Pendant Membrane Switch Graphic

[vacpress]

Hello.

I have been trying to figure out a good way to make membrane switches. I want to make something like this test design i made into a pendant:




Anyone seen any sites about DIY membrane switches?

My current idea involves small PCB pushbutton switches, clear inkjetable window sticker material, and some sort of ridgid top layer with button cutouts.. so it would be a membrane switch under a shield, sorta... not exactly what i want..

i even foolishly loaded a sheet of thin white thermalplastic ive got into my inkjet and tried that - thinking i could make a mold and vacuum form a panel..


ideas?

[bkukowski]

What are your plans for interfacing that with a computer?
Are you designing custom electronics too to work with the rotarty encoder, and led's inside (I assume there's a power led, etc.)

My only suggestion would be to make a more basic 3 axis version as well, without A axis features or the f keys, probe and 2 aux buttons. The jog dial is excellent. I'd likely buy one.

EDIT: what about qtouch IC's? http://www.qprox.com/ I've used them and they're pretty cool. A qtouch rotary dial as well (like the ipod clickwheel) would be amazing. I don't know of a cnc pendant like that.

Edit2: here's a link specifically to the rotary encoder http://www.qprox.com/products/qwheel_qt510.php

[vacpress]

wow. it is $100..

i was planning a combonation of parallel port pins, keyboard output(via a usb keyboard PCB)... a mouse encoder or a simple slotted disc and optical sensor for the mpg...


cheap and easy. some of the LEDs are just for this version, as there will be several prototypes.

Printing on thermalformable plastic with inkjet... that is what i want, pretty much

[mxtras]

Vacpress -

I am not an electronics dude, but when you get moving, I want one. I can maybe pitch in for some of the R&D costs and help you out that way, but when it works I want to buy one - for sure. Keep me in mind - please!

Scott

[vacpress]

xtras-no prob...

in fact, if someone could cnc me a mold for vacuum forming some tests, they would compensated.. especially if they could 'support the development' which would be upto 3 or 4... hmm 10x12x.25 " 'molds'.... details to follow..

i would mail you a block of REN modeling board. a very nice material that cncs like wood but has a much more regular grain, being some sort of expanded foam...

im not sure... if i can find an easy way to make membrane panels, they could be cheap... other options would be pushbuttons and a milled faceplate with inkjet printed graphics sandwiched...

modern inkjets can produce very nice control panel art, i am sure.

[vacpress]

ya'know,

come to think of it, i dont even need a mold machined, i just need some sort of 'inserts' i can glue or tape down or something to make test panels..

ive got this idea that i can use some sort of flexible glue and tin or copper foil, glued into the 'top' of a 'pushbutton' molded into plastic.. when pressed it would hit a PCB below...

illustrations will follow.. i have been so busy.. incidently, i tried putting some pushbuttons under a piece of thin plastic with an inkjet printed transparency on top.. it was too difficult to press and the buttons had to be far apart, and it took alot of effort to make... an ideal assembly would be 2 or 3 layers... pcb, buttons of some kind, printed panel.. comercial makers use these weird metal things, but then i need to be able to mold an allready printed piece of plastic again..

Ugh. I am sure my long-windedness will kill my own thread.

[lwill]

You could try ripping apart an older caluclator or adding machine. I tore one apart once since it had stamped metal triangular shaped "domes" under the buttons, the 3 corners acted as one contact and there was a dimple in the center that was the other contact. Pushing in the center would make it sort of "pop" down in the middle and make contact.

Opps, just read vacpresses last post. Same thing.

Also chech out these very thin switches from ALPS
http://www.mouser.com/catalog/625/1167.pdf
I think they have a similar metal peice in them that you could maybe rip out and use in you own design.

[JavaDog]

You could always eBay some old 'Lights Out' games and scavange the really nice lit rubber switches from them. The only buttons you have on there that aren't square-ish are the 'manual control' sections.

Just find someone that can print on Adhesive Vinyl to do the overlay, and the buttons would come up through that...

[bkukowski]

Only the eval board is $100. The rotary touch IC itself is about $5-6. The alps switches look nice, it would be nice to feel a real click when you press the button.

[mxtras]

i would mail you a block of REN modeling board. a very nice material that cncs like wood but has a much more regular grain, being some sort of expanded foam....

I am familiar with it and I can (and am willing to!) do this kind of stuff if you don't get any other more attractive offers. I am also familiar with molding urethanes in small quantity, custom runs in 'budget' tooling.

I don't have any ideas for the electrical side of things but I am willing to pitch in for the mechanical and molding side of things to bring an attractive, functional package together.

Scott

[vacpress]

yes. i want it to be ultra simple... as much as can be done by etching a PCB and molding a single piece of plastic, ideally.. the comemrcial makers all have crosssections of their designs. unfortunately most seem to rely on either conductive ink printing, printing onto moldable plastic, or both..

the hard part, really, is printing on a piece of plastic which can then be molded.. a google search of 'inkjet vacuum form' and 'inkjet plastic' gave no good results.

[mxtras]

What about maybe using a water clear urethane skin and a thin nylon film behind,then mold together? Can you print on nylon film? Would it survive?

Just tossing out ideas... might not be good ideas but ideas none the less!

Look at the gas pump keypads - they are perfectly flat w/o bumps. What if you made a thin spacer to keep the contact film off the board and when the key area was depressed it made contact - you know? The face of the keypad could then be made flat and could open up a few more options.

Scott