Small Keypads

[JohnSL]

Hi,

I'm working on a project that needs a keypad: http://model-railroad-hobbyist.com/node/30242

Right now I'm using the following keypad: https://www.itead.cc/electronic-components/button-and-switch/small-sealed-membrane-4x3-button-pad-with-sticker.html. This keypad has a very nice size for my application:  52 x 40 mm. Unfortunately, it's been retired. And all of the other keypads I can find are a little wider than my slightly less than 2.5" case will allow. So, I'm wondering if people have suggestions. I liked the feel of this membrane keypad, but I'm not wed to membrane keypads. I also liked the prices, which if I remember correctly, was about $2 each.

The only other option I've been able to identify is to contact manufacturers in China to see if they can make a keypad this size for not too much. I have no idea what the quantity will be for my product, so I don't want to order too many right away. I'm thinking of perhaps 1,000 pieces. Does anyone have experience having custom membrane keypads made in China?

Thanks,
  -- John

[richard.cs]

I wasn't involved personally but I know that at work we've had custom keymats made, any combination of buttons, LEDs and printing that you like. Whilst we've probably ordered many thousands now I have a feeling we get them in batches of 500-1000, certainly I would expect 1000 to be well over the MOQs.

I should be able to get the manufacturer's name on Monday if that's useful?

[JohnSL]

Thanks Richard, I would appreciate that information.

[LabSpokane]

If you can't make something work from China, you could even just get someone to make you an embossed polycarbonate overlay with self-adhesive that you could attach to a PCB with existing microswitches or metal snap domes.  It likely won't cost $2/ea, but the MOQs could be much easier. 

Your design is common enough that it might even fall into a manufacturer's samples tooling.  You'd likely just have to pay for silkscreens and cutting dies if you can't make their exterior dimensions fit. 

If you can fit everything on a 2-sided PCB using SMT, the switches could be the front side and the active circuitry could be on the back. 

If pricing forces you offshore, Kingley is one reputable supplier from a past life:  https://www.kingleytech.com/membrane-switch.htm

San Teh is another manufacturer from the past, but they specialize in elastomers, which also may fit your price point.  Keeping with the above, 2-sided philosophy, the elastomer keypad could be secured to your PCB with sort-of rubber posts, which would be pulled through holes in the PCB. You then have the option of microswitches or carbon pucks. 

http://www.san-teh.com/

[rdl]

AliExpress has some that look similar.

https://www.aliexpress.com/cheap/cheap-membrane-keypad-4x3.html

[LabSpokane]

rdl found your 52x40:  https://www.aliexpress.com/item/3x4-Matrix-Array-Membrane-Switch-Keypad-12-Key-4-3-4X3-Keyboard-3-4-Keys-Display/32802950007.html?spm=2114.40010708.4.71.B1XiDF

The big issue will be if you plan on buying an injection mold designed around someone else's "off the shelf" part.  There's no way you'll tool up and be at $1.63 per part, but your tool life will likely be about the same as the whims of your vendor and how long your safety stock of the keypad lasts.  Depending on the cost of the injection mold, you may choose to mitigate your risk and buy your own, proprietary keypad tooling at some point.