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controlling many switches from the PC

Discussion in 'Electronic Basics' started by [email protected], Dec 2, 2004.

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  1. Guest


    I would like to control arund 100 electric switches from my PC.
    Can someone guide me on this.

    Thanks in advance

    Arun Sahlam
  2. Bob Masta

    Bob Masta Guest

    You can do this with the standard parallel printer port.
    It's easier if your system uses Win9x or DOS, but should
    work from NT,2K, XP with an IO driver so you can get
    access to the port.

    The standard port has only 8 output lines, but it also
    has several control lines. The trick is to make a multiplexer
    8-bit latch chips. Use 4 control lines to select one of 16
    latch chips to be updated from the common 8 lines.
    That will give you 8 * 16 = 128 possible outputs.

    There is lots of port info at

    Hope this helps!

    Bob Masta

    D A Q A R T A
    Data AcQuisition And Real-Time Analysis
  3. Bruce Robin

    Bruce Robin Guest

    Try reading up on X10 at They have a controller that attaches
    to your PC and the switches you'll need.
  4. Maurine O.

    Maurine O. Guest

    well how do you want to control them.? and what sort of switches are
    they.? and what do they control.?, what kind of hardware do you have
    hooked up to your computer at the moment.???......You could use a
    microcontroller to do this, but some information regarding your
    existing infrastructure would be useful
  5. wkearney99

    wkearney99 Guest

    I would like to control arund 100 electric switches from my PC.
    This like asking "How can I get to work?"

    What sort of switches, what sort of electric devices, what voltages, what
    wattage, what distances, etc..

    Ask better questions and you'll probably get better answers.
  6. JL Hart

    JL Hart Guest

    There is a book, perhaps out of print, from TAB books "Building Your Own
    Universal Computer Interface" by Bruce Chubb, that would provide a bunch
    of outdated information to get you started. The ISBN # is 0-8306-3122-4.

    Also, a look at the data sheet for an 82C55 programmable interface
    controller is interesting for historical content. It will point out the
    many good reasons for using a micro controller.

    Maurine's questions are also valid. On what level of interface are you
    looking to implement? Parallel port? Serial port? Mother board plug-in
    card? Speed?
    Then comes the question of user interface software on the PC. Is this
    something that you would prefer "off the shelf", or will you develop
    this application software?
  7. VKY

    VKY Guest

    If you want industrial strength safety and ease of use, go with an I/O
    card that you can plug into your PC. There are many vendors, and is one of the popular ones. The others you
    would have to google.

    Most of these cards have multiple output options including relays and
    SSR that you can use to control almost anything. They also have drivers,
    samples and everything you need to get going fast.

    Hopes it helps,

    Thomas Yip
  8. jim dorey

    jim dorey Guest this might help, and you
    might go nuts and use a tcp stack chip too. but you could just use a
    stack chip and get a matrix of 256 switches from it anyway.
  9. Si Ballenger

    Si Ballenger Guest

  10. Anthony

    Anthony Guest

    (Bob Masta) wrote in

    I did this with my very first computer for a science fair project back in
    83....a Tandy Color Computer....had a whopping 16K of extended
    memory...but more had a game port...
    I built a card to plug in the port..used opto-isolators...through some
    latches..and on to some high-capacity triacs..would switch 16 120VAC
    loads...I just hooked up 16 lamps for the project...but you could have
    ran your household appliances from it.
    BTW...I've still got the old color computer :)

    You can't 'idiot proof' anything....every time you try, they just make
    better idiots.

    Remove sp to reply via email
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