2pcs Ultrasonic Module HC-SR04 Distance Measuring Transducer Sensor with mounting bracket for Arduino Uno, Mega, Raspberry Pi, Robots, etc.

Description

4 pins: VCC (5v) , Trig, Echo, GND. The module performance is stable, measures the distance accurately up to 2mm precision. From 2cm to 450cm away. <15 degree angle. Can be used for security system to detect object that wasn't there before. Calculate Distance with: distance = (time of the high electrical level * speed of sound (340M / S)) / 2