DROK Accurate Arduino Ultrasonic Distance Meassuring Sensor Module Solid build precise ultrasonic detection module with extra pins,accurate between 2cm~450cm Durable and easy to set up, requires DC 5V input voltage, quiescent current is less than 2mA Using IO trigger for at least 10us high level signal, effectual angle is 15 degree Automatically send eight "40 kHz "and detect whether there is a pulse signal back If the signal back, through high level,time of high output IO duration is the time from sending ultrasonic to returning