Animated IoT Keychain Face

#include <Arduino.h>
#include <Wire.h>
#include <WiFi.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>


// Forward declarations
void drawEye(int centerX, bool closed);
void drawMouth(bool online);
void drawStatus(bool online);
void connectWiFi();

constexpr int OLED_SDA_PIN = 21;
constexpr int OLED_SCL_PIN = 22;
constexpr uint8_t OLED_ADDRESS = 0x3C;
constexpr int SCREEN_WIDTH = 128;
constexpr int SCREEN_HEIGHT = 64;
constexpr unsigned long FRAME_INTERVAL_MS = 50;
constexpr unsigned long BLINK_INTERVAL_MS = 3500;
constexpr unsigned long BLINK_LENGTH_MS = 180;
constexpr unsigned long WINK_INTERVAL_MS = 11500;
constexpr unsigned long WINK_LENGTH_MS = 420;

// Enter the Wi-Fi network the keychain should join.
const char *WIFI_SSID = "YOUR_WIFI_NAME";
const char *WIFI_PASSWORD = "YOUR_WIFI_PASSWORD";

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

unsigned long lastFrameMs = 0;
unsigned long lastBlinkStartMs = 0;
unsigned long lastWinkStartMs = 0;
bool previousLeftClosed = false;
bool previousRightClosed = false;
bool previousOnline = false;
bool initialDraw = true;

void drawEye(int centerX, bool closed) {
  const int eyeTop = 16;
  const int eyeWidth = 30;
  const int eyeHeight = 24;
  display.fillRect(centerX - (eyeWidth / 2) - 2, eyeTop - 2, eyeWidth + 4, eyeHeight + 7, SSD1306_BLACK);

  if (closed) {
    display.drawLine(centerX - 13, 37, centerX + 13, 37, SSD1306_WHITE);
    display.drawLine(centerX - 11, 38, centerX + 11, 38, SSD1306_WHITE);
  } else {
    display.fillRoundRect(centerX - 15, eyeTop, eyeWidth, eyeHeight, 10, SSD1306_WHITE);
    display.fillRoundRect(centerX - 5, eyeTop + 5, 10, 15, 5, SSD1306_BLACK);
  }
}

void drawMouth(bool online) {
  display.fillRect(30, 46, 68, 15, SSD1306_BLACK);
  if (online) {
    display.drawLine(43, 51, 48, 55, SSD1306_WHITE);
    display.drawLine(48, 55, 64, 57, SSD1306_WHITE);
    display.drawLine(64, 57, 80, 55, SSD1306_WHITE);
    display.drawLine(80, 55, 85, 51, SSD1306_WHITE);
  } else {
    display.drawLine(43, 56, 85, 56, SSD1306_WHITE);
  }
}

void drawStatus(bool online) {
  display.fillRect(0, 0, SCREEN_WIDTH, 10, SSD1306_BLACK);
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(2, 1);
  display.print(online ? "WiFi :)" : "WiFi ...");
}

void connectWiFi() {
  if (strcmp(WIFI_SSID, "YOUR_WIFI_NAME") == 0) {
    return;
  }
  WiFi.mode(WIFI_STA);
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
}

void setup() {
  Wire.begin(OLED_SDA_PIN, OLED_SCL_PIN);
  if (!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDRESS)) {
    while (true) {
      delay(1000);
    }
  }
  display.clearDisplay();
  display.display();
  connectWiFi();
}

void loop() {
  const unsigned long now = millis();
  const bool online = WiFi.status() == WL_CONNECTED;

  if (now - lastBlinkStartMs >= BLINK_INTERVAL_MS) {
    lastBlinkStartMs = now;
  }
  if (now - lastWinkStartMs >= WINK_INTERVAL_MS) {
    lastWinkStartMs = now;
  }

  const bool blinking = (now - lastBlinkStartMs) < BLINK_LENGTH_MS;
  const bool winking = (now - lastWinkStartMs) < WINK_LENGTH_MS;
  const bool leftClosed = blinking || winking;
  const bool rightClosed = blinking;

  if (initialDraw || now - lastFrameMs >= FRAME_INTERVAL_MS) {
    if (initialDraw) {
      display.clearDisplay();
    }
    if (initialDraw || leftClosed != previousLeftClosed) {
      drawEye(38, leftClosed);
    }
    if (initialDraw || rightClosed != previousRightClosed) {
      drawEye(90, rightClosed);
    }
    if (initialDraw || online != previousOnline) {
      drawMouth(online);
      drawStatus(online);
    }
    if (initialDraw || leftClosed != previousLeftClosed || rightClosed != previousRightClosed || online != previousOnline) {
      display.display();
      previousLeftClosed = leftClosed;
      previousRightClosed = rightClosed;
      previousOnline = online;
      initialDraw = false;
    }
    lastFrameMs = now;
  }

  if (!online && strcmp(WIFI_SSID, "YOUR_WIFI_NAME") != 0 && WiFi.status() == WL_CONNECT_FAILED) {
    WiFi.disconnect();
    WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
  }
}