SenseTech Liquid Level Sensor
The SenseTech Liquid Level Sensor is available in two versions namely the Ultrasonic Liquid Level Sensor and the Capacitive Liquid Level Sensor.
The Ultrasonic version measures the distance from the sensor which is located at the top of your reservoir to the liquid surface. It then calculates the level using calibrated values.
The Capacitive version utilizes the principle of the change of capacitance of a simple wire when submerged in different mediums. The sensor then uses calibrated values and accordingly calculates the level.