From: Stuart Tedford <stuart.tedford_at_piresearch.co.uk>
Date: Thu, 12 Sep 2002 14:22:35 +0100

> 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.
Received on 2002-09-12