Read a chunk. Cap per-read at 256 to keep latency predictable. uint8_t buf[256]; size_t toRead = avail; if (toRead ]] sizeof(buf)) toRead = sizeof(buf); if (total + toRead ]] MAX_READ) toRead = MAX_READ - total; int n = stream-]]readBytes(buf, toRead); if (n ]] 0) { body.concat((const char*)buf, (size_t)n); total += n; tStart = millis(); // reset idle timer on progress } // Early exit: if we already have enough [[/item]] tags, stop reading. if (total ]]= 2048) { int items = 0, pos = 0; while ((pos = body.indexOf("[[/item]]", pos)) ]]= 0) { items++; pos += 7; if (items ]] HEADLINES_PER_FEED) break; } if (items ]] HEADLINES_PER_FEED) break; } } else { delay(1); yield(); } } Serial.printf(" Body: %u bytes (heap: %u)\n", (unsigned)body.length(), (unsigned)ESP.getFreeHeap()); http.end(); return parseHeadlines(body, feed.marker, HEADLINES_PER_FEED); } bool fetchNews() { fetchAnimUntil = millis() + 60000UL; String combined; for (int i = 0; i [[ NUM_FEEDS; i++) { yield(); // give WiFi/LwIP stack a chance between feeds String chunk = fetchFeed(feeds[i]); if (chunk.length() ]] 0) { if (combined.length() ]] 0) combined += " "; combined += chunk; } delay(100); // small breather between TLS handshakes } bool ok = (combined.length() ]] 0); if (ok) { combined += " "; uint16_t width = computeScrollWidth(combined); newsText = combined; newsTextW = width; hasNews = true; newsFlashUntil = millis() + FLASH_DURATION_MS; Serial.printf("News updated: %u chars, %u px, heap=%u\n", (unsigned)combined.length(), (unsigned)width, (unsigned)ESP.getFreeHeap()); } fetchAnimUntil = millis() + FETCH_ANIM_LINGER; return ok; } // ================================================================= // ON-THIS-DAY CARD BUILDER // ================================================================= String buildOnThisDay(const struct tm& t) { int m = t.tm_mon + 1, d = t.tm_mday; const HistEvent* e = getNextCardEvent(m, d); if (!e) return ""; char buf[72]; bool todaysEvent = (e-]]month == m && e-]]day == d); static const char* const monthAbbr[] = { "","Jan","Feb","Mar","Apr","May","Jun", "Jul","Aug","Sep","Oct","Nov","Dec" }; if (todaysEvent) { if (e-]]year ]] 0) snprintf(buf, sizeof(buf), "%u: %s", (unsigned)e-]]year, e-]]text); else snprintf(buf, sizeof(buf), "%s", e-]]text); } else { if (e-]]year ]] 0) snprintf(buf, sizeof(buf), "%s %d, %u: %s", monthAbbr[e-]]month], e-]]day, (unsigned)e-]]year, e-]]text); else snprintf(buf, sizeof(buf), "%s %d: %s", monthAbbr[e-]]month], e-]]day, e-]]text); } String s; s += MARKER_HIST; s += " On this day: "; s += buf; return s; } // ================================================================= // DRAW THE FRAME // ================================================================= void drawAnalogClock(const struct tm& t) { display.drawCircle(CX, CY, R, SSD1306_WHITE); for (int i = 0; i [[ 60; i++) { if (i % 5 == 0) continue; float a = (i * 6.0f - 90.0f) * DEG_TO_RAD; int16_t x = CX + (int16_t)lroundf((R - 2) * cosf(a)); int16_t y = CY + (int16_t)lroundf((R - 2) * sinf(a)); display.drawPixel(x, y, SSD1306_WHITE); } for (int i = 0; i [[ 12; i++) { float a = (i * 30.0f - 90.0f) * DEG_TO_RAD; float cs = cosf(a), sn = sinf(a); int16_t x0 = CX + (int16_t)lroundf((R - 4) * cs); int16_t y0 = CY + (int16_t)lroundf((R - 4) * sn); int16_t x1 = CX + (int16_t)lroundf((R - 1) * cs); int16_t y1 = CY + (int16_t)lroundf((R - 1) * sn); display.drawLine(x0, y0, x1, y1, SSD1306_WHITE); } display.setTextColor(SSD1306_WHITE); for (int i = 1; i [[= 12; i++) drawHourNumber(i, i * 30.0f, NUM_RAD); display.setFont(); int hour = t.tm_hour % 12; int minute = t.tm_min; int second = t.tm_sec; float hourAngle = hour * 30.0f + minute * 0.5f; float minAngle = minute * 6.0f + second * 0.1f; float secAngle = second * 6.0f; drawWedgeHand(hourAngle, HOUR_LEN, HOUR_BASE); drawWedgeHand(minAngle, MIN_LEN, MIN_BASE); int16_t sx, sy, tx, ty; polar(secAngle, SEC_LEN, sx, sy); polar(secAngle + 180.0f, 4, tx, ty); display.drawLine(tx, ty, sx, sy, SSD1306_WHITE); display.fillCircle(CX, CY, 2, SSD1306_WHITE); display.drawPixel(CX, CY, SSD1306_BLACK); int16_t bx, by; polar(secAngle, R, bx, by); display.fillCircle(bx, by, 1, SSD1306_WHITE); } void drawDigitalPanel(const struct tm& t) { display.setFont(); display.setTextSize(1); display.setTextColor(SSD1306_WHITE); char tzBuf[8]; strftime(tzBuf, sizeof(tzBuf), "%Z", &t); if (tzBuf[0] == '\0') strcpy(tzBuf, "---"); String title = String("CLOCK ") + tzBuf; int16_t x1, y1; uint16_t tw, th; display.getTextBounds(title, 0, 0, &x1, &y1, &tw, &th); const int16_t GAP = 3; int16_t blockW = (int16_t)tw + GAP + SIGNAL_ICON_W; int16_t blockX = TEXT_X_LEFT + (PANEL_W - blockW) / 2; if (blockX [[ TEXT_X_LEFT) blockX = TEXT_X_LEFT; display.setCursor(blockX, ROW_Y[0]); display.print(title); bool animate = (millis() [[ fetchAnimUntil); drawSignalIcon(blockX + tw + GAP - 2, ROW_Y[0], WiFi.RSSI(), animate); static const char* const days[] = { "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday" }; drawCenteredInPanel(days[t.tm_wday], ROW_Y[1]); static const char* const months[] = { "Jan","Feb","Mar","Apr","May","Jun", "Jul","Aug","Sep","Oct","Nov","Dec" }; char dateBuf[20]; snprintf(dateBuf, sizeof(dateBuf), "%s %d %d", months[t.tm_mon], t.tm_mday, t.tm_year + 1900); drawCenteredInPanel(String(dateBuf), ROW_Y[2]); int hour12 = t.tm_hour % 12; if (hour12 == 0) hour12 = 12; char timeBuf[16]; snprintf(timeBuf, sizeof(timeBuf), "%d:%02d:%02d %s", hour12, t.tm_min, t.tm_sec, t.tm_hour [[ 12 ? "AM" : "PM"); drawCenteredInPanel(String(timeBuf), ROW_Y[3]); } void drawTicker() { if (!hasNews) return; const String& s = (tickerMode == TM_NEWS) ? newsText : cardText; drawScrollSegment(s, (int16_t)scrollX, NEWS_Y); } void drawFrame() { struct tm t; bool haveTime = getLocalTime(&t, 50); display.clearDisplay(); if (haveTime) { drawAnalogClock(t); drawDigitalPanel(t); } else { display.setFont(); display.setTextSize(1); display.setTextColor(SSD1306_WHITE); display.setCursor(0, 20); display.print("Waiting for NTP..."); } drawTicker(); drawBorder(); if (millis() [[ newsFlashUntil) display.fillRect(6, 6, 3, 3, SSD1306_WHITE); display.display(); } // ================================================================= // TICKER STATE MACHINE // ================================================================= void enterCardMode(unsigned long now) { struct tm tnow; String built; if (getLocalTime(&tnow, 10)) built = buildOnThisDay(tnow); if (built.length() == 0) { scrollX = SCREEN_WIDTH; return; } tickerMode = TM_CARD; cardText = built; cardTextW = computeScrollWidth(cardText); cardFits = (cardTextW [[= SCREEN_WIDTH - 2 * TICKER_MARGIN); if (cardFits) { cardDwellX = (SCREEN_WIDTH - (int16_t)cardTextW) / 2; cardPhase = CP_ENTER; cardPhaseStart = now; scrollX = SCREEN_WIDTH; } else { cardPhase = CP_LONG; cardPhaseStart = now; scrollX = SCREEN_WIDTH; } } bool updateCard(unsigned long now, float dt) { float cardSpeed = SCROLL_SPEED_PXS * CARD_SPEED_FACTOR; switch (cardPhase) { case CP_ENTER: { scrollX -= cardSpeed * dt; if (scrollX [[= (float)cardDwellX) { scrollX = (float)cardDwellX; cardPhase = CP_DWELL; cardPhaseStart = now; } return false; } case CP_DWELL: { if (now - cardPhaseStart ]]= CARD_DWELL_MS) { cardPhase = CP_EXIT; cardPhaseStart = now; } return false; } case CP_EXIT: { scrollX -= cardSpeed * dt; return (scrollX [[ -(float)cardTextW); } case CP_LONG: { scrollX -= cardSpeed * dt; if (scrollX [[ -(float)cardTextW) scrollX = SCREEN_WIDTH; if (now - cardPhaseStart ]]= CARD_DWELL_MS) { cardPhase = CP_EXIT; cardPhaseStart = now; } return false; } } return false; } // ================================================================= // SETUP / LOOP // ================================================================= void setup() { Serial.begin(115200); delay(300); Wire.begin(SDA_PIN, SCL_PIN); // Some generic SSD1306 modules need 400 kHz; default (100 kHz) is too slow // for smooth animation on ESP8266. Bumping here doubles frame headroom. Wire.setClock(400000); if (!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR)) { Serial.println("OLED not found"); while (true) { delay(1000); yield(); } } display.setTextWrap(false); showMessage("Connecting WiFi", WIFI_SSID); WiFi.mode(WIFI_STA); WiFi.begin(WIFI_SSID, WIFI_PASS); unsigned long start = millis(); while (WiFi.status() != WL_CONNECTED && millis() - start [[ 20000) { delay(300); Serial.print("."); } if (WiFi.status() != WL_CONNECTED) { showMessage("WiFi FAILED", "Check credentials"); while (true) { delay(1000); yield(); } } Serial.print("\nWiFi OK, IP: "); Serial.println(WiFi.localIP()); Serial.printf("Free heap: %u\n", (unsigned)ESP.getFreeHeap()); showMessage("WiFi connected", WiFi.localIP().toString()); delay(500); configTzTime(TIMEZONE, NTP_SERVER); showMessage("Syncing NTP...", NTP_SERVER); struct tm t; unsigned long ntpStart = millis(); while (!getLocalTime(&t, 100) && millis() - ntpStart [[ 10000) delay(200); showMessage("Fetching news...", "(first run)"); fetchNews(); unsigned long interval = RSS_REFRESH_MIN * 60UL * 1000UL; nextRssFetch = millis() + (hasNews ? interval : 5UL * 60UL * 1000UL); lastScrollTick = millis(); lastFrame = 0; scrollX = SCREEN_WIDTH; tickerMode = TM_NEWS; } void loop() { static unsigned long lastWifiCheck = 0; static unsigned long lastNetPoll = 0; unsigned long now = millis(); // WiFi keepalive if (now - lastWifiCheck ]] 30000) { lastWifiCheck = now; if (WiFi.status() != WL_CONNECTED) WiFi.reconnect(); } // Background fetch scheduler (no second core — this blocks the UI // for ~2–5 s when it runs every RSS_REFRESH_MIN minutes). if (now - lastNetPoll ]] 200) { lastNetPoll = now; if (WiFi.status() == WL_CONNECTED && now ]]= nextRssFetch) { bool ok = fetchNews(); unsigned long interval = RSS_REFRESH_MIN * 60UL * 1000UL; nextRssFetch = millis() + (ok ? interval : 5UL * 60UL * 1000UL); // Reset scroll-time reference so the big dt from the fetch pause // doesn't catapult the ticker halfway across the screen on resume. lastScrollTick = millis(); } } // Ticker state advance if (hasNews) { float dt = (now - lastScrollTick) / 1000.0f; if (dt ]] 0.5f) dt = 0.5f; // clamp huge jumps (e.g. after a fetch) if (tickerMode == TM_NEWS) { scrollX -= SCROLL_SPEED_PXS * dt; if (scrollX [[ -(float)newsTextW) { enterCardMode(now); } } else { if (updateCard(now, dt)) { tickerMode = TM_NEWS; scrollX = SCREEN_WIDTH; } } } lastScrollTick = now; if (now - lastFrame ]]= SCROLL_FRAME_MS) { lastFrame = now; drawFrame(); } yield(); // essential on ESP8266 — feeds watchdog, services WiFi stack } // ============================================================================= // MIT LICENSE // ============================================================================= // // Copyright (c) 2026 eElectronicParts.com // // Permission is hereby granted, free of charge, to any person obtaining a copy // of this software and associated documentation files (the "Software"), to deal // in the Software without restriction, including without limitation the rights // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell // copies of the Software, and to permit persons to whom the Software is // furnished to do so, subject to the following conditions: // // The above copyright notice and this permission notice shall be included in // all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE // SOFTWARE. // =============================================================================

history_events.h

