I made a macro keypad with 3D-printed switches

https://incoherency.co.uk/blog/stories/3pct-keyboard.html

by jstanley • 6 years ago

150 37 6 years ago

incoherency.co.uk

manbash• 6 years ago

The switch fits in a 14mm square hole (apart from the protruding wires), which is the same size as a Cherry MX switch, but the total height from the bottom of the switch to the top of the keycap is almost twice as large, about 45 mm vs 25 mm [...] This directly translates to increased keyboard height, so it would be good to cut this down as much as possible. I should be able to lose 2 mm from the wire support at the bottom of the switch, and another 1 or 2 mm in the height of the leaf spring attachment, but there's no way it's going to be as thin as the Cherry MX.

It's a nice concept but the design of the switch doesn't intend this project to replace your keyboard.

A nice design nevertheless :)

jstanley4• 6 years ago

It's easy, just cut a hole in your desk to accommodate your over-sized keyboard!

archarios• 6 years ago

Could use a height adjustable desk and a book as a mouspad. That's what I do for my keebs that are too tall lol

m0xte2• 6 years ago

Those contacts will oxidise almost instantly. From running morse keys for years, you need gold or phosphor bronze.

jstanley4• 6 years ago

Thanks, I will keep an eye on this. Do you reckon gold plating would suffice or is it likely to get worn away?

blackfawn• 6 years ago

Gold electroplating can utilize some relatively nasty chemicals such as cyanide and cobalt but some ways are more safe than others. You could more easily and inexpensively nickel plate it with household materials (and a nickel plating layer is often used as a flash layer for gold plating anyway.)

Simply tinning the copper with solder would likely be the easiest option although I couldn't say how durable that would be against contact wear over very long periods of time. I'd suspect just as durable as nickel or gold plating would be...

mdszy• 6 years ago

Gold plating is used a lot in electronics contacts to prevent corrosion, it's a pretty proven method that should work just fine without wearing away easily. As far as I understand it, the gold chemically bonds to the metal it coats, so it's not easy to wear it away.

russdill• 6 years ago

Might give more flexibility to move to optical sensing and avoid the contact issue entirely.

m0xte2• 6 years ago

Best to buy gold plated wire off the shelf for your design. Solders nicely as well!

I played with gold electroplating pens but they are nasty.

ezconnect• 6 years ago

Search google for optical keyboard switches, they are easy to 3D print. They have clicky designs and just sliders for quieter operation.

pehtis• 6 years ago

Gold plating wont cut it. It is a very thin layer of gold around the copper and it would wear out pretty fast. I'd recommend bronze.

econcon2• 6 years ago

It's a good project.

If you print a lot, here's my project using which you can create tons of cheap filament:

https://medium.com/endless-filament/make-your-filament-at-ho...

If anyone can contribute diameter control algorithm, please let me know!

regularfry2• 6 years ago

Is it the control algorithm you're after, or an output diameter measurement technique? You don't mention how you're measuring the width at the extruder die or after the freeze bath.

econcon2• 6 years ago

Hello! I've dual axis laser micrometer which has a sampling rate of 100 of times per second.

I can use microcontroller to read the measurements and want to dynamically change the puller roller speed. (It's a geared down stepper motor)

Pinch roller (puller) is very simple, it uses steel rollers which have sandpaper pasted (with epoxy) on it for gripping fimament - it can pull with force of 10kg before it slips.

I want to achieve tolerance range of +/-0.02mm in diameter

grooverut• 6 years ago

You mentioned the contours on top of the keycap being an issue. A good fix for that is tilting the keycap forward 45 degrees in your slicer. This does require supports but the top finish looks so much better. The tilt technique combined with your filament should look very good.

rolleiflex• 6 years ago

I caught the same issue, from a slightly different angle. Using key caps with that much protrusion surface will render them unsanitary in a relatively short time due to dead skin deposits, which will cure and fill the ridges. It’s not great from a health point of view. From what I remember when I was doing 3D printing, an acetone cloud bath could help to achieve a more glossy, thus more sanitary finish.

Incidentally glossy finish on porcelain-ware for plates, bath tubes, toilet bowls and sinks are specifically for this reason — gloss is achieved when the surface is flat to a defect rate smaller than the wavelength of visible light, which also gives bacteria and organic matter very little to hold on to.

biggerfisch• 6 years ago

Usually acetone doesn't work so well on the PLA the author is printing the keycaps in. There are other sprays or things you can apply to PLA for a good effect though - I'm betting any of the things used to make PLA food-safe would work here.

Okkef• 6 years ago

Don't get me wrong, I'm heavily into the custom keyboard scene. PCB design, lots of tiny soldering, 'crazy' ergonomic layouts with only 36 keys and lots of layers and other tricks.

Still. Why would you want to print your own switch mechanism?

gh02t• 6 years ago

Fun/learning. This is actually quite a sophisticated engineering challenge and there is a ton of stuff to be learned. I would love to do this if I had the time.

enchiridion• 6 years ago

I view projects like this along the same lines as maintaining classic cars. It a fun and rewarding project, and you learn things along the way.

Pixelbrick• 6 years ago

There is a yak, and it is furry.

EForEndeavour• 6 years ago

For the uninitiated: https://en.wiktionary.org/wiki/yak_shaving

1. Any apparently useless activity which, by allowing you to overcome intermediate difficulties, allows you to solve a larger problem.

I was doing a bit of yak shaving this morning, and it looks like it might have paid off.

2. A less useful activity done consciously or subconsciously to procrastinate about a larger but more useful task.

I looked at a reference manual for my car just to answer one question, but I spent the whole afternoon with my nose buried in it, just yak shaving, and got no work done on the car itself.

nkrisc2• 6 years ago

The same reason people build and fly model airplanes even though it would be impossible to transport a financially viable amount of cargo on them. It's fun.

JoeSmithson• 6 years ago

Neat project - next time make one with only ctrl, alt, and del.

iDemonix• 6 years ago

I've been undertaking a similar project, using an ESP32 currently for testing, also have an Arduino Micro Pro to test yet, during lockdown/furlough. I'm hoping to customise and sell them on Etsy, I've sold code + 3D prints before, but I'm just taking time to get the PCB right before I get my first ever board printed. Aiming for hot-swappable switches and some LED magic.

delgaudm• 6 years ago

Inspiring! This would be an awesome punch-and-roll macropad for voice actors... well, this particular voice actor anyway. I currently use a 10 key pad with tape covering all but the three keys I want to press.

aidenn0• 6 years ago

One possible improvement would be to include space for mounting a diode. Many mechanical switches can house a diode to simplify PCB layout for NKRO keyboards

I made a macro keypad with 3D-printed switches

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