Using Ultrasonic Distance Sensor HC-SR04 with Buzzer, LED and Arduino

In this Arduino Tutorial we will learn how the HC-SR04 Ultrasonic Sensor works and how to use it with Buzzer and LED.

Required Hardware
Arduino Board:
Ultrasonic Sensor HC-SR04 :
Breadboard:
Jumper Wires:

Recommended Items:

Connections:
The HC-SR04 Ultrasonic Module has 4 pins, Ground, VCC, Trig and Echo. The Ground and the VCC pins of the module needs to be connected to the Ground and the 5 volts pins on the Arduino Board respectively and the trig and echo pins to any Digital I/O pin on the Arduino Board.

The HC-SR04 sensor attach to the Breadboard
The Sensor VCC connect to the Arduino Board +5V
The Sensor GND connect to the Arduino Board GND
The Sensor Trig connect to the Arduino Board Digital I/O 9
The Sensor Echo connect to the Arduino Board Digital I/O 10

Buzzer and LED
The Buzzer attach to the Breadboard
The Buzzer long leg (+) connect to the Arduino Board Digital 11
The Buzzer short leg (-) connect to the Arduino Board GND
The LED attach to the Breadboard
The Resistor connect to the LED long leg (+)
The Resistor other leg (from LED's long leg) connect to the Arduino Board Digital 13
The LED short leg (-) connect to the Arduino Board GND

Social Media:

[Kona-bona]

i had this project as an exam in my informatics class, and it worked and i got straight A. thank you.

[mrbowlingalley]

3 years later and we are still building this. I set safetyDistance to 25. With only LED and no buzzer. Detects my cat coming in the room. Pretty cool - I guess!

[alvaronicolasgamarrapena]

really good video man, code is great and when i tried it worked the first time, keep the great work bro

[AR-dyfu]

If anyone has any problems to get the code...just copy mine.


// defines pins numbers const int trigPin = 9; const int echoPin = 10; const int buzzer = 11; const int ledPin = 13; // defines variables long duration; int distance; int safetyDistance; void setup() { pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output pinMode(echoPin, INPUT); // Sets the echoPin as an Input pinMode(buzzer, OUTPUT); pinMode(ledPin, OUTPUT); Serial.begin(9600); // Starts the serial communication } void loop() { // Clears the trigPin digitalWrite(trigPin, LOW); delayMicroseconds(2); // Sets the trigPin on HIGH state for 10 micro seconds digitalWrite(trigPin, HIGH); delayMicroseconds(10); digitalWrite(trigPin, LOW); // Reads the echoPin, returns the sound wave travel time in microseconds duration = pulseIn(echoPin, HIGH); // Calculating the distance distance= duration*0.034/2; safetyDistance = distance; if (safetyDistance <= 5){ digitalWrite(buzzer, HIGH); digitalWrite(ledPin, HIGH); } else{ digitalWrite(buzzer, LOW); digitalWrite(ledPin, LOW); } // Prints the distance on the Serial Monitor Serial.print("Distance: "); Serial.println(distance); }


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[lecongquyen]

What a great detailed guideline! I followed step by step and it work. I will use it for my final electrical engineering project. Thanks a lot!

[muhammadfirdauz]

NICE!!! Saved me a thousand dlrs in school fees

[AVolt]

thank you so much it worked with me.

your fan from middle east
اخوك من الشرق الاوسط

[shlb]

OMG it works
thank you so much, please keep sharing projects like this.

[jwf]

// defines pins numbers
const int trigPin = 9;
const int echoPin = 10;
const int buzzer = 11;
const int ledPin = 13;

// defines variables
long duration;
int distance;
int safetyDistance;


void setup() {
pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
pinMode(echoPin, INPUT); // Sets the echoPin as an Input
pinMode(buzzer, OUTPUT);
pinMode(ledPin, OUTPUT);
Serial.begin(9600); // Starts the serial communication
}


void loop() {
// Clears the trigPin
digitalWrite(trigPin, LOW);
delayMicroseconds(2);

// Sets the trigPin on HIGH state for 10 micro seconds
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);

// Reads the echoPin, returns the sound wave travel time in microseconds
duration = pulseIn(echoPin, HIGH);

// Calculating the distance
distance= duration*0.034/2;

safetyDistance = distance;
if (safetyDistance <= 5){
  digitalWrite(buzzer, HIGH);
  digitalWrite(ledPin, HIGH);
}
else{
  digitalWrite(buzzer, LOW);
  digitalWrite(ledPin, LOW);
}

// Prints the distance on the Serial Monitor
Serial.print("Distance: ");
Serial.println(distance);
}

[theelectromaker]

Thank you very much, i saw many vids but any of them din't work but your worked thank you very much.

[Ganondalf_the_grey]

got the uno and this is a great tutorial. thanks.

[melihapa]

Hello. There are already a lot of these examples on youtube. In your circuit the lights are either on or off. The sound either squeaks or it doesn't. I wish you had made a circuit where the intensity of sound and light increases as you get closer. :(

[chaturbhujbiyani]

wow...u did it ....u saved me....i used it in science project...

[quentinb]

It came in a kit, first thing that I acutally got to work with my UNO. Thanks for thie vid.

[LhorKhan]

hi, can you explain where did you get this value 0.034?

Edited:
i did a google search, its the speed of sound (343 m / s)

[dylansworld]

Great project! Why is my buzzer clicking instead of buzzing though?

[mohdnaqibhaiqal]

I lke the video because is short and easy to understand

[nurinqasrina]

Why my led keeps on and the sensor is not working 😣

[AdityaYadav-mkye]

Thank you very much i am starting to learn arduino and thanks to you i can learn the hardware and then i will work on software

[marcelnalewajko]

Thank you! This tutorial was very good and helped me a lot