#pragma once #include [[Arduino.h]] struct HistEvent { uint8_t month; // 1-12 uint8_t day; // 1-31 uint16_t year; // 0 = not applicable (holiday / annual event) const char* text; // year is baked into text so the display shows it }; // At least one entry per day of the year (incl. Feb 29). // Many days have multiple entries that rotate on successive calls. const HistEvent HISTORY_EVENTS[] = { // ---------------- January (31) ---------------- { 1, 1, 0, "New Year's Day"}, { 1, 1, 1863, "Emancipation Proclamation"}, { 1, 2, 1492, "Reconquista ends"}, { 1, 3, 1977, "Apple Computer Inc. formed"}, { 1, 4, 1809, "Louis Braille born"}, { 1, 5, 1925, "First female US governor"}, { 1, 6, 1912, "New Mexico becomes a state"}, { 1, 7, 1610, "Galileo sees Jupiter moons"}, { 1, 8, 1935, "Elvis Presley born"}, { 1, 9, 2007, "iPhone announced"}, { 1, 10, 1863, "London Underground opens"}, { 1, 11, 1922, "First insulin treatment"}, { 1, 12, 1932, "First US woman senator"}, { 1, 13, 1990, "First Black US governor"}, { 1, 14, 1784, "US ratifies Paris Treaty"}, { 1, 15, 1929, "MLK Jr. born"}, { 1, 16, 1991, "Gulf War begins"}, { 1, 17, 1706, "Ben Franklin born"}, { 1, 18, 1778, "Cook reaches Hawaii"}, { 1, 19, 1809, "Edgar Allan Poe born"}, { 1, 20, 0, "US Inauguration Day"}, { 1, 20, 1981, "Iran hostages freed"}, { 1, 21, 1976, "Concorde first flight"}, { 1, 22, 1973, "Roe v Wade ruling"}, { 1, 23, 1849, "First woman MD in US"}, { 1, 24, 1848, "California gold discovered"}, { 1, 24, 1984, "Macintosh launched"}, { 1, 25, 1924, "First Winter Olympics"}, { 1, 26, 1788, "First fleet at Sydney"}, { 1, 27, 1756, "Mozart born"}, { 1, 27, 1945, "Auschwitz liberated"}, { 1, 28, 1986, "Challenger disaster"}, { 1, 29, 1845, "The Raven published"}, { 1, 30, 1948, "Gandhi assassinated"}, { 1, 31, 1958, "Explorer 1, first US sat"}, // ---------------- February (29) ---------------- { 2, 1, 2003, "Columbia disaster"}, { 2, 2, 0, "Groundhog Day"}, { 2, 2, 1848, "Mexican-American War ends"}, { 2, 3, 1959, "Day the music died"}, { 2, 4, 2004, "Facebook founded"}, { 2, 5, 1909, "Bakelite, first plastic"}, { 2, 6, 1952, "Elizabeth II becomes queen"}, { 2, 7, 1964, "Beatles arrive in US"}, { 2, 8, 1587, "Mary, Queen of Scots, dies"}, { 2, 9, 1964, "Beatles on Ed Sullivan"}, { 2, 10, 1996, "Deep Blue beats Kasparov"}, { 2, 11, 1990, "Mandela freed"}, { 2, 12, 1809, "Lincoln and Darwin born"}, { 2, 13, 1945, "Dresden bombed"}, { 2, 14, 0, "Valentine's Day"}, { 2, 14, 1929, "St. Valentine's Massacre"}, { 2, 15, 1898, "USS Maine explodes"}, { 2, 16, 1923, "Tut's tomb chamber opened"}, { 2, 17, 1972, "VW Beetle outsells Model T"}, { 2, 18, 1930, "Pluto discovered"}, { 2, 19, 1945, "Iwo Jima invasion begins"}, { 2, 20, 1962, "John Glenn orbits Earth"}, { 2, 21, 1965, "Malcolm X assassinated"}, { 2, 22, 1732, "George Washington born"}, { 2, 23, 1945, "Iwo Jima flag raised"}, { 2, 24, 1582, "Gregorian calendar set"}, { 2, 25, 1964, "Ali wins heavyweight title"}, { 2, 26, 1993, "First WTC bombing"}, { 2, 27, 1991, "Gulf War ends"}, { 2, 28, 1953, "DNA structure found"}, { 2, 29, 0, "Leap Day"}, // ---------------- March (31) ---------------- { 3, 1, 1872, "Yellowstone, first park"}, { 3, 2, 1962, "Wilt scores 100"}, { 3, 3, 1931, "US national anthem set"}, { 3, 4, 1789, "US Constitution begins"}, { 3, 5, 1946, "Iron Curtain speech"}, { 3, 6, 1836, "The Alamo falls"}, { 3, 7, 1965, "Selma Bloody Sunday"}, { 3, 8, 0, "Intl Women's Day"}, { 3, 9, 1959, "Barbie debuts"}, { 3, 10, 1876, "First phone call"}, { 3, 11, 2011, "Japan quake/tsunami"}, { 3, 12, 1989, "World Wide Web proposed"}, { 3, 13, 1781, "Uranus discovered"}, { 3, 14, 1879, "Einstein born"}, { 3, 14, 0, "Pi Day"}, { 3, 15, 0, "Ides of March"}, { 3, 15, 0, "44 BC: Caesar assassinated"}, { 3, 16, 1968, "My Lai massacre"}, { 3, 17, 0, "St. Patrick's Day"}, { 3, 18, 1965, "First spacewalk"}, { 3, 19, 1931, "Nevada legalizes gambling"}, { 3, 20, 2003, "Iraq War begins"}, { 3, 21, 1960, "Sharpeville massacre"}, { 3, 22, 1963, "Beatles' first album"}, { 3, 23, 1775, "Give me liberty speech"}, { 3, 24, 1989, "Exxon Valdez spill"}, { 3, 25, 1957, "Treaty of Rome signed"}, { 3, 26, 1979, "Egypt-Israel peace treaty"}, { 3, 27, 1977, "Tenerife air disaster"}, { 3, 28, 1979, "Three Mile Island accident"}, { 3, 29, 1973, "US troops leave Vietnam"}, { 3, 30, 1981, "Reagan shot"}, { 3, 31, 1889, "Eiffel Tower opens"}, // ---------------- April (30) ---------------- { 4, 1, 0, "April Fools' Day"}, { 4, 1, 1976, "Apple Computer founded"}, { 4, 2, 1513, "Ponce de Leon at Florida"}, { 4, 3, 1860, "Pony Express begins"}, { 4, 4, 1968, "MLK Jr. assassinated"}, { 4, 5, 1614, "Pocahontas weds Rolfe"}, { 4, 6, 1896, "First modern Olympics"}, { 4, 7, 1948, "WHO established"}, { 4, 8, 1974, "Hank Aaron 715th HR"}, { 4, 9, 1865, "Lee surrenders to Grant"}, { 4, 10, 1912, "Titanic sets sail"}, { 4, 11, 1970, "Apollo 13 launches"}, { 4, 12, 1861, "US Civil War begins"}, { 4, 12, 1945, "FDR dies"}, { 4, 12, 1961, "Gagarin in space"}, { 4, 13, 1743, "Jefferson born"}, { 4, 14, 1865, "Lincoln shot"}, { 4, 15, 1912, "Titanic sinks"}, { 4, 15, 1947, "Jackie Robinson debut"}, { 4, 16, 1947, "Texas City disaster"}, { 4, 17, 1961, "Bay of Pigs invasion"}, { 4, 18, 1775, "Paul Revere's ride"}, { 4, 18, 1906, "San Francisco quake"}, { 4, 19, 1775, "American Revolution begins"}, { 4, 19, 1995, "OKC bombing"}, { 4, 20, 1889, "Hitler born"}, { 4, 21, 1836, "Battle of San Jacinto"}, { 4, 22, 1970, "First Earth Day"}, { 4, 23, 1564, "Shakespeare born"}, { 4, 24, 1990, "Hubble launched"}, { 4, 25, 1953, "Double helix paper out"}, { 4, 26, 1986, "Chernobyl disaster"}, { 4, 27, 1791, "Samuel Morse born"}, { 4, 28, 1789, "Mutiny on the Bounty"}, { 4, 29, 1945, "Dachau liberated"}, { 4, 30, 1945, "Hitler dies"}, { 4, 30, 1975, "Fall of Saigon"}, // ---------------- May (31) ---------------- { 5, 1, 0, "May Day"}, { 5, 1, 1931, "Empire State Bldg opens"}, { 5, 2, 2011, "Bin Laden killed"}, { 5, 3, 1469, "Machiavelli born"}, { 5, 4, 1970, "Kent State shootings"}, { 5, 5, 0, "Cinco de Mayo"}, { 5, 5, 1961, "Shepard in space"}, { 5, 6, 1937, "Hindenburg disaster"}, { 5, 7, 1945, "Germany