Scissor-switches needed for custom made gaming keypad

[keypad_steve]

Hello everyone.

 
I'm designing a gaming keypad for use with first person games. I've made a 3D CAD model and printed it out using a 3D printer.

For the next stage of the project some key switches are needed but I'm having trouble finding any that have a suitable specification for the requirements. They need to have between 2 and 2.5mm of travel and will (probably) require between 4 and 7 newtons of force to operate. Scissor switches would be preferable because they have a responsive and tactile feel which would be good for gaming but other types of switches will also be considered.

I've looked at switches available from Mouser, DigiKey, RS and Farnell but non are suitable. Can anyone here offer any help or advice?


Many thanks in advance,
Steve 

[jdcarpe]

Cherry ML switches, maybe?

400-700 cN actuation force, eh? Wow.

[dorkvader]

I think MLs might work well, especially since they have a tactile feel. Other than that, a microswitch with a small lever might be perfect to get a little more travel out of the microswitch.

4-7N is extremely high, roughly an order of magnitude more than a "normal" keyboard. You could get some custom springs made for a ML switch or something. If you can 3D print, a custom hall effect switch over custom springs could work as well. You might have to du custom leaf springs or beam springs or something to get that amount of force. I'll think on it.

To compare, a normal rubber dome keyboard is about 85-120 cN at actuation (all the way down), and a normal mechanical is about 50-80 cN at actuation (roughly halfway down.
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To DIY scissor switches would be quite hard. You could do carbon contact switches over PCB without too much difficulty, but getting a custom membrane made will prove difficult.

Hope this helps and letus know of updates! I'm interested for sure! I made a custom gaming keypad and I love mine.

[keypad_steve]

Cherry ML switches, maybe?

Ooooh yes they look good! That could be just what I'm looking for. 

They might be a bit deep to physically fit in it though. The distance from the bottom of the keyboard to the top of the lowest key (the 'space bar' button) is only 17mm. How deep are MX switches?


There is a low profile flat version of their switch which is just 6.9mm deep. It has a bit more travel than I wanted but a slight redesign of the keys would overcome that problem.

http://www.cherry.co.uk/cid/keymodules_ML1A-xxxx.htm?

400-700 cN actuation force, eh? Wow.

My mistake. I ment 40-70cN.

[keypad_steve]

I think MLs might work well, especially since they have a tactile feel. Other than that, a microswitch with a small lever might be perfect to get a little more travel out of the microswitch.

Yes I think ML switches might be the best option. 

4-7N is extremely high, roughly an order of magnitude more than a "normal" keyboard. You could get some custom springs made for a ML switch or something. If you can 3D print, a custom hall effect switch over custom springs could work as well. You might have to du custom leaf springs or beam springs or something to get that amount of force. I'll think on it.

To compare, a normal rubber dome keyboard is about 85-120 cN at actuation (all the way down), and a normal mechanical is about 50-80 cN at actuation

Oops

I think I ment 40-70 cN rather than 4-7N. I'm new to all this and learning very quickly.

Hope this helps and letus know of updates! I'm interested for sure! I made a custom gaming keypad and I love mine.

Show Image

Nice keypad.  :cool:

It's a little bit similar to my design but due to having access to a 3D printer I can make custom shaped ergonomic keys.

[keypad_steve]

I made a custom gaming keypad and I love mine.

How did you make the circuit board for your keypad?

I was considering hiring an electronics engineer to custom design the one for mine.

[jdcarpe]

I made a custom gaming keypad and I love mine.

How did you make the circuit board for your keypad?

I was considering hiring an electrical engineer to custom design the one for mine. Are they easy to make?

That's half of an ErgoDox Keyboard.

[jacobolus]

Yep, I think Cherry ML is your best bet, since they’re modular.

[keypad_steve]

I've ordered some Cherry ML key switches and they are exactly what's needed for my keypay.

But I've also read that 'Topre' short throw keyboards are even better. Does anyone know what key switches are used in these Topre short throw keyboards?

[CPTBadAss]

But I've also read that 'Topre' short throw keyboards are even better. Does anyone know what key switches are used in these Topre short throw keyboards?

Check out this article here for some more information about Topre short throw switches. However, Topre switches aren't discrete individual switches like MX or ML switches which might complicate things. You'd have to design your own PCB to work with the Topre switches.

[keypad_steve]

Thanks CPT. 

Are there any other short throw (3mm travel or less) key switches that may be worth considering?

[jacobolus]

Thanks CPT. 

Are there any other short throw (3mm travel or less) key switches that may be worth considering?

Nothing really that’s still produced today. There used to be some other low-travel switches in the 80s.

[CPTBadAss]

You could try and find a board that has low-profile Alps which has a short travel. I had some in a Dauphin DCK84 keyboard I bought on eBay. Not sure if they're going to be easily sourced in any other way though.

