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need help to build a card for driving 17 relays

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  • SADI Kheir-Eddine
    hi, well, i need to build an electronic card to drive 17 relays by pc and return two values read from 2 sensors. could any body help me please?
    Message 1 of 4 , Jan 8, 2004
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      hi,

      well, i need to build an electronic card to drive 17 relays by pc and return
      two values read from 2 sensors.

      could any body help me please?
    • multiuseguy
      Using three 74374 IC s and three ULN2803a IC s you can drive 24 relays utlilizing the control pins to select the 74374 chips via software. I m not sure about
      Message 2 of 4 , Jan 9, 2004
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        Using three 74374 IC's and three ULN2803a IC's you can drive 24
        relays utlilizing the control pins to select the 74374 chips via
        software. I'm not sure about the sensors.


        --- In home_electronics@yahoogroups.com, "SADI Kheir-Eddine"
        <mindoverflow@y...> wrote:
        > hi,
        >
        > well, i need to build an electronic card to drive 17 relays by pc
        and return
        > two values read from 2 sensors.
        >
        > could any body help me please?
      • xxxtoytech
        Look in the Files section of this group for a PDF document parallel.pdf along with PDF data sheets for most of the components required. This describes a
        Message 3 of 4 , Jan 9, 2004
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          Look in the "Files" section of this group for a PDF
          document "parallel.pdf" along with PDF data sheets for most of the
          components required. This describes a simple interface for sending
          and receiving data via the parallel port. It doesn't cost too much
          and takes about an afternoon to build. You'll notice that not all 8
          bits of the control signal are used. You can use the unused bits to
          control additional IC's (look at the schematic to see how each IC is
          addressed). Depending upon your relays you may be able to drive them
          directly from the circuit given. The only caution is that you'll have
          to read the values from the sensors a bit at a time so if the values
          are rapidly changing it might present a minor problem. It also
          depends upon the resolution of the sensor (binary, 4-bit, 8-bit etc.)
          The programming is also described; you can used most popular
          programming languages including Java to access the parallel port. You
          can also use an old PC that has been discarded for experimentation.

          Regards
          xxxtoytech
          --- In home_electronics@yahoogroups.com, "SADI Kheir-Eddine"
          <mindoverflow@y...> wrote:
          > hi,
          >
          > well, i need to build an electronic card to drive 17 relays by pc
          and return
          > two values read from 2 sensors.
          >
          > could any body help me please?
        • SADI Kheir-Eddine
          hi, well, the real application of that project isn t to drive 17 relays but to drive 17 electromagnets to simulate a punched card, the photocell is used to
          Message 4 of 4 , Jan 10, 2004
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            hi,

            well, the real application of that project isn't to drive 17 relays
            but to drive 17 electromagnets to simulate a punched card, the
            photocell is used to determine if the reader is reading the card or
            not. I think that the electromagnet can't function for a long time
            without taking a pause then i am planing to use a triger so that when
            the photocell's signal is moving from high to low, the electromagnets
            will be turned off and when it's moving from low to high, the
            electromagnets gets activated. what do you think about it? about the
            current sensor i think it's no more needed cuz we'll know if the
            reader is on or off by adding a timeout to the photocell, when it's
            reached the reader is considered as of until it sends that signal.
            then the pc will send 3 bytes containing wich electromagnets to
            activate and the board will send 1bit (in 1 byte) wich is sent when
            the photocell changes it's state and is used to synchronize between
            the pc and the reader. I'll write the software part.

            What do you think about all that? am i missing some thing?
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