Documentation

// Blink the onboard TX/RX LEDs since the Pro Micro has no
// dedicated user LED on a GPIO pin. D13 is not an LED here.

void setup() {
  // Both built-in LEDs are available:
  // LED_BUILTIN_TX (PD5) and LED_BUILTIN_RX (PB0)
  pinMode(LED_BUILTIN_TX, OUTPUT);
  pinMode(LED_BUILTIN_RX, OUTPUT);
}

void loop() {
  digitalWrite(LED_BUILTIN_TX, LOW);   // LEDs are active-LOW
  digitalWrite(LED_BUILTIN_RX, HIGH);
  delay(500);
  digitalWrite(LED_BUILTIN_TX, HIGH);
  digitalWrite(LED_BUILTIN_RX, LOW);
  delay(500);
}

// Wire a pushbutton between D2 and GND.
// When pressed, the Pro Micro types "Hello from Pro Micro!"
// as if it were a real USB keyboard.

#include <Keyboard.h>

const int BUTTON_PIN = 2;
bool lastState = HIGH;

void setup() {
  pinMode(BUTTON_PIN, INPUT_PULLUP);
  Keyboard.begin();
}

void loop() {
  bool state = digitalRead(BUTTON_PIN);

  // Trigger on press (HIGH -> LOW transition)
  if (lastState == HIGH && state == LOW) {
    Keyboard.print("Hello from Pro Micro!");
    Keyboard.press(KEY_RETURN);
    Keyboard.releaseAll();
    delay(50);  // debounce
  }

  lastState = state;
}

// Classic "mouse jiggler" — moves the cursor a pixel every
// 30 seconds so your computer thinks you're still at it.

#include <Mouse.h>

void setup() {
  Mouse.begin();
}

void loop() {
  Mouse.move(1, 0, 0);
  delay(100);
  Mouse.move(-1, 0, 0);
  delay(30000);  // 30 seconds
}

// Scans the I2C bus and prints the address of every device
// it finds. Useful first sketch to verify SDA/SCL wiring.

#include <Wire.h>

void setup() {
  Wire.begin();
  Serial.begin(9600);
  while (!Serial) { ; }  // Wait for native USB CDC port
  Serial.println("I2C Scanner");
}

void loop() {
  byte found = 0;

  for (byte addr = 1; addr < 127; addr++) {
    Wire.beginTransmission(addr);
    if (Wire.endTransmission() == 0) {
      Serial.print("Device at 0x");
      if (addr < 16) Serial.print("0");
      Serial.println(addr, HEX);
      found++;
    }
  }

  if (found == 0) Serial.println("No devices found");
  delay(5000);
}

// Turns the Pro Micro into a media control remote.
// Requires the HID-Project library (install via Library Manager).
// Wire three buttons: D2=Play/Pause, D3=Next, D4=Previous.

#include <HID-Project.h>

const int PLAY_PIN = 2;
const int NEXT_PIN = 3;
const int PREV_PIN = 4;

void setup() {
  pinMode(PLAY_PIN, INPUT_PULLUP);
  pinMode(NEXT_PIN, INPUT_PULLUP);
  pinMode(PREV_PIN, INPUT_PULLUP);
  Consumer.begin();
}

void loop() {
  if (digitalRead(PLAY_PIN) == LOW) {
    Consumer.write(MEDIA_PLAY_PAUSE);
    delay(200);
  }
  if (digitalRead(NEXT_PIN) == LOW) {
    Consumer.write(MEDIA_NEXT);
    delay(200);
  }
  if (digitalRead(PREV_PIN) == LOW) {
    Consumer.write(MEDIA_PREVIOUS);
    delay(200);
  }
}