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Hi All,

Here's what I've got on the altitude sensor.  I've found one that is a
pressure sensor that goes off at 4.7 psi. This is the pressure difference
between sea level and 10000 feet.  When hooked to a "sea level" pressure
reservoir the switch is activated when the reservoir exceeds ambient
pressure by 4.7 psi.  I took this up to altitude in a friend's RV6 and it
actually switched at 10,300 ft.  Switching off occurred at approx. 8500 ft.
This is totally acceptable for my purposes of turning on/off a warning
light.  I'll have two in my plane: one for fuel pump reminder mounted in the
gear box area, and one for cabin altitude warning mounted somewhere behind
the panel.  This will warn of cabin altitudes higher than 10,000 ft.
alerting me of potential problem with pressurization system.

The price of the switch is $30 including shipping.  I can also assemble the
reservoir assembly for an additional $5.00.  The reservoir is a couple of
PVC and brass fittings.

The switch is a SPDT.

Let me know if you're interested at woodruff@swefco.com. We'll need to order
20 as a minimum.  I currently have promises on 9 switches - only 11 to go.
I'll do this like I did the foam last summer by buying the lot and then
sending it out to all.

Contact me for a picture of the switch with the reservoir attached.

Hal Woodruff

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Please send your photos and drawings to marvkaye@olsusa.com.
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