EA asked:

How did you build this current sensor??
--

Its a circuit that I found on the internet years ago. Magnet wire is
wound around an iron core and placed near one of the wires to the pump.
A voltage is induced in the coil which is sensed by the circuit. I
can't send the circuit here.


---MIKE---
In the White Mountains of New Hampshire
(44° 15' N - Elevation 1580')