Re: [CAD_CAM_EDM_DRO] 5V+ Supply for Gecko?

In a message dated 9/22/2004 5:16:13 AM Central Standard Time,
cnc@... writes:
can I get away with using the 5V power
supply in my servo-box, and getting 5V from the parallel port,
without needing to run an extra wire from the PC?
Abby: Surely much wiser sages "in here" will respond with more wisdom on
this point, but I can tell you this: The Parallel Port has ONLY "ground" and NO
source of +5VDC. Sad, yes. However, if you have any of those USB ports, or
an unused game-socket or the like, OR, if you are not afraid to "tear into" the
PC, and find an unused "drive supply plug" (the white plastic things with
four wires, usually two black, a red, and a yellow or orange), the "red un" is
5VDC. For one of my widgits, I got some "surplus" USB cables and cut off a
useful length, plugged in the "good end" and used a DVM to "find +" out the "cut
end". Neat. But don't expect to be able to light up Manhattan with the
current off of that! I'd guess 100 mA is about the limit. It is nice to have the
5VDC supplied from the computer, so the logic signals from the parallel port
are "same source" and all that. No "surprises". Go dickin' with different DC
sources, and you WILL one day end up with "opposite polarities in series" or
the like, and let out some expensive magic smoke! BE careful! If you don't
electrocute yourself first, you WILL do heinous and untoward damage to some
FINE expensive silicon! Jan Rowland


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