/*
  Input   : LDR Module
  Output  : 3 LEDs (Red, Yellow, Green)
  Project : Light up LEDs according to Surrounding Condition
  Edited  : 5th Feb 2026 by Zarina MN
*/

#define RED_LED 5
#define YELLOW_LED 6
#define GREEN_LED 7
#define LDR_PIN A3

void setup() {
  Serial.begin(9600);           // Sets the serial port to 9600 baud rate
  pinMode(RED_LED, OUTPUT);
  pinMode(YELLOW_LED, OUTPUT);
  pinMode(GREEN_LED, OUTPUT);
}

void loop() {
  int ldr_read = analogRead(LDR_PIN);
	Serial.print("LDR reading: ");
  Serial.print(ldr_read);
  delay(2000);                  // Delay for 2s

  if (ldr_read <= 1024/3) {
    digitalWrite(RED_LED, HIGH);
    digitalWrite(YELLOW_LED, LOW);
    digitalWrite(GREEN_LED, LOW);
    Serial.println(" >> Too bright! RED LED ON");
  }
  else if (ldr_read > 1024/3 && ldr_read <= 1024/3*2){
    digitalWrite(RED_LED, LOW);
    digitalWrite(YELLOW_LED, HIGH);
    digitalWrite(GREEN_LED, LOW);
    Serial.println(" >> Moderate lighting! YELLOW LED ON");
  }
  else {
    digitalWrite(RED_LED, LOW);
    digitalWrite(YELLOW_LED, LOW);
    digitalWrite(GREEN_LED, HIGH);
    Serial.println(" >> Almost dark! GREEN LED ON");
  }
}