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Re: [cosmacelf] Gilding Lee's Lily (membership card)

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  • Lee Hart
    ... Maybe; do you have more thumbs than I do? :-) Seriously, I know *my* fine motor skills aren t that good, either. That s why I m trying hard to make it
    Message 1 of 2 , Aug 25, 2005
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      Bill Rowe wrote:
      > ooh, here's an idea! Lee's design goal is to separate the processor
      > & support part of the membership card system from the front panel
      > part with a dip header connection between them and fit the whole
      > into an altoids box.
      >
      > He has seriously overestimated my fine motor skills...

      Maybe; do you have more thumbs than I do? :-) Seriously, I know *my*
      fine motor skills aren't that good, either. That's why I'm trying hard
      to make it buildable without any origami techniques or surface-mount
      soldering.

      The board size is 2.25" x 3.625" = 8.15 sq.in. The computer board has 7
      chips; 1802, RAM, input latch, output latch, address latch, and two
      "glue" chips. These total 1.47 + 1.05 + 1.32 + .64 = 4.48 sq.in. So the
      component density is only 55% (my goal is 50%). A 50% component density
      gives you adequate room for big solder pads and fat fingers between
      parts. :-)

      The front panel board has all the switches, LEDs, resistors, and D
      connector to the PC parallel port. Its density is even less. The
      challenge is to keep the height of both boards under 0.8" (the height of
      the Altoids box). With the subminiature toggle switches and vertical D
      connector, I think I'm there.

      > an alternate "candy box lid" could contain the USB circuitry.

      Yes, that could easily be done. The computer board is really a
      standalone computer; its pin header is just power, ground, input and
      output port bits, Q, and flag lines. These could easily drive a USB
      board.
      --
      "Never doubt that the work of a small group of thoughtful, committed
      citizens can change the world. Indeed, it's the only thing that ever
      has!" -- Margaret Mead
      --
      Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
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