I am making a project and I need to measure the current going from and to a micro motor found in the SG90 servo.
As in reply #5 and #8 in the link, I need to use a shunt and op-amp to amplify the voltage drop across the shunt.
However, because the current can go in both ways (turning the motor CW / CCW), how do I deal with negative voltages?
Can I use a bridge rectifier and then use a diode to detect which way the current is flowing? I guess then amplifying and using a differential configuration would be easy (and maybe uses only one op-amp)?
I've used the EasyEDA simulation to try and do this but I'm not sure if this circuit (partially completed) is good enough. (Note that V1 and V2 on the right are the pins that will go to the op-amp).
Although, if the entire thing could be done with an op-amp or two, that would be much better than over-complicating stuff.
Any explanation/clarification is appreciated!