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Subject: RE: Rockbox for the player
From: Stuart Tedford (stuart.tedford_at_piresearch.co.uk)
Date: 2002-09-12


> The battery voltage will drop considerably
> (compared to the
> idle voltage) when the drive is spinning up due to the extra
> current draw
> and the internal impedance of the batteries.

Why don't we simply do away with all this "is the hdd spinning" bollox by
using a recusive filter on vBat.

Like for example a 90% filter:

filteredVbat = vBat - ((vBat - filteredVbat ) * 90) / 100;

where filteredVbat is declared static and vBat is the instantaineous battery
voltage.

Only thing is that it needs to be called at a constant rate but wouldn't
that be better than storing loads of instantaneous values and doing averages
etc?

Stu.



Page was last modified "Jan 10 2012" The Rockbox Crew
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