[jacobolus]

Low-profile Alps switches, at least the tactile kind used in the Apple Adjustable keyboard, suck IMO. Maybe the linear ones are better.
http://deskthority.net/wiki/Alps_SKFR/SKFS

If you do want some though, this laptop uses some with black sliders, which might be the linear kind, and also looks like it has PBT dye-sub keycaps:
http://www.ebay.com/itm/390764607469

[Oobly]

Cherry G84 keyboards have ML switches and low profile uniform shape keycaps so you can put any cap on any switch, no need to make your own unless you really want to. you can find them quite cheaply on eBay. Probably a good deal cheaper than buying individual switches.

ML switches are quite "scratchy", but they can be lubed to improve the feel.

They're PCB mount only, so you can't mount them to a plate, but you can mount a plate under the PCB to stiffen it up.

Interesting related video:

Good luck with your project, please post a thread in "making stuff together!" if you find the time. I'm sure there are others who would be interested to see your project.

If you do open them up to lube them, it looks like they can also be trampoline modded to help dampen the bottom out feel and reduce the overall movement a bit if that's something that you're interested in: http://geekhack.org/index.php?topic=50632.0

IMSTO sells 2mm silicone balls which are perfect for the mod: http://imsto.cn/index.php?route=product/product&path=61&product_id=88

[keypad_steve]

Good luck with your project, please post a thread in "making stuff together!" if you find the time. I'm sure there are others who would be interested to see your project.

I'll post some pictures of the finished pad in due course along with details of the development process from start to finish. I'm currently working in conjunction with a local product design company to develop it into a working model to put on the Kickstarter website in the hope of raising enough money to put it into production.

Thanks to everyone here who has helped out. Your unique collective knowledge and input has been very useful. 

[adventurepoop]

If you use ML you can do a 1 layer pcb by the way, they have a bridge in them so that you can do that.

[keypad_steve]

If you use ML you can do a 1 layer pcb by the way, they have a bridge in them so that you can do that.

Yes I'd noticed that, it's one of the things that makes the ML switch a very attractive option to use. I'm very keen to keep things as simple and cheap as possible from both a design and manufacturing point of view while still keeping the build quality high.

The Cherry ML is a bit more expensive to buy than I was hoping for but the modular design and being able to use a 1 layer PCB simplifies things considerably. Using mechanical switches rather than scissor or other dome type also has the added benefit of a longer life and better reliability. The Cherry ML's have a very nice tactile feel for gaming on (even though they're not a particularly popular choice for regular typing keyboards I think they may be ideal for a gaming keypad).

Simplicity and keeping costs low without sacrificing quality is likely to be the key to success with this project. It's USP is the shape and layout which is very comfortable for both left and right handed people to use and it's ideal for use with the Oculus Rift virtual reality headset as well as desktop monitors.

[dorkvader]

The Cherry ML is a bit more expensive to buy than I was hoping for but the modular design and being able to use a 1 layer PCB simplifies things considerably. Using mechanical switches rather than scissor or other dome type also has the added benefit of a longer life and better reliability. The Cherry ML's have a very nice tactile feel for gaming on (even though they're not a particularly popular choice for regular typing keyboards I think they may be ideal for a gaming keypad).

Your best bet is finding a used ML Keyboard on eBay or the classifieds. Mine was $12 I believe.

I like them well enough for typing. The tactile aspect really helps.

[keypad_steve]

The Cherry ML is a bit more expensive to buy than I was hoping for but the modular design and being able to use a 1 layer PCB simplifies things considerably. Using mechanical switches rather than scissor or other dome type also has the added benefit of a longer life and better reliability. The Cherry ML's have a very nice tactile feel for gaming on (even though they're not a particularly popular choice for regular typing keyboards I think they may be ideal for a gaming keypad).

Your best bet is finding a used ML Keyboard on eBay or the classifieds. Mine was $12 I believe.

I like them well enough for typing. The tactile aspect really helps.

I've bought a set ML switches from RS Components already which I'm going to use in the first 3D printed model that has moving keys. I'll be working on the computer model over the weekend to incorporate the switches into the design.

The cost for a set of 28 switches that are needed for each keypad is about £12 (I'm in the UK) so while it's more than I wanted to spend it's still not excessive and the added simplicity and reliability will be worth the extra outlay. So long as the finished keypad can be manufactured and sold for under £30 I'll be happy.

I'll still looking at other options but the ML's are easily at the top of the list at the moment.

[samwisekoi]

<skip>
 I made a custom gaming keypad and I love mine.

Show Image

Woah!  What a brilliant use of an LH Ergodox!

Can you bring it out next weekend?  Please?  My thumbs have seen some ****, and keyboard/mouse gaming is often painful for my left hand, so I have been twisting a TKL around on my desk, but your gamepad would solve that problem completely!

See you (and hopefully this gem) soon!

 - Ron | samwisekoi

p.s.  I'll also see if I can hook you up with Retro DSA arrows, home, and end keycaps.