README.feedback

The basic feedback measures the voltage on the output.
If it is too high, that means some gel has to be added.
The 3 LED display can be switch between the input level and the feedback.

However, if the level is low, the feedback is always good. It should be a display of the voltage divided by the requested current.

The trick is at levels around zero, the result should be always OK.

The voltage detection uses a 4 diodes bridges without compensation that keep to zero the 2 first volts on the primary. The lin-log-subtraction-lin way allow to compute, for instance, V/sqrt(I). A coefficient should be added and the sqrt should be something between 1 and 0.5 in order to fit a relevant scale of the display.

The actual design is experimental. Unfortunately, I don't have time yet to validate.

The PCB is design to be built with the full schematic. It is going to work or not.
To use the basic feedback, X207, X208, X209 and D211 should be removed, and the connection should be done on the FB_light pin.