[sci.electronics] looking for sensor

bud@umiami.miami.edu (06/26/90)

I am looking for a very high-precision tilt sensor.  It must be fairly small

and operate off of low voltage DC or AC.  The Spectron company makes such a

sensor for avionics applications, but $150 is quite expensive.  I would 

appreciate any help on locating another source of such sensors.

Please respond directly.


	Thanks in advance,

   	Bud Pinder
	University of Miami
	

ornitz@newkodak.kodak.com (Barry Ornitz) (06/27/90)

In article <6452.26874295@umiami.miami.edu> bud@umiami.miami.edu writes:
>I am looking for a very high-precision tilt sensor.  It must be fairly small
>and operate off of low voltage DC or AC.  The Spectron company makes such a
>sensor for avionics applications, but $150 is quite expensive.  I would 
>appreciate any help on locating another source of such sensors.
>   	Bud Pinder
>	University of Miami

Unfortunately you have asked for very high precision but consider $150 quite
expensive.  The following companies make tilt or angular displacement sensors.
Your university library certainly should have a Thomas Register where you can
look up addresses and telephone numbers (don't expect cheap, however):
	Aerodyne Controls Corp.
	Honeywell Visitronic
	Humphrey Inc.
	Pace Transducer Co.
	Precision Level Vial Company
	Robinson Halpern
	Schaevitz Engineering
	Sundstrand-Sauer
	Systron Donner, Inertial Div.
	Xecutek
Another approach that is considerably cheaper but far less accurate is that 
taken by Universal Photonix of Laguna Hills, CA.  This utilizes an "electronic"
bubble cell which is essentially an electrolytic sensor.  As the cell is tilted
more of an electrode is immersed on one side of the cell; the electrode on the
opposite side of the cell is immersed less.  A conductive electrolyte is used.
Wiring the sensor into a bridge circuit with an op-amp, you should get an
output voltage propportional to tilt.  There was an article on this sensor in
Automotive Electronics earlier this year you might want to check out.
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larry@kitty.UUCP (Larry Lippman) (06/27/90)

In article <1990Jun26.192024.17036@newkodak.kodak.com>, ornitz@newkodak.kodak.com (Barry Ornitz) writes:
> >I am looking for a very high-precision tilt sensor.  It must be fairly small
> >and operate off of low voltage DC or AC.  The Spectron company makes such a
> >sensor for avionics applications, but $150 is quite expensive.
> ... 
> Another approach that is considerably cheaper but far less accurate is that 
> taken by Universal Photonix, Laguna Hills, CA.  This utilizes an "electronic"
> bubble cell which is essentially an electrolytic sensor.  As cell is tilted
> more of an electrode is immersed on one side of the cell; the electrode on the
> opposite side of the cell is immersed less.  A conductive electrolyte is used.
> Wiring the sensor into a bridge circuit with an op-amp, you should get an
> output voltage propportional to tilt.

	The Spectron sensor is also an electrolytic potentiometer (as above),
with their better models being capable of resolving to seconds of arc (note
that I have not commented about linearity, however).

	An electrolytic potentiometer can be a low-cost means of measuring
inclination.  However, it is important to realize that these devices MUST
be excited by an AC voltage having a waveform with as much symmetry as
possible.  The use of DC may cause internal corrosion of the electrodes
which will have an adverse effect upon performance.  The Spectron data
sheets even go so far as to warn against the use of an ohmmeter for testing
of the device.

Larry Lippman @ Recognition Research Corp.  "Have you hugged your cat today?"
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