Detecting Obstacles and Warning - Arduino, Ultrasonic and Buzzer




Introduction: Detecting Obstacles and Warning - Arduino, Ultrasonic and Buzzer

This is tutorial to help you understand ultrasonic and buzzer and go
deeper into learning Arduino, follow these steps and give me feedback please.

I'm making it to help my cousin in his school project.

Step 1: Prepare Your Material and Tools

1. Test Board

2. Ultrasonic sensor

3. Arduino cable

4. +5V buzzer

5. Male to male pins

6. Arduino uno board

Tools and materials are shown in the pictures.

Step 2: Connect Your Circuit

Connect the Buzzer positive terminal to the Arduino pin 2 and the negative terminal to the Gnd.
Connect the VCC pin of ultrasonic to +5v pin and the Gnd to the ground.

Connect trig pin to pin 10 and echo pin to pin 9.

The pictures shows you the connection.

Step 3: Load the Code to Your Arduino

You can find code in here, it is well described and commented.
This is copy of the code any way.

This code should work to get warning cross the buzzer when something be closer than 0.5 meter

Circuit is ultrasonic sensor and buzzer +5v and Arduino uno is used

+201153300223 */

// Define pins for ultrasonic and buzzer

int const trigPin = 10; int const echoPin = 9;

int const buzzPin = 2;

void setup() {

pinMode(trigPin, OUTPUT);

// trig pin will have pulses output

pinMode(echoPin, INPUT);

// echo pin should be input to get pulse width

pinMode(buzzPin, OUTPUT); // buzz pin is output to control buzzering }

void loop() {

// Duration will be the input pulse width and distance will be the distance to the obstacle in centimeters

int duration, distance;

// Output pulse with 1ms width on trigPin

digitalWrite(trigPin, HIGH);


digitalWrite(trigPin, LOW);

// Measure the pulse input in echo pin

duration = pulseIn(echoPin, HIGH);

// Distance is half the duration devided by 29.1 (from datasheet)

distance = (duration/2) / 29.1;

// if distance less than 0.5 meter and more than 0 (0 or less means over range)

if (distance <= 50 && distance >= 0) {

// Buzz

digitalWrite(buzzPin, HIGH);

} else {

// Don't buzz

digitalWrite(buzzPin, LOW);


// Waiting 60 ms won't hurt any one



Step 4: Try It

Watch this video for it working, record you video and show me, give me your feedback and i love to answer your questions.

1 Person Made This Project!


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Question 4 years ago on Step 3

I want an arduino car kit to go and just like here when it comes to an obstacle for some distance then to stop and make sound and write on the display the distance. how can I do it, any link or source you advise?

electric guy
electric guy

6 years ago



6 years ago

please help me friend i want use a relay or something ( your recommend ) and 220v an alarm

Ammar Atef Ali
Ammar Atef Ali

Reply 6 years ago

Use relay it is easy, but first find suitable relay


6 years ago

how can use a relay not buzzer, i want to use 220v an alarm ?

Ammar Atef Ali
Ammar Atef Ali

Reply 6 years ago

It is recommended to use opto couplers instead of relays

put the input on it instead of buzzer.

If you need i can work on it for you, just tell me
Thanks for your comment