
Description:
This project creates a distance sensor alarm like the backup distance buzzers in cars. The closer an object gets to the sensor the faster the buzzer beeps. This project can be connected to a battery pack and work without being connected to a computer.
Parts:
- Arduino Uno
- Ultrasonic Distance Sensor
- Piezo Buzzer
- Breadboard
- Wires

Code:
- This is a continuation of the Arduino – Ultrasonic Distance Sensor project.
#define buzzer 7
#define trigPin 8
#define echoPin 9
long duration;
float distanceCM;
float distanceInch;
void setup() {
pinMode(buzzer, OUTPUT);
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
Serial.begin(9600);
}
void loop() {
digitalWrite(trigPin, LOW);
delayMicroseconds(2);
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
duration = pulseIn(echoPin, HIGH);
distanceCM = duration * 0.034 /2;
distanceInch = duration * 0.0133 /2;
Serial.print("Distance: ");
Serial.print(distanceCM);
Serial.print(" CM - ");
Serial.print(distanceInch);
Serial.println(" Inches");
if(distanceInch < 20){
digitalWrite(buzzer, HIGH);
delay(50);
digitalWrite(buzzer, LOW);
delay(distanceInch * 10);
}
}
Code language: PHP (php)
Code with Comments:
//define buzzer pin as digital pin 7
#define buzzer 7
#define trigPin 8
#define echoPin 9
long duration;
float distanceCM;
float distanceInch;
void setup() {
pinMode(buzzer, OUTPUT);
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
Serial.begin(9600);
}
void loop() {
digitalWrite(trigPin, LOW);
delayMicroseconds(2);
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
duration = pulseIn(echoPin, HIGH);
distanceCM = duration * 0.034 /2;
distanceInch = duration * 0.0133 /2;
Serial.print("Distance: ");
Serial.print(distanceCM);
Serial.print(" CM - ");
Serial.print(distanceInch);
Serial.println(" Inches");
//use an if statement for the buzzer to limit the distance for detection.
//IF distance is less than 20 inches turn buzzer on
if(distanceInch < 20){
digitalWrite(buzzer, HIGH);
delay(50);
digitalWrite(buzzer, LOW);
//delay loop for distance in inches x 10. This gives pause that changes the beeps
delay(distanceInch * 10);
}
}
Code language: PHP (php)