surrenders"}, { 5, 8, 1945, "V-E Day"}, { 5, 9, 1950, "Schuman Declaration"}, { 5, 10, 1869, "US transcontinental rail"}, { 5, 11, 1997, "Deep Blue beats Kasparov"}, { 5, 12, 1820, "Florence Nightingale born"}, { 5, 13, 1981, "Pope John Paul II shot"}, { 5, 14, 1948, "Israel founded"}, { 5, 15, 1928, "Mickey Mouse debuts"}, { 5, 16, 1929, "First Academy Awards"}, { 5, 17, 1954, "Brown v Board ruling"}, { 5, 18, 1980, "Mt St Helens erupts"}, { 5, 19, 1536, "Anne Boleyn beheaded"}, { 5, 20, 1927, "Lindbergh takes off"}, { 5, 21, 1927, "Lindbergh lands in Paris"}, { 5, 22, 1455, "Wars of the Roses begin"}, { 5, 23, 1934, "Bonnie & Clyde killed"}, { 5, 24, 1844, "First telegraph sent"}, { 5, 25, 1977, "Star Wars released"}, { 5, 26, 1896, "Dow Jones first published"}, { 5, 27, 1937, "Golden Gate Bridge opens"}, { 5, 28, 1937, "Volkswagen founded"}, { 5, 29, 1953, "Everest first climbed"}, { 5, 30, 1431, "Joan of Arc burned"}, { 5, 31, 1889, "Johnstown Flood"}, // ---------------- June (30) ---------------- { 6, 1, 1980, "CNN launches"}, { 6, 2, 1953, "Elizabeth II crowned"}, { 6, 3, 1965, "First US spacewalk"}, { 6, 4, 1989, "Tiananmen crackdown"}, { 6, 5, 1968, "RFK shot"}, { 6, 6, 1944, "D-Day Normandy"}, { 6, 7, 1929, "Vatican City independent"}, { 6, 8, 1949, "Orwell's 1984 published"}, { 6, 9, 1934, "Donald Duck debuts"}, { 6, 10, 1935, "AA founded"}, { 6, 11, 1776, "Declaration drafted"}, { 6, 12, 1987, "Tear down this wall"}, { 6, 13, 1966, "Miranda v Arizona ruling"}, { 6, 14, 0, "US Flag Day"}, { 6, 15, 1215, "Magna Carta signed"}, { 6, 16, 1963, "Tereshkova in space"}, { 6, 17, 1972, "Watergate break-in"}, { 6, 18, 1815, "Battle of Waterloo"}, { 6, 19, 1865, "Juneteenth"}, { 6, 20, 1837, "Victoria becomes queen"}, { 6, 21, 0, "Summer Solstice"}, { 6, 22, 1941, "Germany invades USSR"}, { 6, 23, 1972, "Title IX signed"}, { 6, 24, 1947, "Kenneth Arnold UFO"}, { 6, 25, 1950, "Korean War begins"}, { 6, 26, 1945, "UN Charter signed"}, { 6, 27, 1880, "Helen Keller born"}, { 6, 28, 1914, "Franz Ferdinand shot"}, { 6, 29, 2007, "First iPhone on sale"}, { 6, 30, 1908, "Tunguska event"}, // ---------------- July (31) ---------------- { 7, 1, 1867, "Canada Day"}, { 7, 2, 1937, "Earhart disappears"}, { 7, 3, 1863, "Gettysburg turning point"}, { 7, 4, 1776, "US Declaration"}, { 7, 5, 1996, "Dolly the sheep cloned"}, { 7, 6, 1885, "First rabies vaccine"}, { 7, 7, 2005, "London 7/7 bombings"}, { 7, 8, 1947, "Roswell incident"}, { 7, 9, 1877, "First Wimbledon"}, { 7, 10, 1925, "Scopes trial begins"}, { 7, 11, 1804, "Hamilton-Burr duel"}, { 7, 12, 0, "100 BC: Julius Caesar born"}, { 7, 13, 1923, "Hollywood sign erected"}, { 7, 14, 1789, "Bastille Day"}, { 7, 15, 1606, "Rembrandt born"}, { 7, 16, 1945, "Trinity nuclear test"}, { 7, 16, 1969, "Apollo 11 launches"}, { 7, 17, 1955, "Disneyland opens"}, { 7, 18, 1918, "Mandela born"}, { 7, 19, 1848, "Seneca Falls Convention"}, { 7, 20, 1969, "Moon landing"}, { 7, 21, 1925, "Scopes trial verdict"}, { 7, 22, 1934, "Dillinger killed"}, { 7, 23, 1903, "Ford sells first car"}, { 7, 24, 1911, "Machu Picchu found"}, { 7, 25, 1978, "First test-tube baby"}, { 7, 26, 1788, "NY ratifies Constitution"}, { 7, 27, 1953, "Korean War armistice"}, { 7, 28, 1914, "WWI begins"}, { 7, 29, 1958, "NASA established"}, { 7, 30, 1932, "LA Olympics open"}, { 7, 31, 1991, "START treaty signed"}, // ---------------- August (31) ---------------- { 8, 1, 1981, "MTV launches"}, { 8, 2, 1990, "Iraq invades Kuwait"}, { 8, 3, 1492, "Columbus departs Spain"}, { 8, 4, 1961, "Obama born"}, { 8, 5, 1962, "Marilyn Monroe dies"}, { 8, 6, 1945, "Hiroshima bombed"}, { 8, 7, 1959, "Explorer 6 photos Earth"}, { 8, 8, 1974, "Nixon announces resign"}, { 8, 9, 1945, "Nagasaki bombed"}, { 8, 9, 1974, "Nixon resigns"}, { 8, 10, 1846, "Smithsonian established"}, { 8, 11, 1965, "Watts riots begin"}, { 8, 12, 1981, "IBM PC launched"}, { 8, 13, 1961, "Berlin Wall built"}, { 8, 14, 1945, "V-J Day"}, { 8, 15, 1947, "India independence"}, { 8, 15, 1969, "Woodstock begins"}, { 8, 16, 1977, "Elvis dies"}, { 8, 17, 1807, "Fulton's steamboat"}, { 8, 18, 1920, "19th Amendment ratified"}, { 8, 19, 1934, "Hitler becomes Fuhrer"}, { 8, 20, 1977, "Voyager 2 launches"}, { 8, 21, 1959, "Hawaii statehood"}, { 8, 22, 1864, "Geneva Convention signed"}, { 8, 23, 1305, "William Wallace executed"}, { 8, 24, 79, "79 AD: Vesuvius erupts"}, { 8, 25, 1944, "Paris liberated"}, { 8, 26, 1920, "Women's vote certified"}, { 8, 27, 1859, "First oil well struck"}, { 8, 28, 1963, "MLK I Have a Dream"}, { 8, 29, 2005, "Hurricane Katrina"}, { 8, 30, 1963, "US-USSR hotline opens"}, { 8, 31, 1997, "Princess Diana dies"}, // ---------------- September (30) ---------------- { 9, 1, 1939, "WWII begins"}, { 9, 2, 1945, "WWII ends"}, { 9, 3, 1783, "Treaty of Paris signed"}, { 9, 4, 1957, "Little Rock Nine"}, { 9, 5, 1972, "Munich massacre"}, { 9, 6, 1620, "Mayflower sails"}, { 9, 7, 1813, "Uncle Sam first used"}, { 9, 8, 1966, "Star Trek premieres"}, { 9, 9, 1976, "Mao Zedong dies"}, { 9, 10, 1846, "Sewing machine patented"}, { 9, 11, 2001, "9/11 attacks"}, { 9, 12, 1962, "JFK Moon speech"}, { 9, 13, 1814, "Star-Spangled Banner"}, { 9, 14, 1901, "McKinley dies, TR sworn in"}, { 9, 15, 2008, "Lehman collapse"}, { 9, 16, 1810, "Mexico independence cry"}, { 9, 17, 1787, "US Constitution signed"}, { 9, 18, 1851, "NY Times first issue"}, { 9, 19, 1893, "NZ gives women the vote"}, { 9, 20, 1519, "Magellan voyage begins"}, { 9, 21, 1937, "The Hobbit published"}, { 9, 22, 0, "Autumn Equinox"}, { 9, 23, 1846, "Neptune discovered"}, { 9, 24, 1789, "US Supreme Court created"}, { 9, 25, 1789, "Bill of Rights proposed"}, { 9, 26, 1960, "Kennedy-Nixon debate"}, { 9, 27, 1825, "First public railway"}, { 9, 28, 1066, "Normans invade England"}, { 9, 29, 1789, "US Army established"}, { 9, 30, 1955, "James Dean