Wemos ESP8266 D1 Mini led beacon example

esp8266-led-swell.ino

// Wemos Mini D1 Pro pinout. This should have been provided by selecting the correct board but this
// board wasn't available when I looked for it so whatever this requires less dependency on the
// Arduino IDE configuration anyway.
// https://arduino-projekte.info/wp-content/uploads/2017/03/wemos_d1_mini_pro_pinout.png
byte PIN_D0 = 16;
byte PIN_D1 = 5;
byte PIN_D2 = 4;
byte PIN_D3 = 0;
byte PIN_D4 = 2;
byte PIN_D5 = 14;
byte PIN_D6 = 12;
byte PIN_D7 = 13;
byte PIN_D8 = 15;

void setup() {
  Serial.begin(115200);
}
void loop() {
  // Increase the LED brightness using PWM
  for(int dutyCycle = 0; dutyCycle < 1023; dutyCycle++){   
    analogWrite(PIN_D3, dutyCycle);
    delay(1);
  }

  // Decrease the LED brightness using PWM
  for(int dutyCycle = 1023; dutyCycle > 0; dutyCycle--){
    analogWrite(PIN_D3, dutyCycle);
    delay(1);
  }
}