Subject:
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Re: Battery Status
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Tue, 4 May 1999 00:48:16 GMT
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Original-From:
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Richard Drushel <drushel@apk(NoSpam).net>
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Viewed:
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897 times
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[Duncan Orthner] spake unto the ether:
> At 01:40 PM 5/3/99 -0700, Andre Philippi wrote:
> > 2) Could I use one of the analog ports on the Handy Board to measure battery
> > voltage (and therefore calculate capacity left (assuming voltage is
> > information enough for the calculation)) ?
>
> Yes. You could use a voltage divider. You may have to play with the cutoff
> point a bit, and be aware that nicads experience a rather sharp voltage drop.
But isn't the supply voltage also the reference for the D/A
converter? If the reference drifts, the signal through the divider
leg will also drift? I remember trying something like this with a
variety of fixed resistors in an analog port, and had the board dump
values every second out the serial port to a terminal capture until
the batteries died. IIRC, the analog() values were constant until a
couple seconds before power failure, and then they fell only 1 or 2
units out of 256.
*Rich*
--
Richard F. Drushel, Ph.D. | "Aplysia californica" is your taxonomic
Department of Biology, Slug Division | nomenclature. / A slug, by any other
Case Western Reserve University | name, is still a slug by nature.
Cleveland, Ohio 44106-7080 U.S.A. | -- apologies to Data, "Ode to Spot"
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Message is in Reply To:
 | | Re: Battery Status
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| (...) This is usually how it's done. The voltage will drop predictably as the battery discharges. (...) Yes. You could use a voltage divider. You may have to play with the cutoff point a bit, and be aware that nicads experience a rather sharp (...) (25 years ago, 3-May-99, to lugnet.robotics.handyboard)
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