Below I have the following (simplified) circuit:
What I want is to measure (monitor) every time the relay switches on and off. The pulse is around 3V and for 32ms.
The problem is that the voltage is reversed, to switch off the relay (single coil latching), and I have no idea how to wire it correctly up with my Arduino.
One solution (not sure) I came up with is to use 3 wires. If I hookup GND with (Arduino) GND, and the A and B wires go both to its own port (with some pull-down resistors) on the Arduino.
I think it should also be possible to hook-up with only 2 wires (just A and B)? But, if I hookup A/B directly on the (Arduino) input ports, I'm basically hooking-up GND, that doesn't seem right.