Data Sheet

UCTRONICS Ultimate Starter Leaning Kit for Raspberry Pi #K0064
9 www.uctronics.com
 DATA: MCU IO port
 Digital signal output
 Tips: Do not reverse the VCC and GND, otherwise it will burn
3.3 HC-SR04 Ultrasonic Distance Sensor Module
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
3.3.1 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 40kHz sound wave and detector detects 40 kHz sound wave and sends electrical
signal back to the micro-controller.