Bob Rev 1 (Not built)

JLC PCB accepts revisions if you contact customer support quickly.
Ensure breakout pins are aligned to a 0.1" grid.
Ensure USB traces are correctly sized to get the correct impedance.
- This involves a lot of maths. Use a calculator.

Bob Rev 2

Screw switch has large thermal mass, so it needs to be soldered first.
- It is also large, so the nut should be located far away from other components so you can actually solder them.
- Eggtimer uses a brass nut, but I was able to get it to work with random M3s I found lying around.
  - Chromed or galved nuts don't work.
- Needs to have some form of shake-prevention, e.g. nylock or shakeproof washer.
- JLC fills hole with copper, which needs to be filed out.
- M2 is probably more reasonable.
- Aside from this, seems to work well as a detail.
0603's are the absolute smallest that can be soldered with "normal" soldering supplies.
- 0806 is probably more reasonable.
- 0402 is pain.
Hot air and flux make everything so much easier.
- Fluid tension pulls components into alignment in a very satisfying way.
- Flux doesn't hold QFNs that well, but heating the board and dropping the package on seems to work.
- Leaving flux on the board too long can tarnish the pads.
  - May affect reliability.
  - Is ugly as sin.
  - Pads can still be tinned, but the easiest solution is to not let it happen.
  - Clean board with IPA and and old toothbrush.
- 0402s have a nasty tendency to tombstone.
5032 crystals are hard to find.
Placing tight arrays of components is difficult.
JLC have an assembly option.