Low cost membrane keypad prototypes?

Hi Dave,

Have you tried Permark? They are usually very competitive on pricing.

Andy

Would it be possible to sandwich some 0.6mm FR4 with holes punched in it over the PCB board contacts and then another layer of 0.6mm FR4 or mylar with thin carbon rubber dots glued to it. Then it would be a matter of getting the top layer screen printed with the characters of the buttons or the copper layer etched and plated with the numerals.

"David L. Jones" a écrit dans le message de news:

9zzHl.35008$ snipped-for-privacy@newsfe04.iad... 600$ seems already a good pricing. Alternatively capacitive sensing can be a zero-tooling solution, as it could allow to design your keyboard as a simple PCB and overlay it with any kind of decorative layer (laser-printed, etc). See solutions from Cypress (capsense), Microchip and others.

Friendly yours, Robert Lacoste

Thanks. Yes, I was already considering the Atmel Qtouch, but the keys are densely packed (6mm spacing) so although it might work, I suspect there might be quite some development to perfect it, and then there is the possibility of some people having issues with it. Anyone have any experience with touch technology at that spacing?

Thanks Dave.

I've used Entech a lot in the past. Quality has always been good. Pricewise they seem to be in the middle.

"David L. Jones" a écrit dans le message de news:

1FCHl.93328$e snipped-for-privacy@newsfe03.iad... 6mm spacing will definitevely be challenging...

Why would this be better than a plastic top cover with conductive pads? PCB toolings would not be much cheaper than printed plastic covers.

I have used:

I printed my own overlays and used:

to attach it to the keypad.

I would not use this for a permanent solution, but its looks good for prototypes.

don

You could just put individual tact switches on the PCB; it'd be quite labor-intensive until you go to pick&place.

Cheers! Rich

6 mm from key to key? Isn't that, like, 1/4"? I know of people whose fingertips are bigger than that.

Good Luck! Rich

Yep!

Yep!

But in the case of my project such a spacing is a necessity.

Dave.

Yeah, thought of that, but then I need the graphic overlay anyway, as I don't really have space above the keys on the PCB silkscreen.

Dave.

Thanks for the manufactuer links everyone, will check them out.

Regards Dave.

Dave's talking about a complete custom membrane keypad for very small quantities, doing it all as pcbs will save the 600 buck tooling cost.

You can print flat plastic cover at very low cost. Tooling is necessary only if you make doomed contact area. PCB (FR-4) is too rigid for doomed contacts and can not be printed with color. FR-4 is generally more expensive than plastic. I would use as small as possible FR-4 between bigger plastic cover and base.

A graphic overlay is almost trivial - a piece of plastic and a silk-screen.

Cheers! Rich