Method of use: A control mouth hair a 10 US above the high level, can wait for high level output receiver mouth. A has an output can open timer time, when the mouth into a low power can be read at ordinary times timer values, where you for the ranging time, can calculate the distance. This will continue the cycle, can reach you move measurement value ~ ~ 5. Module working principle: (1) the IO trigger ranging, to at least 10 us high level signal; (2) module automatically send eight 40 KHZ of square wave, automatic testing if it has any signals return; (3) a signal to return to, through the IO output top level, the duration of the high level is from the launch ultrasonic returned to time. Test distance = (high level time * sound velocity (340 M/S)) / 2; US-100 ultrasonic ranging module this US-100 ultrasonic ranging module can realize 2 cm ~ 4.5 m non-contact ranging function, with a 2.4 ~ 5.5 V of wide voltage input range, static power consumption less than 2 mA, bring their own temperature sensor calibration on the ranging results, and has GPIO, serial ports and so on many kinds of communication mode, inside take watchdog, stable and reliable.