Ultrasonic Sensor Module HCSR-04

Description

Ultrasonic sensors measure object separation distance using ultrasonic waves.

The sensor head emits an ultrasonic wave and receives the wave reflected back from the target. Ultrasonic Sensors measure the distance to the target by measuring the time between the emission and reception. It generates high-frequency sound (above the human hearing range) waves. HC SR04 module provides for a detection range of 2-400cm, contactless measurement! The modules includes ultrasonic transmitter, receiver and a control circuit.

Working:

• An IO trigger for at least 10us high level signal
• The module automatically sends eight 40kHz pulses and detects whether there is a pulse signal back
• If there is indeed a pulse received, thru a ‘High’ on the ‘Echo’ pin, the duration (Time Elapsed) between the pulse triggered and received is measured and processed to arrive at the separation
• Distance = Time Elapsed × Velocity of Sound (340M/s) / 2}