int ledred = 10;
int ledyellow = 9;
int ledgreen = 8;
int buzzer = 11;
int ldr = A0;

void setup() {
  // put your setup code here, to run once:
  pinMode (ledred, OUTPUT);
  pinMode (ledyellow, OUTPUT);
  pinMode (ledgreen, OUTPUT);
  pinMode (buzzer, OUTPUT);
  pinMode (ldr, INPUT);
  Serial.begin (9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  int ldrstatus = analogRead(ldr);

  if (ldrstatus>250) {
    digitalWrite (ledred, HIGH);
    digitalWrite (ledgreen, LOW);
    digitalWrite (ledyellow, LOW);
    tone (buzzer, 1000);
    Serial.print("Too bright: ");
    Serial.println(ldrstatus);
  }
else if (ldrstatus<=250 && ldrstatus>100)
 {

    digitalWrite (ledred, LOW);
    digitalWrite (ledgreen, HIGH);
    digitalWrite (ledyellow, LOW);
    noTone (buzzer);
    Serial.print ("Ideal: ");
    Serial.println (ldrstatus);
  }
else
 {
    digitalWrite (ledred, LOW);
    digitalWrite (ledgreen, LOW);
    digitalWrite (ledyellow, HIGH);
    noTone (buzzer);
    Serial.print ("Too dim: ");
    Serial.println (ldrstatus);
  }

}