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Control 8 Electrical Devices With Your Parallel Port

Posted by timothy on from the fire-hazard dept.

Michael Williamson writes "A PC parallel port can provide 0 or 5v on 8 pins, individually controllable. This can be used to directly drive LED lights, or with the addition of an external power supply, some switching transistors, and some relays, control 8 higher-powered devices. I've written a handful of example programs that drive a homemade 8-LED display in amusing ways."

5 of 48 comments (clear)

  1. 8 Devices? How 'bout 256? by forsetti · · Score: 2, Informative

    With a few extra chips (decoders), it would be awfully easy to control 2^8=256 devices. Note that I said "control", and not "drive". You will definitely need some external power to drive this....

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    10b||~10b -- aah, what a question!
  2. Can be done with a serial COM too! by curious.corn · · Score: 2, Informative

    Take a diagram like this and add another line of FF on the outputs to mask the output while shifting... (say, DTR will shut them keep/thru, RTS to strobe... use CTS on a dead FF or buffer to sync for propagation delays) Heh, can you buy FF sticks anymore? it would be fun to play with...

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    Mi domando chi à il mandante di tutte le cazzate che faccio - Altan
  3. Why? by slacy · · Score: 0, Informative

    This is the kind of electronics project I was doing when I was about 12 years old. Why is this worthy of Slashdot? Pretty soon I'm just gonna stop reading this drek.

  4. Coffee by infernalC · · Score: 2, Informative

    There has been a HOWTO for controlling an automatic drip coffee machine for years using your legacy paraport. See Coffee HOWTO.

  5. Also, by Anonymous Coward · · Score: 1, Informative

    There are other neat computer chips out there that will light up LEDs or perform logical functions, or whatever you want. Start here.