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Re: stopping the wearable from "crashing" whe battery's run out ??

From: "D. Firestone" <>
Date: Fri, 27 Mar 1998 22:38:26 -0800

Omar Jenkins wrote:
> 
> I have been working an electronics project which involves alot of analog
> voltage measurements.  One of the easiest and cheapest ways would be to
> attach 3 or 4 potentiometers to the battery and 3 or 4 comparators.  The
> potentiometers would be set to various power settings.  one for
> 90%, one for 50%, one for 10%, and one for 5%.  When the voltage is above
> the potentiometer, the comparator outputs high(~5volts), and if the
> voltage is below, the comparator outputs low(~0volts).  This way, all four
> would be high if the capacity is above 90%, the last three on if the
> capacity is above 50%, the last two if the capacity is above 10%, and the
> last one if the capacity is above 5%.  These for would be wired ot the
> parralel port or something of the wearable, and Linux could tell you what
> the current power situation is, and if it drops below 5%, the system would
> begin to shut down automatically unless you over rode it.
> 
> On Fri, 27 Mar 1998, Neill Newman wrote:
> 
> > I have a question for all those currently running linux or win95 (or any
> > OS which behaves the same as described below) on their wearables.
> >
> > under linux, if the machine is turned off whilst running, the disk is
> > not unmounted properly and an fsck is performed next time the machine is
> > powered up, a similar thing happens under win95, a drivescan is
> > performed when rebooted.
> >
> > Since this is unadvisable because of possible data coruption/loss, how
> > do the wearables out there detect that the battery's are running low in
> > order to warn the user and shut down the machine safely ??
> >
> > presumably their needs to be some kind of battery life detection circuit
> > which can be interfaced to the machine to warn the OS ??
> >
> > thoughts ??
> >
> > Neill
> >
> >
> > --
> > 

Forgive me...I'm going back a few years...but wouldn't potentiometers
and comparators be measuring preset "potential"  i.e. voltage rather
than power?  Then there are two other considerations.  Unless, the
comparators were driven by separate batteries their usefulness would
drop off as the battery's voltage drops off.  And I would expect the
computer to shut down long before 50%, 10% or 5% were ever reached....

Just a thought....

Dave

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