OptoShield LED too bright / major hardware issue

[gergelytakacs]

@Gabor7697 has found out that the LED in the OptoShield is too bright, causing resolution and calibratin issues. At 5/255 analogWrite levels the sensor ouput is 900/1023; reducing resolution. Moreover according to him:

• The 10 k resistor for the LDR divider is not optimal, he calculated 2.3 kOhm (see below).
• A different colored LED can also help to reduce output.
• Larger LED resistor could reduce power.

All of the solutions above should be possibly tested.

@Gabor7697's calculations on a possible change in the LDR voltage divider.

The feedback process (because of the bad ranging) is not very nice, looks something like this:

[gergelytakacs]

@Gabor7697 pls. talk to @TiborKonkoly on possible HW changes when you can.

[Gabor7697]

Ok.

[gergelytakacs]

@Gabor7697 and @TiborKonkoly have patched the shield successfully. @TiborKonkoly should (after his thesis) modify the remaining boards. Do not forget to update any documentation, e.g. the wiki!