Ultrasonic Module Sensor HC-SR04   New
Nyereka Tech LTD
This is the HC-SR04 ultrasonic ranging sensor. It provides 2cm to 400cm of non-contact measurement functionality with a ranging accuracy that can reach up to 3mm. Each HC-SR04 module includes an ultrasonic transmitter, a receiver and a control circuit.
The ultrasonic Sensor uses sonar to determine the distance to an object
-The transmitter sends a signal to a high frequency
-When the signal found an object its reflected and transmitter (echo-pin) received it.