Most encoders are open-collector, so try changing
pinMode(ChannelA_LEFT, INPUT);
pinMode(ChannelB_LEFT, INPUT);
pinMode(ChannelA_RIGHT, INPUT);
pinMode(ChannelB_RIGHT, INPUT);
to
...
You don't want sharp edges with a graphic equalizer normally, you want smooth transitions. The Q of the individual stages needs to match their geometric spacing. Sounds like you have one control per octave, and a Q of...
Well it appears to be a variable low pass filter and a power amp output. The LM386 hasn't been made for years, doubt you'll find one that's not a fake, perhaps a small class-D chip would be a suitable replacement?
...
The fast I2S signals (especially MCLK) might not be reliable with long jumpers like this, especially with all that loop area - bundle them all together if you can to improve signal quality. A large loop is an antenna,...
If you use only the full voltage from the battery and buck converter(s) you'll be able to change to a different power
source flexibly, as well as not unbalancing the cells.
Stencils are designed to be stretched taut in a stencil frame, the fact the stainless came off a roll (which is why they
have a curve) wouldn't normally cause issues used with a frame (might make storage an issue...
Perhaps a link to the datasheet for the parts in question? - better than trying to guess what "high definition"
might mean to you, 1000 PPR, 10000 PPR, or even more?
How many encoders are likely to be changing...
Python3 bytestrings are not the same as unicode strings (Python3 strings are unicode). A bytestring is notated b'xxxxxxxx'
Python3 strings can be interconverted <-> bytestrings if you give the encoding to use.
This...
ILI9341 is a chip, not the actual TFT display. This sort of thing is why you should try to find something with a decent datasheet.
I'm sure there's a lot of difference between different displays.
One thing you...
No, those signals are way too small to be fed direct to the ADC and get anything meaningful out.
An instrumentation amp is probably the way to go, though you'd need to ensure the potentials fall within its input...