While I was looking into method to get DC current on my oscilliscope I discovered this is an expensive hobby.
You can get DC current probes, for high currents. But what if you want to measure milliamps?
So I thought, why not make one?
Now, the immediate problem that arises when you're using a shunt is that the scope ground lead will be mains earth referenced.
This would mean that high side, or in-circuit measurements are a problem. I could think of three possible solutions to this.
1. Isolation amplifiers (AMC1100).
2. Isolated Sigma Delta modulators and an analog filters. However, I'm not sure if this would work reliably.
3. High common mode voltage amplifiers. (INA200, up to 80V)
I found one device on Tindie that looked like what I would want. Except not quite suitable for high side.
Simply put, I want to make a uCurrent with a BNC plug on it that can have some common mode voltage.
Would this be a suitable project? Or is it a rabbithole?
-- Update --
Well, rabbithole it is.
My efforts so far are on github, and I did some 3D modeling to see if it would fit in an enclosure.