How to Use an Ultrasonic Sensor

This project will show you how to use an ultrasonic sensor with an Arduino.

What is an ultrasonic sensor?

An ultrasonic sensor is a module which uses ultrasound (you didn't expect that, did you?).

It allows to detect a presence or to measure a distance via ultrasounds.

He sends an ultrasound pulse via his trig terminals and receives them via his echo terminals.

The ultrasonic sensor sends 8 pulses of 40KHz via the trig terminals (inaudible to humans, it's ultrasounds).

The ultrasonic pulses collide an object and leaves in the other direction.*

The echo terminals receives the ultrasound pulses and the sensor calculates the distance based on the time of the pulses.

Speed of the ultrasounds: 340 meters per second.

Code

We will use the serial monitor with this line of code:

Serial.print("Distance in cm : ");

The serial monitor is a separate window that will appear when you click on the button " serial monitor " top right.

The serial monitor is used for receive or send data to the Arduino card.

So the program will print on the monitor " Distance in cm: " and the distance after.

Note : this window can't be clear so you must close it to clear what you write.

Connections

I don't find ultrasonic sensor in Fritzing for the schematics so I will say the connections here:

Pin 11 (Arduino) -----> Echo

Pin 12 (Arduino) ------> Trig

GND (Arduino) -------> GND (Sensor)

5V (Arduino) -----> VCC (Sensor)