I have wanted a rotary compression tester for ten years.
Without realizing I had one sitting in my hanger
disguised as a Heath Kit strip chart recorder.
The paper runs at selected constant speeds while the
pen responds to 10 volts peak to peak. All I need now is a
30 dollar Free Scale pressure sensor like the one
Tracy uses in his EFI computer. Puts out 0 to 5 volts
from 0 to 30 psi. The paper drive motor is not
working but it looks simple to fix with all that
30 year old tech. The pen servo works great.
I found it when I was looking for the Aussi
CD system.

Paul Lamar