Looking at the Ergodox PCB

A project log for Aerodox

[WIP] Keyboard based on Ergodox. But wireless?

Simon MerrettSimon Merrett 05/10/2020 at 23:410 Comments

The Ergodox uses a stagger in the keyboard columns, rather than the conventional row staggers. Columns are at the standard 19.05mm spacing (which I learned from here) and are staggered to match the length of your fingers, so the keys for your index finger are furthest away and those of your little finger are closest to the near edge of the keyboard.

The key switch footprints intrigued me. They are meant for  "standard" Cherry style switches but I don't know what kind of switch I'll settle on yet, so I need to make sure I can remove switches. Although you can get 

I also had to find out about LEDs built into key switches and even the diodes to enable matrix scanning can be integrated. Combined with differing numbers of locating pins, this results in a lot of holes for each switch. 

The ergodox keyboard is also nifty in that it can be reversed to allow the same PCB to be populated either as the right hand or left hand half. One aspect of the existing PCB bothered me and that was if the routing between the switch and the diode is standard, why aren't those traces built into the foot print? Surely with a 76 key board (so 38 per half) having these traces pre-routed in kicad would make layout quicker and simpler? One aspect which makes this slightly more complicated is that the diodes mean we can't just link the top layer up with the bottom layer. I managed to find out someone who claimed to know which way round the pre-installed diodes go in Cherry switches. Might as well go with that convention:

Well after several hours playing around, I can't find a way to have the footprint behave as if it is pre-routed and still accept traces on the main PCB. Hopefully I'll give up soon and I can concentrate on my edge cuts.

Talking of edge cuts, I think I'll use the recess between the thumb switches and the top of the keyboard as my hacking area. PCBs are priced by their rectangular perimeter and filling this area with my electronics won't prevent me from moving the keyboard halves any closer together than the existing design.