Capacitive water level sensor
A number of methods can be used to determine the water level in a tank. One simple method, often used by cheap Arduino modules, such as the module depicted below, are resistive, meaning they measure the resistance between electrodes placed in the water. The more water covering the electrodes, the lower the resistance. This resistance can be easily converted to an analog voltage, which can be read by a microcontroller such as an Arduino. However, the problem with such sensors is that it requires passing a DC current through the water, which will cause corrosion on the electrodes. Over time, this changes their characteristics and can cause the sensor to stop working. On the other hand, a capacitive sensor passes no direct current through the water and works by measuring the capacitance between the sensor's electrodes. Sensor construction The capacitive water level sensor uses a layer of aluminum foil wrapped around a PVC pipe for the outer electrode and an insulated wire pulle