#include <Arduino.h>

// --- Pin definition ---
#define LED1 D3
#define LED2 D5

void setup() {
  Serial.begin(115200);

  pinMode(LED1, OUTPUT);
  pinMode(LED2, OUTPUT);

  digitalWrite(LED1, LOW);
  digitalWrite(LED2, LOW);

  Serial.println("Ready to receive commands...");
}

void loop() {
  if (Serial.available()) {
    char cmd = Serial.read();

    switch (cmd) {
      case 'A':
        digitalWrite(LED1, HIGH);
        Serial.println("LED D3 ON");
        break;

      case 'B':
        digitalWrite(LED1, LOW);
        Serial.println("LED D3 OFF");
        break;

      case 'C':
        digitalWrite(LED2, HIGH);
        Serial.println("LED D5 ON");
        break;

      case 'D':
        digitalWrite(LED2, LOW);
        Serial.println("LED D5 OFF");
        break;
    }
  }
}