HC-SR04 Ultrasonic Sensor Module
Ultrasonic Sensors are used to find the distance of an object/obstacle in front of it. The sensor operates at +5V and consumes less than 15mA. Theoretically the sensor claims to have a measuring distance of 2cm to 450cm. However a range upto 80cm can be easily achieved practically.
The accuracy of this ultrasonic/distance sensor is 3mm and the covering angle is less than 15 degree.