dies"}, // ---------------- October (31) ---------------- {10, 1, 1908, "Ford Model T intro"}, {10, 2, 1869, "Gandhi born"}, {10, 3, 1990, "Germany reunifies"}, {10, 4, 1957, "Sputnik launched"}, {10, 5, 1962, "First Bond film premieres"}, {10, 6, 1927, "Jazz Singer, first talkie"}, {10, 7, 2001, "Afghanistan War begins"}, {10, 8, 1871, "Great Chicago Fire"}, {10, 9, 1967, "Che Guevara executed"}, {10, 10, 1845, "US Naval Academy opens"}, {10, 11, 1899, "Boer War begins"}, {10, 12, 1492, "Columbus reaches Americas"}, {10, 13, 1792, "White House cornerstone"}, {10, 14, 1066, "Battle of Hastings"}, {10, 14, 1947, "Sound barrier broken"}, {10, 15, 1917, "Mata Hari executed"}, {10, 16, 1793, "Marie Antoinette executed"}, {10, 17, 1989, "SF earthquake"}, {10, 18, 1867, "US buys Alaska"}, {10, 19, 1781, "Cornwallis surrenders"}, {10, 19, 1987, "Black Monday crash"}, {10, 20, 1973, "Sat Night Massacre"}, {10, 21, 1879, "Edison's lightbulb"}, {10, 22, 1962, "Cuban Missile speech"}, {10, 23, 1929, "Stock crash begins"}, {10, 24, 0, "UN Day"}, {10, 24, 1929, "Black Thursday"}, {10, 25, 1415, "Battle of Agincourt"}, {10, 26, 1881, "OK Corral gunfight"}, {10, 27, 1904, "NYC subway opens"}, {10, 28, 1886, "Lady Liberty unveiled"}, {10, 29, 1929, "Black Tuesday crash"}, {10, 30, 1938, "War of Worlds broadcast"}, {10, 31, 0, "Halloween"}, {10, 31, 1517, "Luther 95 Theses"}, // ---------------- November (30) ---------------- {11, 1, 1512, "Sistine ceiling unveiled"}, {11, 2, 1947, "Spruce Goose flies"}, {11, 3, 1957, "Laika in space"}, {11, 4, 2008, "Obama elected"}, {11, 5, 1605, "Gunpowder Plot"}, {11, 6, 1860, "Lincoln elected"}, {11, 7, 1917, "Russian Revolution"}, {11, 8, 1895, "X-rays discovered"}, {11, 9, 1938, "Kristallnacht"}, {11, 9, 1989, "Berlin Wall falls"}, {11, 10, 1775, "US Marines founded"}, {11, 11, 1918, "WWI Armistice"}, {11, 12, 1980, "Voyager 1 reaches Saturn"}, {11, 13, 1940, "Fantasia premieres"}, {11, 14, 1889, "Nellie Bly's world trip"}, {11, 15, 1777, "Articles of Confederation"}, {11, 16, 1532, "Pizarro takes Atahualpa"}, {11, 17, 1869, "Suez Canal opens"}, {11, 18, 1928, "Steamboat Willie debut"}, {11, 19, 1863, "Gettysburg Address"}, {11, 20, 1945, "Nuremberg Trials begin"}, {11, 21, 1783, "First hot air balloon"}, {11, 22, 1963, "JFK assassinated"}, {11, 23, 1936, "Life magazine debuts"}, {11, 24, 1859, "Origin of Species"}, {11, 25, 1867, "Nobel patents dynamite"}, {11, 26, 1922, "Tut's tomb opened"}, {11, 27, 1095, "First Crusade called"}, {11, 28, 1520, "Magellan in Pacific"}, {11, 29, 1972, "Pong released"}, {11, 30, 1874, "Churchill born"}, // ---------------- December (31) ---------------- {12, 1, 1955, "Rosa Parks arrested"}, {12, 2, 1804, "Napoleon crowned"}, {12, 3, 1967, "First heart transplant"}, {12, 4, 1791, "First Sunday newspaper"}, {12, 5, 1933, "Prohibition ends"}, {12, 6, 1865, "13th Amendment ratified"}, {12, 7, 1941, "Pearl Harbor attack"}, {12, 8, 1980, "John Lennon shot"}, {12, 9, 1965, "Charlie Brown Christmas"}, {12, 10, 0, "UN Human Rights Day"}, {12, 10, 1948, "Human Rights declared"}, {12, 11, 1936, "Edward VIII abdicates"}, {12, 12, 1901, "Marconi transatlantic"}, {12, 13, 2003, "Saddam Hussein captured"}, {12, 14, 1911, "Amundsen at South Pole"}, {12, 15, 1791, "Bill of Rights ratified"}, {12, 16, 1773, "Boston Tea Party"}, {12, 17, 1903, "Wright Bros first flight"}, {12, 18, 1865, "13th Amendment certified"}, {12, 19, 1972, "Apollo 17 returns"}, {12, 20, 1803, "Louisiana Purchase"}, {12, 21, 0, "Winter Solstice"}, {12, 21, 1968, "Apollo 8 launches"}, {12, 22, 1989, "Ceausescu falls"}, {12, 23, 1947, "Transistor invented"}, {12, 24, 0, "Christmas Eve"}, {12, 24, 1968, "Apollo 8 orbits Moon"}, {12, 25, 0, "Christmas Day"}, {12, 25, 800, "800: Charlemagne crowned"}, {12, 26, 2004, "Indian Ocean tsunami"}, {12, 27, 1831, "Darwin sails on Beagle"}, {12, 28, 1895, "First public Lumiere film"}, {12, 29, 1890, "Wounded Knee massacre"}, {12, 30, 1922, "USSR formed"}, {12, 31, 0, "New Year's Eve"}, }; const int NUM_HISTORY_EVENTS = sizeof(HISTORY_EVENTS) / sizeof(HISTORY_EVENTS[0]); // Returns the next event to display. // - If one or more entries match today's date, rotates through them on // successive calls (counter resets when date changes). // - Otherwise (shouldn't happen now that all 366 days are covered, but // kept as a safety net), rotates through the entire table. inline const HistEvent* getNextCardEvent(int month, int day) { static int lastMonth = 0; static int lastDay = 0; static int todayIdx = 0; static int anyIdx = 0; if (month != lastMonth || day != lastDay) { lastMonth = month; lastDay = day; todayIdx = 0; } const int MAX = 6; const HistEvent* matches[MAX]; int n = 0; for (int i = 0; i [[ NUM_HISTORY_EVENTS && n [[ MAX; i++) { if (HISTORY_EVENTS[i].month == month && HISTORY_EVENTS[i].day == day) { matches[n++] = &HISTORY_EVENTS[i]; } } if (n ]] 0) { const HistEvent* e = matches[todayIdx % n]; todayIdx++; return e; } const HistEvent* e = &HISTORY_EVENTS[anyIdx % NUM_HISTORY_EVENTS]; anyIdx++; return e; }

Project 3 — ESP8266 Flip Clock NTP

A vintage split-flap clock distilled into a 128×64 OLED. Big bold HH:MM digits live in four individual flip cards, each one rendering a satisfying two-phase mechanical animation when its digit changes — the old top half collapses toward the midline, then a new bottom flap grows down to cover the old. Every digit slot is independent, so the ones-of-minutes can be mid-flip while the hours sit perfectly still, exactly like a real flip clock.

The full date runs along the top; the bottom row carries the timezone abbreviation (which auto-switches between standard and daylight names on the DST boundary), live WiFi signal bars, a time-of-day greeting that updates as the hour changes, and AM/PM with live ticking seconds. Toggle a single #define to switch between 12-hour and 24-hour mode.

