Interface ultrasonic sensor HC SR04 with Arduino

Last Updated on March 24, 2024

Simple Interface ultrasonic sensor (HC-SR 04) with Arduino, The HC-SR 04 is famous ultrasonic range sensor, and its very easy to use with many microcontrollers. This article will give you idea about to interface ultrasonic sensor with Arduino board.

Here the circuit constructed for to identify the range limit with warning beep sound. This circuit have minimum components such as Arduino development board, ultrasonic sensor HC-SR 04 and a buzzer.

Connection diagram 

arduino ultrasonic

Circuit Diagram


This circuit can used for security alarm, invisible fence with alarm or distance measurement (Cm) etc…
The HC-SR04 sensor module works under the principle of ultrasonic wave transmission and ultrasonic wave reflection (echo). The time difference between transmitter wave to echo wave is calculated for to find the distance between sensor module and objects.

Arduino code

HC-SR04 Ping distance sensor
VCC to arduino 5v GND to arduino GND
Echo to Arduino pin 9 Trig to Arduino pin 8
Buzzer +ve to Arduino pin 13 and GND to GND
Original code sourced from
Some code and wiring inspired by

#define trigPin 8
#define echoPin 9
#define Buzzer 13
void setup() {
Serial.begin (9600);
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
pinMode(Buzzer, OUTPUT);


void loop() {

digitalWrite(trigPin, LOW);
digitalWrite(trigPin, HIGH);
digitalWrite(trigPin, LOW);

int duration = pulseIn(echoPin, HIGH);
int distance = (duration/2) / 29.1;

if (distance < 30)
digitalWrite(Buzzer,HIGH); //less than 30cm then buzzer will produce beep sound

else {

if (distance >= 200 || distance <= 0)
Serial.print("Out of range");
else {

Components List

1.Arduino UNO board1
2.Buzzer 6V1
3.Connecting Wiresas required



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