HC-SR04 User Guide
Part 1 Ultrasonic Introduction
1. 1 Ultrasonic Definition
The human ear can hear sound frequency around 20HZ ~ 20KHZ, and ultrasonic is the sound wave beyond the human ability of 20KHZ .
1.2 Ultrasonic distance measurement principle
Ultrasonic transmitter emitted an ultrasonic wave in one direction, and started timing when it launched. Ult...
