Testing the HCNR201 linear optocoupler linearity on the new sensing board

Pretty linear results but I used the wrong Amp on the ESP side. The OpAmp used is not rail-to-rail but positive rail-1.4v. This reduces the resolution heavily. I will replace those with rail-to-rail Amps to bring back the full range from 0-3.3v.

[@PaulDominguez]

The interface looks really nice

[@G-EDM]

Display could be a little bigger but for now this is ok.