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[DPRG] Pressure sensors (was: Accelerometer Questions)

Subject: [DPRG] Pressure sensors (was: Accelerometer Questions)
From: John Caldwell jcaldwel at jcpenney.com
Date: Thu Nov 21 08:44:01 CST 2002

Here's a $1.00 pressure sensor:

Take an empty, 1 liter plastic Coke bottle.
Drill 2 1/4" holes in the bottom; run a string in one hole and out the
other; tie it in a big loop.
Unscrew the top, stick a red baloon in it and blow it up until the bottle is
just filled.
Take some white adhesive tape, mark it in 1" steps, and stick it up the side
of the bottle.
Take the bottle diving and hold it by the loop
The air will be compressed as you dive and more of the bottle will be filled
with water
Remember the mark where the air/water boundary is at 30', 60', etc.
When you come up, mark the feet on the 1" tape.
Change the balloon from time to time.

John Caldwell
Secretary DPRG.org

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