fixed compile error and corrected UI colors

[lucaji]

Hi Urs,

I just tested the code and I can compile it with Arduino IDE without any issues. The GetQMeasurement function is now back in the code and its being used as it was to avoid those drift you mentioned.

Regarding the UI LED colors I do not have the manual here at hand so I went from memory - and did cancel the previous PR as I noticed that the audio should be active at power on (if I remember correctly) and the RED LED indicates the audio active function while the BLUE is on during MUTE state.

Apologies for the delay - it's a busy time for me - hope all is well now, but let me know if any other issues arises.
Cheers,
Luca

[DitaXoXo]

Hello,
This version of the code works fine on my open theremin, but there is one issue with the sound being played when calibrating (playTone function) ; it will only be played when you pressed the calibration button with a blue led. For exemple :

red led -> start pressing -> led becomes blue -> wait UI_BUTTON_LONG_PRESS_DURATION -> playTone()
this would work and the tones would be played

blue led -> start pressing -> led becomes red -> wait UI_BUTTON_LONG_PRESS_DURATION -> playTone()
this wouldn't work and the tones wouldn't be played.

I have tried several things but I can't seem to make this work, sadly...