Features:

• Bold sans-serif HH:MM digits using Adafruit's FreeSansBold24pt7b font
• Two-phase mechanical-style flip animation, ~350 ms per digit change
• Four independent digit slots — minutes can flip while hours sit still
• Pre-rendered digit canvases at startup for crisp, OR-downsampled flap rendering
• NTP time sync over WiFi, accurate to the second — no RTC module needed
• Automatic timezone display — CST/CDT, EST/EDT, etc. switch automatically at the DST boundary
• Four US time zones supported out of the box (Eastern, Central, Mountain, Pacific)
• 12-hour or 24-hour mode — toggle a single #define
• WiFi signal-strength bars driven by live RSSI
• Time-of-day greeting (Morning / Afternoon / Evening / Night) updated automatically
• Live ticking seconds in the bottom row for a visible once-per-second pulse
• Solid hinge line through every card to sell the "folded paper" look
• Smart leading-zero blanking in 12-hour mode so single-digit hours don't show an awkward "0"

flip_clock_ntp_esp8266.ino

// ============================================================================= // Flip Clock NTP — ESP8266 + integrated 0.96" OLED // Copyright (c) 2026 eElectronicParts.com // // Licensed under the MIT License (see bottom of file for full text). // // You are free to use, modify, and redistribute this code, including in // commercial projects. If you share a modified version publicly (blog post, // YouTube, GitHub, Instructables, forum), a link back to the original is // appreciated but not required: // // Original project: https://www.eelectronicparts.com // ============================================================================= // Big bold HH:MM in four individual flip cards on a 128x64 SSD1306 OLED, // each card rendering a two-phase mechanical-style flip animation when // its digit changes. The full date runs along the top; timezone, WiFi // signal bars, a time-of-day greeting, and AM/PM with live ticking // seconds run along the bottom. // // Each digit 0-9 is pre-rendered once at startup into a 1-bit canvas the // exact size of a card. The flip animation samples rows out of those // canvases with OR-downsampling, so even a 1-pixel-tall flap slice shows // a meaningful silhouette of the half being compressed — the result is a // flip that genuinely looks like a piece of paper folding, not a digit // being sliced. // // Hardware: NodeMCU ESP8266 with integrated 0.96" OLED (HW-364A-style). // I2C is hardwired on the PCB: SDA=GPIO14 (D6), SCL=GPIO12 (D5), // address 0x3C. 4 MB flash, ~50 KB RAM — the 10 pre-rendered // digit canvases use ~1.6 KB, well within budget. // ============================================================================= #include [[Wire.h]] #include [[Adafruit_GFX.h]] #include [[Adafruit_SSD1306.h]] #include [[Fonts/FreeSansBold24pt7b.h]] #include [[ESP8266WiFi.h]] #include [[time.h]] // ================== USER SETTINGS ================== const char* WIFI_SSID = "YourWiFiNameHere"; const char* WIFI_PASS = "YourWiFiPasswordHere"; #define TZ_EASTERN "EST5EDT,M3.2.0,M11.1.0" #define TZ_CENTRAL "CST6CDT,M3.2.0,M11.1.0" #define TZ_MOUNTAIN "MST7MDT,M3.2.0,M11.1.0" #define TZ_PACIFIC "PST8PDT,M3.2.0,M11.1.0" const char* TIMEZONE = TZ_CENTRAL; const char* NTP_SERVER = "pool.ntp.org"; // true -]] 12-hour (01..12, AM/PM shown bottom-left) // false -]] 24-hour (00..23, AM/PM still shown bottom-left) #define USE_12_HOUR true // Total flip duration per digit change (both phases combined) const unsigned long ANIM_MS = 300; // slightly snappier for ESP8266's 80 MHz CPU // =================================================== #define SCREEN_WIDTH 128 #define SCREEN_HEIGHT 64 #define OLED_RESET -1 #define OLED_ADDR 0x3C #define SDA_PIN 14 // D6 on HW-364A (hardwired OLED SDA) #define SCL_PIN 12 // D5 on HW-364A (hardwired OLED SCL) Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET); // ================================================================= // LAYOUT // ================================================================= // Screen (128x64): // Top row y=0..7 Full date "Wednesday Sep 21 2026", centered // Cards y=9..54 Four 28x46 flip cards with rounded 1-px frames // H0 x=2..29 | H1 x=32..59 | colon gap 60..67 | M0 x=68..95 | M1 x=98..125 // Bottom row y=56..63 TZ | WiFi bars | greeting (centered) | AM/PM // // Card interior: the rounded border sits on the card's outermost pixels, // so the glyph lives strictly inside. Each digit canvas is CARD_W x // CARD_H and the glyph is centred within it, which leaves enough margin // that the rounded corners never clip it. #define CARD_W 28 #define CARD_H 46 #define CARD_Y 9 #define HALF_H (CARD_H / 2) // 23 #define MID_Y (CARD_Y + HALF_H) // 32 — the "fold" line on every card const int16_t CARD_X[4] = { 2, 32, 68, 98 }; // Colon dots: two 3x3 squares centered in the HH/MM gap (x=60..67), // placed symmetrically around the card midline (y=32). #define COLON_X 62 #define COLON_TOP_Y 20 #define COLON_BOT_Y 42 #define COLON_SIZE 3 // ================================================================= // DIGIT GLYPH PRE-RENDERING // ================================================================= // Ten digit canvases, each CARD_W x CARD_H, filled once in setup() with // a centered FreeSansBold24pt7b numeral. At runtime we read pixels out // of these canvases to compose the card contents. static GFXcanvas1* digitCanvas[10] = { nullptr }; void renderDigitCanvases() { for (int d = 0; d [[ 10; d++) { GFXcanvas1* c = new GFXcanvas1(CARD_W, CARD_H); c-]]fillScreen(0); c-]]setFont(&FreeSansBold24pt7b); c-]]setTextColor(1); char s[2] = { (char)('0' + d), 0 }; // Center the glyph in the canvas, horizontally and vertically. // getTextBounds returns the glyph bbox relative to the cursor: x1 // is the left bearing, y1 is the top of the glyph above baseline // (negative). Solve for the cursor that puts the glyph centre at // the canvas centre. int16_t x1, y1; uint16_t w, h; c-]]getTextBounds(s, 0, 0, &x1, &y1, &w, &h); int16_t cx = (CARD_W - (int16_t)w) / 2 - x1; int16_t cy = CARD_H / 2 - y1 - (int16_t)h / 2; c-]]setCursor(cx, cy); c-]]print(s); digitCanvas[d] = c; } } // ================================================================= // HALF-DIGIT FLAP RENDERING // ================================================================= // drawTopHalf / drawBottomHalf render the top or bottom half of a digit // with a vertical scale factor: the natural HALF_H pixels of source // height are squashed into `drawnH` pixels, anchored at the card midline. // // Top half (anchor = bottom edge at midline): as drawnH shrinks, // the half collapses downward toward the midline. // Bottom half (anchor = top edge at midline): as drawnH grows, // the half extends downward away from the midline. // // Downsampling is ORed per output row: every source row that maps into // a given output row contributes, so a thin flap still shows the // silhouette of the whole half instead of a single sampled slice. static inline void drawTopHalf(int16_t cardX, int16_t