Styr (3A/250V) när en av två sensorer löser ut.

Circuit LM324 main control chip, the four LED display circuit, relay modules, metal induction module.
The level controller can use metal strips to sensing liquid level height, maximum reservation is in hell.
can through the control relay control water pump water (or water drainage),
when add the liquid to the specified level control relay pump stop working.
The height of the liquid level can be according to the design of the four bright LED lights to judge.