PDA

View Full Version : Custom Made Keypad



MagicStamp
05-05-2006, 12:38 AM
Is it Posible to make your own keypad to interface with a basic stamp 2
i am unable to find the proper keypad for my project does anyone have any homemade keypad links?
i need to build it for·my own needs, by preference a membrane keypad
has anyone tried such thing?

THANKS A HEAD

Chris Savage
05-05-2006, 01:01 AM
You could build one out of pushbutton switches if you want.· The way a matrix is encoded is adequately posted and can be found via Google.· Basically rows and columns interconnecting in a specific manner.·

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage
Parallax Tech Support
csavage@parallax.com (mailto:csavage@parallax.com)

Beau Schwabe (Parallax)
05-05-2006, 01:12 AM
I have tried this before with mixed results. (<--Read we ended up finding a company that made membrane keypads)

What we tried and it worked ok, but you really had to push hard to get it to work, was basically two printed circuit boards
sandwiched together. One board(the bottom board) was a standard 1/16th inch PCB, the other board (the top board) was
a 1/64th inch PCB. A mylar insulation (5 mils ) was used in-between the boards with a 8mm circle cut in the mylar that
corresponded to the location of each switch. One board served as the ROW, and the other board served as the COLUMN.
A simple matrix key scan routine served for reading the switches.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Beau Schwabe (mailto:bschwabe@parallax.com)

IC Layout Engineer
Parallax, Inc.

MagicStamp
05-05-2006, 01:28 AM
i am asking this because while i was doing my research i stumbled on a prototype but never could get that link back thinking it was a common thing it was made using transparent plastic layers and
the rows and collums were made with what looked liked thin lines of copper sheets
do you guys think some thing like that would work ?

I dont think a single membrane keypad would be cheap if i have it made (WITH ALL THE LABOUR THEY MIGHT CHARGE). I looked at the prices they sure dont look cheap if you buy them one by one.

Beau Schwabe (Parallax)
05-05-2006, 01:40 AM
Copper adhesive foil could work I guess.

How many switches ere you talking about? ...And is there any kind of pattern regularity on how the switches would be placed?

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Beau Schwabe (mailto:bschwabe@parallax.com)

IC Layout Engineer
Parallax, Inc.

MagicStamp
05-05-2006, 01:53 AM
I guess it could be a basic 4x4 look but the important part comes in the distance from one key to the other. thats why i need to make my own. and i cant seem to find one in all those premade ones

southernbob
05-05-2006, 06:06 AM
Would this work to build a 'QTI touch sensor' keyboard? The info is here;

http://www.parallax.com/detail.asp?product_id=604-00038

It would be a 'little' expensive @ $4 x 16 but may work.

Bob

MagicStamp
05-09-2006, 12:51 AM
can any help me on this

Paul Sr.
05-09-2006, 01:46 AM
MagicStamp said...
can any help me on this


It looks to me like you have been given a LOT of help. You need to do SOMETHING yourself - that's how we learn!

MagicStamp
05-09-2006, 08:30 AM
i am willing to try this i guess

i·made my rows and collums using copper foil

guys have any ideas how to make copper foil to stick on a plastic transparent layer sheet ?

Beau Schwabe (Parallax)
05-09-2006, 10:18 AM
They make copper foil with adhesive backing already on it. If you don't have a local electronic store
nearby, you might be able to get it at a hardware store. Otherwise there are several places on-line
Digikey, Mouser, etc.

cgi.ebay.com/EMI-shielding-Copper-Foil-Adhesive-Tape_W0QQitemZ8278258933QQcategoryZ3099QQcmdZViewI tem (http://cgi.ebay.com/EMI-shielding-Copper-Foil-Adhesive-Tape_W0QQitemZ8278258933QQcategoryZ3099QQcmdZViewI tem)

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Beau Schwabe (mailto:bschwabe@parallax.com)

IC Layout Engineer
Parallax, Inc.