I am currently working on sensing the current used by a robotic device. Consider that I am also using external filters and trying different methods to try to get rid of the noise. The idea is to get a “clean” current signal here, but that is made difficult by the amount of noise I am dealing with.
So I decided to build this mini circuit (see attachement) in order to find out whether or not my Arduino (motor shield) itself is contributing to that noise. As you can see in the schematic, I am using a gain 10 Opamp to amplify the signal that I am sending through the 0.1Ω sense resistor. This amplified signal is then monitored using the analog pin A0. The signal that is being send through the sense resistor is alternating on/off, meaning that I turn pin 3 HIGH for about 0.25 sec then turn it LOW for another 0.25 sec and so on and so forth…
After testing it, I realized that I was getting very small numbers (ranging btw 0 and 4). My guess is that the input signal sent trough pin 3 is pretty low. Any idea on what the magnitude of the signal I am sending through RSense is? I would also welcome any other alternatives of the same purpose.