This is a mini sump pump with very low water level actuation for a basement.

I used a 3d printed arm a diaphragm pump (which seems to be able to handle dirt inhalation no problem), a 12 volt power supply (3 amps, to deal with the start up surge ok), a 5 mm connector jack, and a mosfet switch module, and a float switch. All parts are available on amazon, the arm can be 3d printed. I wish they would give the actual cad file but it works well enough.

I made a custom end for the arm, only took a few minutes and yours will have to be different probably, so no point in uploading it.

The switch requires the mosfet module to turn the pump on because it can't handle enough current, and also it turns off when the float rises, not on. I added a resistor that pulls the input to the mosfet high, and then the switch connects to ground. Thus, when the switch is on, the NPN mosfet is *off*.

Whoops, there is more to add but not enough space.