(1) Using IO trigger for at least 10us high level signal, (2) The Module automatically sends eight 40 kHz and detect whether there is a pulse signal back. (3) IF the signal back, through high level , time of high output IO duration is the time from sending ultrasonic to returning. Test distance = (high level time×velocity of sound (340M/S) / 2

Water Level Sensor Depth of Detection Sensor for ArduinoOperating voltage: DC3-5V Operating current: less than 20mA Sensor Type: Analog Detection Area: 40mmx16mm Operating temperature: 10℃-30℃ Humidity: 10% -90% non-condensing