Ultrasonic ranging sensor available at Tomson Electronics, Kochi, Kerala, India is an economical sensor module that 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.
There are only four pins that you need to worry about on the HC-SR04: VCC (Power), Trig (Trigger), Echo (Receive), and GND (Ground). You will discover this sensor simple to set up and use for your next range-discovering venture utilizing an Arduino or Raspberry Pi.