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How to emulate part of a keyboard?

Discussion in 'Electronic Basics' started by Eric R Snow, Oct 31, 2003.

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  1. Eric R Snow

    Eric R Snow Guest

    Greetings All,
    I am going to be installing a retrofit control on a cnc machine soon.
    All the motion commands come from a standard keyboard. I can buy a
    pendant control for $645 for this control but really can't afford it
    right now. What I want to do is jog the machine during setup and hold
    the small pendant, with just a few buttons, in my hand. Is there a
    way, for a novice, to use remote buttons to emulate buttons pressed on
    a standard IBM compatible keyboard? And, if this can be done, can both
    keyboards be connected to the computer at the same time or will I need
    to use a switch to go back and forth between one board and the other.
    Thank You,
    Eric R Snow
  2. Lord Garth

    Lord Garth Guest

    If you care to, you could use a multichannel RF remote and connect the
    receiver to a gutted keyboard via FET switches. Multiple keyboards are
    doable as well. How many buttons do you need? Ming makes a reasonable
    priced key fob and reciever.
  3. Eric R Snow

    Eric R Snow Guest

    I probably need 8 buttons. Rf is out of the question because of all
    the radio noise in the shop. This comes from welders and other cnc
    equipment such as dc spindle drives. However, using the coiled cord
    from a keyboard will give plenty of movement. I only need to get about
    5 feet max from the main keyboard. How would I use FET switches to do
    this? I can follow instructions or a schematic but have no idea how to
    hook this up.
    Thank You,
  4. Lord Garth

    Lord Garth Guest

    You need to get a working keyboard and either trace the keys you wish to
    remote through the keyswitch matrix or discover the pins on the controller
    that represent those keys. The FET switch would have its drain on one lead
    and its source on the other lead of those controller inputs. Assuming an
    N-channel FET, A solid high on the gate will cause the keyboard to transmit
    as if a button had been pressed.

    If you build the FET adapter neatly within the keyboard, you can then use
    the keyboard itself and the remote pendant eliminating the multiple keyboard
  5. Sockmonkey

    Sockmonkey Guest

    Is there a

    An i-pac ( might work for you. It is
    designed to hook arcade joysticks and buttons up to a computer using the
    keybord interface. You could use type of buttons up that you wanted. It is
    completely programmable, so you can make it correspond to whtever keys you
    need. It also has a pass through for the original keyboard.
  6. Eric R Snow

    Eric R Snow Guest

    Greetings Sockmonkey,
    I think that is exactly what I want.
    Thank You,
    Eric R Snow
  7. onestone

    onestone Guest

    A very simple way to do this yourself, for just 8 switches, is to use
    either a small crosspoint switch or a pair of CMOS quad switches. inside
    a keyboard you'll find a 16 x 8 ( 1X - 16X and 1Y - 8Y) matrix
    connecting the keys to the controller. It's yars since I've done this,
    and I couldn't find the key to track map, but it's easy enough, to trace
    by hand. Then wire each switch across the desired track pair. For
    example, if 'A' uses tracks 14X and 5Y you would solder the common of
    one CMOS switch to 14X and the N/O contact to track 5Y. Connect the
    control pin to your button via an R/C to debounce the contact.

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