HC-SR04 Ultrasonic Sensor Distance Measurement Module for Arduino UNO PICAXE Microcontroller

Main features:
1. New HC-SR04 ultrasonic sensor distance measurement module
2. It has 4-mode connections: VCC / trig (T) / echo (R) / GND
3. With 0V to 5V electrical frequency output signal
4. It has high precision up to 3mm
5. Power supply 5VDC
6. The detection distance is from 2cm to 450cm

Working principle of the module:
1. Adopt IO trigger by providing at least 10us sequence of high level signal
2. The module automatically sends out eight 40kHz square waves and automatically detects whether it receives the return pulse signal
3. If there is a return signal, through the high-level emission and the high-level continuation time is the time of that from ultrasonic transmission to reception