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

[Matt Bailey]

Excellent idea! Actuating the bellows is sorta what I was thinking early
but I wasn't sure if it would allow enough precision (I was thinking of
gearing the servo or something). What is the altitude range on your
altimeter?

	-Matt Bailey

Craig Rochester wrote:
> 
> I've used a servo with a cam to get very precise position output.  Here's
> the concept:
> 
> In practical application I epoxy the servo's splined hub off center in a
> bearing.   Over 180 deg rotation the deflection is the distance from the
> rotation axis and the bearing center.  It works well for the 1/8" travel to
> operate a pressure regulator:
> 
> IIUC, the altimeter work on the expansion of a sealed bellows as the
> atmospheric pressure decreases.  The bellows must drive some precision gear
> system.  Maybe the servo could do the work.
> 
> Craig R.