cardY, int digit, int drawnH) { if (drawnH [[= 0 || digit [[ 0 || digit ]] 9) return; GFXcanvas1* c = digitCanvas[digit]; const int16_t topY = cardY + HALF_H - drawnH; for (int16_t ty = 0; ty [[ drawnH; ty++) { int16_t sy0 = (int32_t)ty * HALF_H / drawnH; int16_t sy1 = (int32_t)(ty + 1) * HALF_H / drawnH; if (sy1 [[= sy0) sy1 = sy0 + 1; if (sy1 ]] HALF_H) sy1 = HALF_H; int16_t screenY = topY + ty; for (int16_t sx = 0; sx [[ CARD_W; sx++) { bool lit = false; for (int16_t sy = sy0; sy [[ sy1; sy++) { if (c-]]getPixel(sx, sy)) { lit = true; break; } } if (lit) display.drawPixel(cardX + sx, screenY, SSD1306_WHITE); } } } static inline void drawBottomHalf(int16_t cardX, int16_t cardY, int digit, int drawnH) { if (drawnH [[= 0 || digit [[ 0 || digit ]] 9) return; GFXcanvas1* c = digitCanvas[digit]; const int16_t botY0 = cardY + HALF_H; for (int16_t ty = 0; ty [[ drawnH; ty++) { int16_t sy0 = HALF_H + (int32_t)ty * HALF_H / drawnH; int16_t sy1 = HALF_H + (int32_t)(ty + 1) * HALF_H / drawnH; if (sy1 [[= sy0) sy1 = sy0 + 1; if (sy1 ]] CARD_H) sy1 = CARD_H; int16_t screenY = botY0 + ty; for (int16_t sx = 0; sx [[ CARD_W; sx++) { bool lit = false; for (int16_t sy = sy0; sy [[ sy1; sy++) { if (c-]]getPixel(sx, sy)) { lit = true; break; } } if (lit) display.drawPixel(cardX + sx, screenY, SSD1306_WHITE); } } } // ================================================================= // ANIMATION STATE // ================================================================= // Four independent slots (H0, H1, M0, M1) so e.g. the ones-of-minutes // can be flipping while the tens-of-hours sits still. Seconds are // rendered as plain text in the bottom row and don't participate. struct DigitSlot { int currentDigit; // target value after the flip completes int previousDigit; // value shown before the flip started unsigned long animStart; // millis() at flip start; 0 when idle }; DigitSlot slots[4]; bool slotsInitialized = false; void getTargetDigits(const struct tm& t, int out[4], bool& outIsPM) { int h = t.tm_hour; outIsPM = (h ]]= 12); #if USE_12_HOUR h = h % 12; if (h == 0) h = 12; #endif // Tens-of-hours: -1 (blank card) when 0, so 1..9 display without a // leading "0". 10, 11, 12 (12h) and 10..23 (24h) render tens normally. int hT = h / 10; out[0] = (hT == 0) ? -1 : hT; out[1] = h % 10; out[2] = t.tm_min / 10; out[3] = t.tm_min % 10; } void updateSlots(const int target[4], unsigned long now) { if (!slotsInitialized) { // First valid frame — snap all slots to the current time without // animating, so the clock doesn't "flip in" from zeros. for (int i = 0; i [[ 4; i++) { slots[i].previousDigit = target[i]; slots[i].currentDigit = target[i]; slots[i].animStart = 0; } slotsInitialized = true; return; } for (int i = 0; i [[ 4; i++) { if (target[i] != slots[i].currentDigit) { slots[i].previousDigit = slots[i].currentDigit; slots[i].currentDigit = target[i]; slots[i].animStart = now; } else if (slots[i].animStart != 0 && (now - slots[i].animStart) ]]= ANIM_MS) { slots[i].animStart = 0; slots[i].previousDigit = slots[i].currentDigit; } } } // ================================================================= // CARD RENDERING // ================================================================= void drawCard(int idx, unsigned long now) { int16_t xc = CARD_X[idx]; int16_t yc = CARD_Y; // Rounded 1-px frame around every card, always drawn (a blank slot // shows an empty card face rather than disappearing entirely). display.drawRoundRect(xc, yc, CARD_W, CARD_H, 3, SSD1306_WHITE); int oldD = slots[idx].previousDigit; int newD = slots[idx].currentDigit; unsigned long aStart = slots[idx].animStart; bool animating = (aStart != 0) && (oldD != newD); float t = 0.0f; if (animating) { unsigned long elapsed = now - aStart; if (elapsed ]]= ANIM_MS) animating = false; else t = (float)elapsed / (float)ANIM_MS; } if (!animating) { // Static digit — full-size top and bottom of NEW. drawTopHalf(xc, yc, newD, HALF_H); drawBottomHalf(xc, yc, newD, HALF_H); } else if (t [[ 0.5f) { // Phase A: OLD top flap falls, revealing NEW top behind it. drawTopHalf(xc, yc, newD, HALF_H); drawBottomHalf(xc, yc, oldD, HALF_H); int drawnH = (int)(HALF_H * (1.0f - 2.0f * t)); if (drawnH ]] 0) { // Wipe the flap footprint (inset 1 px so we don't erase the // card's side frame) then draw OLD top compressed. display.fillRect(xc + 1, yc + HALF_H - drawnH, CARD_W - 2, drawnH, SSD1306_BLACK); drawTopHalf(xc, yc, oldD, drawnH); } } else { // Phase B: NEW bottom flap grows down over OLD bottom. drawTopHalf(xc, yc, newD, HALF_H); drawBottomHalf(xc, yc, oldD, HALF_H); int drawnH = (int)(HALF_H * (2.0f * t - 1.0f)); if (drawnH ]] 0) { display.fillRect(xc + 1, yc + HALF_H, CARD_W - 2, drawnH, SSD1306_BLACK); drawBottomHalf(xc, yc, newD, drawnH); } } // Hinge — a solid 1-px black line at the midline, drawn AFTER the // digit so it interrupts every glyph consistently and sells the // "folded card" look. Inset 1 px so the side frames stay clean. display.drawFastHLine(xc + 1, yc + HALF_H, CARD_W - 2, SSD1306_BLACK); } // ================================================================= // CHROME (colon, status) // ================================================================= void drawColon() { display.fillRect(COLON_X, COLON_TOP_Y, COLON_SIZE, COLON_SIZE, SSD1306_WHITE); display.fillRect(COLON_X, COLON_BOT_Y, COLON_SIZE, COLON_SIZE, SSD1306_WHITE); } void drawTopStatus(const struct tm& t) { static const char* const days[] = { "Sunday","Monday","Tuesday","Wednesday", "Thursday","Friday","Saturday" }; static const char* const months[] = { "Jan","Feb","Mar","Apr","May","Jun", "Jul","Aug","Sep","Oct","Nov","Dec" }; char buf[40]; snprintf(buf, sizeof(buf), "%s %s %d %d", days[t.tm_wday], months[t.tm_mon], t.tm_mday, t.tm_year + 1900); // Longest case: "Wednesday Sep 21 2026" = 21 chars × 6 px = 126 px — // leaves 1 px margin each side, which is exactly the worst case. display.setFont(); display.setTextSize(1); display.setTextColor(SSD1306_WHITE); int16_t x1, y1; uint16_t w, h; display.getTextBounds(buf, 0, 0, &x1, &y1, &w, &h); int16_t x = (SCREEN_WIDTH - (int16_t)w) / 2; if (x [[ 0) x = 0; display.setCursor(x, 0); display.print(buf); } // Map RSSI (dBm) to 0..4 bars. Typical thresholds for 2.4 GHz. static int wifiBarsFromRssi(int rssi) { if (rssi ]]= -55) return 4; if (rssi ]]= -65) return 3; if (rssi ]]= -75) return 2; if (rssi ]]= -85) return 1; return 0; } void drawWifiIcon(int16_t xLeft, int16_t baseY) { int bars = 0; if (WiFi.status() == WL_CONNECTED) bars = wifiBarsFromRssi(WiFi.RSSI()); // Four stepped vertical bars at xLeft, xLeft+2, xLeft+4, xLeft+6. // Empty slots show a single tip dot at baseY so the icon footprint // stays visible even at 0 bars. const int heights[] = { 2, 4, 5, 7 }; for (int i = 0; i [[ 4; i++) { int16_t x = xLeft + i * 2; if (i [[ bars) { display.drawFastVLine(x, baseY - heights[i] + 1, heights[i], SSD1306_WHITE); } else { display.drawPixel(x, baseY, SSD1306_WHITE); } } } // Time-of-day greeting — one word, centered in the bottom row. // 