Working Principle - Uctronics WIFI Smart Robot Car Kit User Manual

Smart WIFI Robot Car Kit for Arduino
The HC-SR04 ultrasonic sensor module for Arduino is used for obstacle detection. Ultrasonic
sensor transmits the ultrasonic waves from its sensor head and again receives the ultrasonic
waves reflected from an object.
Ultrasonic sensor general diagram

2.1.1 Working Principle

The ultrasonic sensor emits the short and high frequency signal. These propagate in the air
at the velocity of sound. If they hit any object, then they reflect back echo signal to the
sensor. The ultrasonic sensor consists of a multi vibrator, fixed to the base. The multi vibrator
is combination of a resonator and vibrator. The resonator delivers ultrasonic wave generated
by the vibration. The ultrasonic sensor actually consists of two parts; the emitter which
produces a 40 kHz sound wave and the detector detects 40 kHz sound wave and sends
electrical signal back to the microcontroller.
Ultrasonic working principle
The ultrasonic sensor enables the robot to virtually see and recognize object, measure
distance and avoid obstacles. The operating range of ultrasonic sensor is 2 cm to 450 cm.
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