This ultrasound sensor is commonly found in many robotic projects. Cheap, it could be found quite easily on the market. This library as many others is willing to help you deal with it.
This popular ultrasonic distance sensor provides stable and accurate distance
measurements from 2cm to 450cm. It has a focus of less than 15 degrees and an
accuracy of about 2mm.
This sensor uses ultrasonic sound to measure distance just like bats and dolphins do. Ultrasonic sound has such a high pitch that humans cannot hear it.
This particular sensor sends out an ultrasonic sound that has a frequency of
about 40 kHz. The sensor has two main parts: a transducer that creates an
ultrasonic sound and another that listens for its echo.
To use this sensor to measure distance, a microcontroller must measure the
amount of time it takes for the ultrasonic sound to travel back and forth.
| HC-SR04 | Arduino |
|---|---|
| Vcc | Vcc |
| Trig | Arduino digital pin |
| Echo | Arduino digital pin |
| Gnd | Gnd |
It is possible to use the default pinout (echo: 2, trig: 3) on the library
by instanciating the sensor with no addtional arguments.
Ultrasound mySensor;However, you could define the specific pin you want to use. Checkout the code below for an example.
uint8_t echoPin = 12;
uint8_t rigPin = 13;
Ultrasound mySensor(echoPin, trigPin);It is possible to set the time frame in which we expect to get an echo back
to the sensor. This avoid waiting too long without response. So the timeout can
be set with this library as follow:
unsigned long timeout = 20000000UL; // 20ms
mySensor.setTimeout(timeout);To read the distance measured by the sensor, use the read() method.
unsigned int measure = mySensor.read();