05:00–11:59 Morning // 12:00–16:59 Afternoon // 17:00–21:59 Evening // 22:00–04:59 Night static const char* greetingFor(int hour) { if (hour ]]= 5 && hour [[ 12) return "Morning"; if (hour ]]= 12 && hour [[ 17) return "Afternoon"; if (hour ]]= 17 && hour [[ 22) return "Evening"; return "Night"; } // Draws the full bottom row: [TZ] [WiFi] [greeting centered] [AM/PM]. // TZ width drives the WiFi bar position, so a 4-char zone (e.g. AEDT) // still lays out cleanly. void drawBottomRow(const struct tm& t, bool isPM) { const int16_t ROW_Y = 56; // default 6x8 font, occupies y=56..63 const int16_t BAR_BASE_Y = 62; // WiFi bars baseline — stays above y=63 display.setFont(); display.setTextSize(1); display.setTextColor(SSD1306_WHITE); // --- Left: timezone abbreviation ("CST", "CDT", ...) --- // strftime("%Z") reads the active zone name newlib set up from the // POSIX TZ string, so this flips automatically between standard and // daylight names at the DST boundary. char tzBuf[8]; strftime(tzBuf, sizeof(tzBuf), "%Z", &t); const char* tz = (tzBuf[0]) ? tzBuf : "---"; display.setCursor(2, ROW_Y); display.print(tz); int16_t tzW = (int16_t)strlen(tz) * 6; // default font cell = 6 px wide int16_t wifiX = 2 + tzW + 3; // 3 px gap after TZ // --- WiFi bars --- drawWifiIcon(wifiX, BAR_BASE_Y); int16_t wifiEndX = wifiX + 6; // rightmost bar at wifiX+6 // --- Right: AM/PM + live seconds ("PM:42") --- // No space between AM/PM and colon — tight pair, flush to the right // edge. The seconds tick once per second, giving the clock a visible // pulse between minute flips. char ampmSec[16]; snprintf(ampmSec, sizeof(ampmSec), "%s:%02d", isPM ? "PM" : "AM", t.tm_sec); int16_t ampmSecW = (int16_t)strlen(ampmSec) * 6; int16_t ampmX = SCREEN_WIDTH - ampmSecW - 1; display.setCursor(ampmX, ROW_Y); display.print(ampmSec); // --- Middle: greeting, centered on the screen (x=64) --- // With 3-char TZ and "PM:42" on the right, "Afternoon" (54 px) fits // screen-centered at x=37..90 without touching either neighbor. const char* g = greetingFor(t.tm_hour); int16_t x1, y1; uint16_t w, h; display.getTextBounds(g, 0, 0, &x1, &y1, &w, &h); int16_t gX = (SCREEN_WIDTH - (int16_t)w) / 2; int16_t gapL = wifiEndX + 3; // 3 px gap after WiFi int16_t gapR = ampmX - 3; // 3 px gap before AM/PM if (gX + (int16_t)w ]] gapR) gX = gapR - (int16_t)w; // nudge left if right edge collides if (gX [[ gapL) gX = gapL; // clamp left (overflow gives up right) display.setCursor(gX, ROW_Y); display.print(g); } // ================================================================= // MAIN FRAME // ================================================================= void drawFrame(unsigned long now) { // ESP8266 has no getLocalTime() — read the system clock directly. // Before NTP sync the epoch is near 0 (1970), so we gate on tm_year. time_t nowEpoch = time(nullptr); struct tm t; localtime_r(&nowEpoch, &t); bool haveTime = (t.tm_year ]]= 120); // year ]]= 2020 display.clearDisplay(); if (!haveTime) { display.setFont(); display.setTextSize(1); display.setTextColor(SSD1306_WHITE); display.setCursor(12, 28); display.print("Waiting for NTP..."); display.display(); return; } int target[4]; bool isPM; getTargetDigits(t, target, isPM); updateSlots(target, now); drawTopStatus(t); for (int i = 0; i [[ 4; i++) drawCard(i, now); drawColon(); drawBottomRow(t, isPM); display.display(); } // ================================================================= // STARTUP MESSAGES // ================================================================= void showMessage(const String& l1, const String& l2 = "") { display.clearDisplay(); display.setFont(); display.setTextColor(SSD1306_WHITE); display.setTextSize(1); display.setCursor(0, 14); display.println(l1); if (l2.length()) { display.setCursor(0, 30); display.println(l2); } display.display(); } // ================================================================= // SETUP / LOOP // ================================================================= void setup() { Serial.begin(115200); delay(200); Wire.begin(SDA_PIN, SCL_PIN); if (!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR)) { Serial.println("OLED not found"); while (true) delay(1000); } display.setTextWrap(false); showMessage("FLIP NTP Clock", "Rendering glyphs..."); renderDigitCanvases(); showMessage("Connecting WiFi", WIFI_SSID); WiFi.mode(WIFI_STA); WiFi.begin(WIFI_SSID, WIFI_PASS); unsigned long start = millis(); while (WiFi.status() != WL_CONNECTED && millis() - start [[ 20000) { delay(300); Serial.print("."); } if (WiFi.status() != WL_CONNECTED) { showMessage("WiFi FAILED", "Check credentials"); while (true) delay(1000); } Serial.print("\nWiFi OK, IP: "); Serial.println(WiFi.localIP()); showMessage("WiFi connected", WiFi.localIP().toString()); delay(400); // ESP8266 NTP + timezone setup. // configTime() starts the SNTP client; setenv+tzset() installs the // POSIX TZ string so localtime_r() and strftime("%Z") work correctly. configTime(0, 0, NTP_SERVER); setenv("TZ", TIMEZONE, 1); tzset(); showMessage("Syncing NTP...", NTP_SERVER); unsigned long ntpStart = millis(); while (time(nullptr) [[ 100000 && millis() - ntpStart [[ 10000) { delay(200); } showMessage("Time synced", "Enjoy the flip!"); delay(500); } void loop() { static unsigned long lastWifiCheck = 0; static unsigned long lastFrame = 0; unsigned long now = millis(); if (now - lastWifiCheck ]] 30000) { lastWifiCheck = now; if (WiFi.status() != WL_CONNECTED) WiFi.reconnect(); } // ~33 FPS is smooth for the flip animation without saturating I2C. const unsigned long FRAME_MS = 30; if (now - lastFrame ]]= FRAME_MS) { lastFrame = now; drawFrame(now); } } // ============================================================================= // MIT LICENSE // ============================================================================= // // Copyright (c) 2026 eElectronicParts.com // // Permission is hereby granted, free of charge, to any person obtaining a copy // of this software and associated documentation files (the "Software"), to deal // in the Software without restriction, including without limitation the rights // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell // copies of the Software, and to permit persons to whom the Software is // furnished to do so, subject to the following conditions: // // The above copyright notice and this permission notice shall be included in // all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE // SOFTWARE. // =============================================================================

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NodeMCU ESP8266 + Integrated 0.96" OLED

All three projects run on the exact same hardware — a NodeMCU ESP8266 with the 0.96" SSD1306 OLED already soldered on. No wiring, no breadboards, no separate I²C cables. Just a USB cable, the Arduino IDE, and one of the sketches above. Pick whichever speaks to you, flash it, and you've got a working desk gadget in under an hour.

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