Early Planning Note

This was a file I had on my computer with some early ideas for this project:

Timer IC

MCU

eInk Display

This display is ~4mm over in the y direction, but it is very close otherwise
- Driver circuitry can be found on page 57 of this datasheet.
This one is smaller, but the whole design (components only, traces on back are fine) will probably be able to fit on to one side with it
- Chip datasheet not available separately, but the waveshare datasheet includes a circuit
- Seems to be IL0373, the Adafruit featherwing probably uses the same module

Battery

This is one of the tiniest rechargable SMT batteries (not replacable though), it is just over 2mm thick
capacitors won't hold charge for long enough
replacable coin cell that can fit, holder
all of these parts seem good, document also has charging circuit for battery

Solar

This part from TDK looks good
- Video showing usage and chip
This part is smaller, but it has easy to use wires
This chip looks useful, but only with higher powered solar module
- Like this one
Another analog chip
This one from TI looks good, is low cost, and is active for new designs unlike the analog one
- This one is simpler because it doesn't have non-rechargeable battery fallback but it costs more (maybe because it is smaller)
- Combine with a boost converter and TPL5111