This US-100 ultrasonic module can realize 2 ~ 450cm of non-contact ranging function, has 2.4-5.5V of wide voltage input range, static power consumption is less than 2mA. Their own temperature sensor will revise the ranging and has many communication modes like GPIO, serial ports etc, just like watchdog inside, very stable and reliable. The US-100 Ultrasonic Distance Sensor Module operates from a wide voltage range and provides both digital and serial data output modes. The US-100 features accurate temperature corrected range detection. It can output the distance in millimeters using a serial data output mode. In this example we are going to connect to HC-SR04 and or US-015 ultrasonic sensor. (Updated 18. Oct 2015, adding US-015 sensor and sensor specs) (Updated 18. Apr 2016, adding more info for accuracy for the HC-SR04 sensor) A ultrasonic sensor will send ultrasonic sound out which will echo on objects in-front of it and come back to the sensor.