Does anyone have ideas about a possible battery placement on this board?
Basically title.
Because I live in Paris, it would be nice to buy batteries in store. The most promising model I found is a 180mAh 32x17x4mm lipo.
I could also theoretically use one of these li-ion cylindrical batteries, but they are longer than the keyboard's size (which is 77mm).
Here's what I already tried:
removing the inner thumb key, which makes the keyboard 34-key and leaves enough space for the battery mentioned above. Though after a few hours of using home row mods on my current keyboard I don't think that will be a good solution.
moving the MCU (Seeed XIAO BLE) to the right, which makes the board 2cm wider (and doesn't look very good since I have no keys there). This one isn't very elegant, plus I don't really want to make the board wider, and I'd like to avoid it even though it is a solution.
Please ignore the mounting holes and TRRS jacks, I am still unsure about whether or not I want to just ditch bluetooth and make this board wired (which works with kmk)
The ergogen config is available on the github repo.
A printed case with about 30 degrees of tenting would provide a good bit of space under one side of the board. I did that with a Sofle RGB so I could fit a full PlayStation controller battery under it.
Yeah, at first it seemed quite alright to do with a smaller angle (from 3 to 6 degrees depending on the battery), but now I think it would make the board too complicated. Right now I am trying to get used to sticky mod keys on home row combos (colemak A+S for LGUI, N+I for LCTL) and it seems like I'll be able to remove the inner thumb key in the end.
about a year ago, SouthPawEngineer was playing with and talking about the advantages of coin cell batteries (really easy to get hold of) – should be able to wedge a small coin cell in the space to between the (nominal) ‘Z’ key and the thumb cluster …
EDIT: oh, and it would go on top of the board so no worries about clearance underneath and the coin cell should definitely not be higher than a choc switch + keycap
Thanks, great suggestion! But as it seems it would make use of less common parts (I mean parts that can't be gotten from local shops or ergo keyboard part sellers like splitkb), plus I think the batteries would be too small even compared to the 80mAh batteries used with nice!nanos.
unfortunately, using a Xiao makes this approach less than ideal. The Xiao's battery connector is a pad on the back, reducing the amount of space a battery can fit.
Since you're going hotswap, you've already got about 3mm of space on the back of the PCB. if you make your case just a tad taller, your battery could fit under the PCB.
I'd like to keep the board as flat as possible, mimicking the TOTEM's case which doesn't add any height. This means I'll have 0.2 mm between the main PCB and the bottom plate, and AFAIK there is no battery that would have the correct size for this.