[simpits-tech] Pneumatic controllers

[Matt Bailey]

On Saturday 26 February 2005 01:11, Bubba wrote:
> Matt Bailey wrote:
> > This is indeed something I quickly realized when considering using a
> > servo to
> > control a valve, or to control the altimeter needles
> > directly........the
> > servo just isn't precise enough. I think the bottleneck in that case
> > would be
> > the mechanics of the servo. As precise as R/C servos are, they're
> > still
> > designed for ~90* of rotation, not adjusting a valve precisely within
> > a few
> > hundreths of a PSI, or rotating an altimeter arm 7,000* precisely.
>
> Ditch the RC servos and go with industrial stuff. There are some out there
> that have resolutions so tight you can't see the output shaft move. Like
> .001 degree. Steppers would work too, but you have to give 'em a home
> switch somehow.

	Bah, I can make adjustments to the servo position where I just hear the motor 
move, without the output shaft visibly moving. What kind of cheapo servos 
were *you* using? ;)
	In all seriousness...........the industrial servos are attractive, with the 
ability of some to move a LOT more than 180* (I saw mention somwhere of 
servos that feature continuous movement.....THAT would be cool). I'd probably 
be all over them if I could afford them........but aren't they rather pricey?
	The R/C stuff should be fine for instruments with less than 360* of motion, 
but industrial rigs would be a welcome addition if you can point me to one of 
the following:

1. A dirt cheap source for the servos

2. A huge amount of cash and/or a way to make a huge amount of cash :)

	-Matt Bailey