That was quick! – It’s amazing what’ll come to you at random moments.
I was looking at some uneven fitting panels on a car earlier today and wondered, ‘why can’t the gaps be smaller?’ –
Well, my first idea is to simply see what happens when the gaps between the keycaps are smaller……..
If there’s no room for keycaps to wiggle, they won’t wiggle! – that’s the theory anyway – Prototype is on the printer as I type.
If this ‘rough and ready’ bodge works, I can knock out a more elegant solution that’ll look much better :-), it’ll involve going right back to the beginning, but…ho-hum, such is the nature of product development!
The idea is currently on the printer! – this is a ‘zero cost’ solution that may reduce keycap wonkyness to a level that’s acceptable.
The next idea introduces double the 3D printed parts and some extra parts on top of that – BUT, it’s still a very cheap solution compared to the alternative…..
Bleugh.Biz Blog Thingy 
I’m curious about the underside of the keys. Assuming the switches have squared edges, wouldn’t is be easy enough to just extend the part of the key that touches the switch and have ot go around the edges of the it? Like this -> https://ibb.co/8Ntc0rT <- Or is that how you're doing it already?
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It’s not easy finding ‘not round’ switches to stop them from spinning.
Well, there are a few on the market…BUT, at 4 times the cost of the ones I’m using!
Extending the edges down is something I’m kinda trying also – it may be that a second PCB sitting over the top of the existing one could give suitable lines to sit against…but tolerances are very tight.
I’m also going to try making the keys a little larger printing the keys a bit further apart so I can put them on the keyboard even closer together.
The print surfaces are quite smooth so provided I get the supports correct, it could work!
Right now, I’m printing them exactly as they would sit on the keyboard, so can only get about 0.25mm between them.
If I spread them out by 1mm, I can make each larger so the clearance becomes just 0.1mm!
After those ideas I’m ‘done’ but there’s at least 4 ways of achieving it
Thankyou for your input!
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How about something similar to how some older keyboards did it, kind of the way game controllers prevent the nuttons from spinning… https://ibb.co/KzmYb06 3d print a guide for the keys that would sit between the caps and the pcb? or is everything too small for that sort of thing?
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Everything’s a bit too small / not quite enough depth.
Realistically, whatever I do needs to fit in <2mm depth and around 5mm square!
I’m trying with some Mylar sheets at the moment , it’ll be a plug in type thing,
The bases sit on the switches, ther mylar sheet holds the bases in place and the switches sit on top.
I’m currently trying to lower depth a little to get the Mylar sheet sitting below the a500mini case.
I’ve not put too many specifics up at the moment as there’s another keybaord in development, so, I’d like to be first and make it harder for them to copy what I’m figuring out :-p
After that, it’ll all be mostly open, except the keycap STL’s and the PCB gerbers
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One last idea, just stick some holes in the main pcb and add protrusions on the keys that drop through those holes? I’ll shut up now and wait patiently like everyone else 😛
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Thankyou for your ideas, one has given me a little thought to approach in a different way 🙂
I had to dismiss holes quite early on as they’d need to be fairly large to have longetivity.
And that then causes issues with the switch and routing.
I ‘might’ be able to make 1mm wide dowels on the underside of the switch – but resin is quite easy to snap at that thickness.
The idea with a Mylar sheet could be modified though, instead of a sheet with lots of holes, maybe a PCB with just 1mm wide lines spaced apart. I don’t need to limit both vertical and horizontal, just one.
If I print the keys a little wider than taller, a PCB could limit the up / down twist, and the keycaps themselves will stop the left / right twist!
Thanks for the extra work I gotta do figuring this out now :-p
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Bit late to the ideas from the above comment. I was going to suggest similar to pins but tabs that hang under the key that rest in parallel to the switch. The tab would rest against the side of the switch body so no rotation could occur. Pins could also just be clipped off bits of wire to get around material weakness.
If all else fails then they make 2x1mm tiny magnets in each key side so they hold alignment to the row. Plus adding magnets is pointless fun.
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