#define LEDPIN 8

String incomingString;

void setup() {
  pinMode(LEDPIN, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  if (Serial.available() > 0) {
    char cmd = Serial.read();
    if (cmd == 'O') {
      digitalWrite(LEDPIN, HIGH);  // Open
    } else if (cmd == 'C') {
      digitalWrite(LEDPIN, LOW);   // Close
    } else if (cmd == 'R') {
      int ldrValue = analogRead(A0);
      Serial.println(ldrValue);
    }
  }
  delay(50);
}