Page 328 - Robots Androids and Animatrons : 12 Incredible Projects You Can Build

16.9 Insert air foot-pump adapter

soda bottle larger than 1 liter (L). A half-liter bottle is ideal. I’ve tried
the bottle cap adapter on all sizes of PET soda bottles up to 2 L, and
it fits all of them.

Empty the PET bottle of soda and clean it out with tap water. The
bottle should be completely dry before using. It’s interesting to
note that if a full bottle of soda is dropped, the resulting pressure 307
caused by the release of the carbonated soda greatly exceeds the
50-psi limit we impose on the bottle. Soda companies have designed
PET bottles to withstand a rapid increase in bottle pressure, which
would come from dropping the bottle. This is something I never
realized before working with the air muscle, and thought I would
pass it on. Remember, no glass bottles should be used in the air
muscle pneumatic system.

Building the first demo device

The first mechanical device we will build is a simple one that can be
used to measure the contraction of the air muscle (see Fig. 16.10).
The base is 1" 2" lumber and is 11" long. I used this material
simply because I had it lying around. You can just as easily use
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metal or plastic. At each end I drilled a hole to accept a 1 / 4"-long
8-32 machine screw. The machine screws are inserted and held in
place using two 8-32 nuts, one nut on each side of the wood. The
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head of the screw and shaft protrude about / 4" above the wood.
The top screw is threaded through the top opening of the air
muscle, before inserting the screw into the wood. A rubber band
is looped through the bottom opening of the air muscle and then
Team LRN Android hand