water level detector schematics
I am making a motor controlling device for controlling the motor of a water pump.The motor is switched on and off by a relay depending on the level of water in a tank.
Wires are placed in the tank at different levels. When the water reaches the appropriate level the wires are shorted and the coil of the relay is activated and the motor is switched off.
The trouble is, I am having problem with conduction through water.The relay coil is about 400 Ω and it operates at 28V DC. The circuit works perfectly well when I short the wires manually but when shorted through water the coil does not activate.Why does this happen ? What do you suggest I do ? How can I make it work ?