Arduino Tutorial: Dog Door Buzzer

This Arduino tutorial will use a photoresistor and a piezo buzzer to create a buzzer for your dog door to know when your best friend comes and goes. A photoresistor is a light-controlled variable resistor whose resistance  decreases with exposure to light. As your dog passes through the door, the photoresistor’s resistance will decrease and cause thepiezo buzzer to sound.

 

Components:

1 Arduino Board

1 Breadboard

1 Photoresistor

1 Piezo Buzzer

1 10K ohm resistor

1  6” USB A/B cable

Hookup Wires

 

Directions:

1. Start off by placing your photoresistor on the breadboard. Connect a wire from the 5V source to the photoresistor. Place a 10k Ω resistor on the other pin of the photoresistor. Connect a wire from the resistor to the A0 pin and a wire from the other leg of the resistor to the ground of your Arudino board.
2. Connect a wire from digital pin 7 to the piezo buzzer on the breadboard. Be sure to ground the Piezo Buzzer.

3. Open the Arduino software and create a new sketch; then upload the code below into the sketch:

int rcvpin=A0;

int buzzpin=7;

 

void setup()

 

{

 

pinMode(rcvpin,INPUT);

 

pinMode(buzzpin,OUTPUT);

 

buzz(200);

 

buzz(200);

 

buzz(200);

 

delay(2000);

 

Serial.begin(9600);

 

}

 

void loop()

 

{

 

int ldrval=analogRead(rcvpin);

 

Serial.println(ldrval);

 

if(ldrval>=500)

 

{

 

buzz(50);

 

}

 

}

 

void buzz(unsigned char time)

 

{

 

analogWrite(buzzpin,170);

 

delay(time);

 

analogWrite(buzzpin,0);

 

delay(time);

 

}

 

4.Connect a USB A/B cable from your computer to the Arduino. Click “Upload” in the Arduino program to run your sketch.

 

5.To test your code, cover the photoresistor to buzz the piezo buzzer.