This valve is based heavily on
Linc's Pneumatic Switch. It has been modified to remove some friction
on the worm gear, and to hold the 24t gear a little more firmly. Most
importantly, it adds a touch sensor at the center of the valve arm's throw,
so that the controlling program can keep track of its position.
The resulting structure is about one stud thicker than Linc's design.
More photos of the valve:
Building instructions for the valve are available
as a series of 15 images in three parts.
Copyright © 1999 Ben Williamson