HC-SR04 Ultrasonic Sensor Ardunio tutorial
Components needed
for this tutorial
You can get these
components from any of the sites below:
- Ultrasonic Sensor HC-SR04
- Arduino BoardICStation
- Breadboard and Jump Wires
How
It Works – Ultrasonic Sensor
It emits an ultrasound at 40
000 Hz which travels through the air and if there is an object or obstacle on
its path It will bounce back to the module. Considering the travel time and the
speed of the sound you can calculate the distance.
The HC-SR04 Ultrasonic Module has 4
pins, Ground, VCC, Trig and Echo. The Ground and the VCC pins of the module
needs to be connected to the Ground and the 5 volts pins on the Arduino Board
respectively and the trig and echo pins to any Digital I/O pin on the Arduino
Board.
In order to generate the ultrasound
you need to set the Trig on a High State for 10 µs. That will send out an
8 cycle sonic burst which will travel at the speed sound and it will be
received in the Echo pin. The Echo pin will output the time in microseconds the
sound wave traveled.
For example, if the object is 10 cm
away from the sensor, and the speed of the sound is 340 m/s or 0.034 cm/µs the
sound wave will need to travel about 294 u seconds. But what you will get from
the Echo pin will be double that number because the sound wave needs to travel
forward and bounce backward. So in order to get the distance in cm we
need to multiply the received travel time value from the echo pin by 0.034 and
divide it by 2.
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