Non-contact distance measurement using ultrasonic sound is widely used in real-life, for example in a radar or in a car reverse sensor. This is a sensor module that can be used to measure distance from an object by emitting inaudible ultrasonic soundwave and listening for the echo when it bounces back.
This module has a transmitter, a receiver and control circuit. For interfacing, it has 4 pins:
Vcc: Connect to 5V DC
Trig: Used to trigger the sending of ultrasonic pulse
Echo: Used to get the time it takes between sending the sound and getting back the echo (to and fro)
GND: Connect to ground
How to use the sensor:
Start the measurement by sending a 10us high pulse from a microcontroller to the Trig pin
The module will produce an 8 cycle sonic burst at 40 KHz
The module then send back via the Echo pin one high pulse. The duration of the pulse is how long it took between sending the sound and receiving back the echo
Using the speed of sound = 340 m/s constant, you can calculate the distance between the sensor and the object in your program. Distance = (high pulse duration x speed of sound) / 2
Take note that this is a 5V module. If you are using a 3.3V board (like a Raspberry Pi), you need a logic level converter or a voltage divider circuit to bring down the voltage.
