Ultrasonic Distance Measuring Sensor HC-SR04 for Micro Controller (Arduino, Raspberry etc.). Measuring range 2 – 400 cm, resolution 3 mm.
Very easy to use ultrasonic distance measuring. The small PCB contains ultrasonic transmitter, receiver, and control logic. 2 digital ports are needed to connect the sensor to a micro controller, an example sketch for Arduino is available in the download section below.
The operation voltage is 5V, power consumption just about 2mA. The measuring angle is about 15 degrees.