Hi everyone, just another quick update to show this project isn't dead yet. Ive now properly implemented the link functionality, allowing the sd card to seamlessly connect to a computer. Using a V30 sd card I was able to get 30MB/s easily, definitely fast enough for what I need at least. I also put together a simple case to make development easier but it needs a bit of refinement.

You can see the slot for the master battery power switch, the sd card slot and volume rocker

This is the clickwheel design, its got two little hooks to clip on to the encoder and a gimbal mechanism that allows all the buttons to be pressed without stress on the encoder. The axles are just the legs of 1/4W resistors. It does work but the tolerance is a bit too loose so its a bit clumsy. Ive been testing a couple different resins to find one that has the right properties for the job and each has different tolerances.  This means clickwheel is resin printed, I did try a lot with many designs trying to make fdm work but the scale is just impossible.

Currently I am occupied with life but the next things on the list are:

• Comprehensive file explorer and playlist configurations stored on sd card
• Handling switching between audio decoders, audio playback logic
• Clickwheel tolerances and resin selection

Currently verified as working:

• Display 
• Esp32
• Usb hub
• Sd card reader
• Codec audio out and microphone
• Sd card data and power switches
• All buttons and switches can be read
• Programming circuitry
• Encoder
• SD card detection

Unverified

• Battery power operation
• Battery undervoltage cutoff
• Battery isolation switch
• Fuel guage (the library is unreliable)