Introduction: Sonar

In order to do this project you will need:

-Four Wires

-Arduino Uno

-Ultra Sonic Module

-This sensor measures the distance between it and another object.
-The setup requires to have a wire connected to each of the pins of the sonar sensor.


-Connect the VCC connector using a wire to the 5V located on the Arduino UNO board

-TRIG to the desired pin on the Arduino board(for example pin 9)

-ECHO to the desired pin on the Arduino board(for example pin 10)

-GND to GND on the Arduino UNO board


-before setup() you must initialize the pins along with the sensor_value and float duration(you'll need it later)

int TRIGpin=9;

int ECHOpin=10;

float duration=0;

int Sensor_Value=0;

void setup()

-you must set up the pins by doing pinMode(10,OUTPUT) and pinMode(9,INPUT) with Serial.begin(9600)

void loop()

-Inside the loop, you must send a LOW and HIGH signal, to the output pin, using digital write command and in between, there must be a delay of 2 seconds and a delay of 10 seconds after. You can you the delay() command or the delay microseconds command

- now you must have a duration command that will allow values measured by the sensor to be "spit out" at equal intervals. The setup will look like this:


now you need to serial print the value and now you're done with the setup.


- In order to calibrate the sensor, take measurements at a certain distance, for example, every 2 inches with multiple tests for each inch.

- take the average and find the equation of it using y= ax+b.

- now the only new code you'll need is to indicate that duration is the x and the distance is y along with initializing distance in the setup

New Codes


int distance


Data Table

Trial 1 Trial 2 Trial 3 Average

4inch: 587 593 641 590

6inch: 860 911 911 894

8inch: 1281 1239 1228 1247

10inch:1513 1489 1507 1503

12inch:1791 1788 1794 1791

The line of best fit: y=0.007x+0.016


4) To indicate if the door is open, put the sonar right up against the door while it is closed. If the sonar reads 0 inches then it is closed. Anything higher means it is opened.

Final Code
int TRIGpin=9;

int ECHOpin=10;

float duration=0;

int distance;

void setup() {






void loop()







duration= pulseIn(ECHOpin,HIGH);