This is an easy to use long range ultrasonic distance sensor module. It can detect objects upto a distance of 700cm in front of it. Signals can be read from the 4-pin interface (Vcc, Trig, Echo, Gnd). One pin is used to trigger the ultrasonic transmitter and another one is used to read the echo. This US 015 distance sensor offers both accuracy and stable readings that is not affected by sunlight or object color.
The US 015 is a popular widely used ultrasonic sensor. Libraries are available for all popular microcontroller platforms in including Arduino. This allows you to directly connect the sensor to the microcontroller and start using it without much programming.