---

const int redLedPin = 2;
const int greenLedPin = 3;
const int yellowLedPin = 4;
const int ldrPin = A0;

const int darkThreshold = 300;
const int brightThreshold = 700;

void setup() {
  pinMode(redLedPin, OUTPUT);
  pinMode(greenLedPin, OUTPUT);
  pinMode(yellowLedPin, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  int lightLevel = analogRead(ldrPin);
  
  if (lightLevel < darkThreshold) {
    digitalWrite(redLedPin, HIGH);
    digitalWrite(greenLedPin, LOW);
    digitalWrite(yellowLedPin, LOW);
  } 
  else if (lightLevel >= darkThreshold && lightLevel < brightThreshold) {
    digitalWrite(redLedPin, LOW);
    digitalWrite(greenLedPin, HIGH);
    digitalWrite(yellowLedPin, LOW);
  } 
  else {
    digitalWrite(redLedPin, LOW);
    digitalWrite(greenLedPin, LOW);
    digitalWrite(yellowLedPin, HIGH);
  }

  delay(100);
}