How To Interface HC-SR04 Ultrasonic Sensor With Arduino UNO

SUPPLIES AND COMPONENTS

Connecting an Arduino to an HC-SR04 sensor

We can begin attaching the HC-SR04 ultrasonic sensor to our Arduino now that we fully comprehend how it operates!

The HC-SR04 is relatively simple to connect to Arduino. Put the sensor on your breadboard first. Connect the ground pin of the Arduino to the ground pin of the VCC pin. Now connect the trig and echo pins to the corresponding digital pins #9 and #10.

You ought to have something that likes the example below after you're finished.

Connecting an Ultrasonic Sensor to an Arduino UNO in Normal Mode 

Installing a library

It takes a lot of work to manually trigger the ultrasonic sensor and measure the pulse width of the received signal, but fortunately, there are several libraries at our disposal. The NewPing library is one of the most well-liked ones. We will utilize this library in our examples.

Navigate to Sketch > Include Libraries > Manage Libraries to install the library. Allow Library Manager to refresh the list of installed libraries and download the library index.

                              

Enter "newping" to narrow your search. Select Install after clicking the first entry.

Example Code for an Ultrasonic Sensor

Here is a simple sketch that uses the serial monitor to display a distance measured in centimeters. Give this sketch a try before we start a detailed analysis of it.

// Include NewPing Library
#include "NewPing.h"

// Hook up HC-SR04 with Trig to Arduino Pin 9, Echo to Arduino pin 10
#define TRIGGER_PIN 9
#define ECHO_PIN 10

// Maximum distance we want to ping for (in centimeters).
#define MAX_DISTANCE 400  

// NewPing setup of pins and maximum distance.
NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE);

void setup() {
  Serial.begin(9600);
}

void loop() {
  Serial.print("Distance = ");
  Serial.print(sonar.ping_cm());
  Serial.println(" cm");
  delay(500);
}

Open your serial monitor and adjust the baud rate to 9600 bps after the sketch has been uploaded. Try aiming the sensor at nearby things that are laying about. The calculated distance should start to stream soon.

Code Explanation:

The recently installed NewPing library is first incorporated into the drawing.

// Include NewPing Library
#include "NewPing.h"

The Trig and Echo pins of the HC-SR04 are connected to the designated Arduino pins first. A second constant, MAX DISTANCE, has also been defined. Pings sent beyond the specified maximum distance will be interpreted as "no ping clear." Currently, MAX DISTANCE is set at 400 [default = 500cm].

After that, a sonar-named instance of the NewPing library is built.

#define TRIGGER_PIN 9
#define ECHO_PIN 10
#define MAX_DISTANCE 400

After that, a sonar-named instance of the NewPing library is built.

NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE);

Following that, the first instance of the NewPing library is generated.

void setup() {
  Serial.begin(9600);
}

We only use the ping cm() method in the loop and output the outcome on the serial monitor. The distance in centimetres is returned once a ping is sent using this method.

void loop() {
  Serial.print("Distance = ");
  Serial.print(sonar.ping_cm());
  Serial.println(" cm");
  delay(500);
}

Additional features of the NewPing Library

You may utilise a few helpful functions with the NewPing object.

The distance is displayed in millimetres in the above drawing. Use the sonar.ping in() method if you want the result to be in inches.

Serial.print(sonar.ping_in());

The resolution of the aforementioned drawing is just one centimetre. Use NewPing in duration mode as opposed to distance mode to receive the result in decimal form. This line needs to be changed:

Serial.print(sonar.ping_cm());

along with line

Serial.print((sonar.ping() / 2) * 0.0343);

To increase the accuracy of your HC-SR04, use the function ping median(iterations) in the NewPing library. This approach averages the remaining values after discarding out-of-range readings and taking many measurements as opposed to just one. It only takes five readings by default, but you may set any number.

int iterations = 5;
Serial.print((sonar.ping_median(iterations) / 2) * 0.0343);