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Custom Made Keypad — Parallax Forums

Custom Made Keypad

MagicStampMagicStamp Posts: 10
edited 2006-05-09 03:18 in BASIC Stamp
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

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-05-04 18:01
    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.·

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • Beau SchwabeBeau Schwabe Posts: 6,568
    edited 2006-05-04 18:12
    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.

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    Beau Schwabe

    IC Layout Engineer
    Parallax, Inc.
  • MagicStampMagicStamp Posts: 10
    edited 2006-05-04 18:28
    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 SchwabeBeau Schwabe Posts: 6,568
    edited 2006-05-04 18:40
    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?

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    Beau Schwabe

    IC Layout Engineer
    Parallax, Inc.
  • MagicStampMagicStamp Posts: 10
    edited 2006-05-04 18:53
    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
  • southernbobsouthernbob Posts: 34
    edited 2006-05-04 23:06
    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
  • MagicStampMagicStamp Posts: 10
    edited 2006-05-08 17:51
    can any help me on this
  • Paul Sr.Paul Sr. Posts: 435
    edited 2006-05-08 18:46
    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!
  • MagicStampMagicStamp Posts: 10
    edited 2006-05-09 01:30
    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 SchwabeBeau Schwabe Posts: 6,568
    edited 2006-05-09 03:18
    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_W0QQitemZ8278258933QQcategoryZ3099QQcmdZViewItem

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    Beau Schwabe

    IC Layout Engineer
    Parallax, Inc.
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