[simpits-tech] Zero point on a two needle altimeter

[Matt Bailey]

Hmmm true...you'd need to modify the gearing if you wanted to use more
than one hand.

	-Matt Bailey

Rod Dale wrote:
> 
> The minute hand would be okay but the hour hand has 12 positions. An
> altimeter has 10.
> Rod
> 
> ----- Original Message -----
> From: Gene Buckle <geneb@deltasoft.com>
> To: <simpits-tech@simpits.org>
> Sent: Saturday, October 26, 2002 3:03 PM
> Subject: Re: [simpits-tech] Zero point on a two needle altimeter
> 
> > You guys are missing the obvious.  Buy a cheap battery powered clock drive
> > and drop the original motor out of it and drive it with a stepper motor.
> >
> > g.
> >
> >
> > On Sat, 26 Oct 2002, Matt Bailey wrote:
> >
> > > Interesting ideas on this subject! One thing to keep in mind, the
> > > relationship of the turning of the hands of an altimeter is always the
> > > same, the hundreds needle always makes 10 revolutions per one revolution
> > > of the thousands needle etc. So you really only need one connection to
> > > the motor and sensor (perhaps on the hundreds needle, for precision) and
> > > just drive the other needles off that, using gears or pulleys. Also, if
> > > you had a way to measure the position of the ten thousands needle, your
> > > software would always know where that needle was and hence where the
> > > other needles are...only problem might be resolution since there is so
> > > much difference between this needle and the hundreds needle, for
> > > instance. But without having to count the number of revolutions for this
> > > needle, you would get a range of 100,000 feet. Quite sufficient for
> > > anything other than very high performance fighters (like the F-104) or
> > > spacecraft.
> > >
> > > -Matt Bailey