Buzzer with LDR and LED


Arduino basic tutorial for beginner. We will learn use buzzer, ldr and led with Arduino Uno.

Hardware Required:

- Arduino Uno
- Buzzer
- LED
- LDR
- 220 and 10K ohm resistor
- Wires
- Breadboard


Code :


//set pin numbers

const int ledPin = 13;
const int buzzerPin = 12;
const int ldrPin = A0;

void setup () {

  Serial.begin(9600);

  pinMode(ledPin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
  pinMode(ldrPin, INPUT);
}

void loop() {

  int ldrStatus = analogRead(ldrPin);  //read the state of the LDR value

  if (ldrStatus >= 400) {

    tone(buzzerPin, 100);
    digitalWrite(ledPin, HIGH);
    delay(100);

    noTone(buzzerPin);
    digitalWrite(ledPin, LOW);
    delay(100);

    Serial.println("----------- ALARM ACTIVATED -----------"); 
  }
  else {

    noTone(buzzerPin);
    digitalWrite(ledPin, LOW);

    Serial.println("ALARM DEACTIVATED");
  }
}