This is a simple pressure switch for Technic pneumatics. I would expect that in a real application, this would be in a system with an air holding tank and my Technic Double-Acting Compressor.

The main difficulty I had was getting the arms and the resulting motion just right. The compressor will stay ON for most of the cylinder stroke, turning off just before the end.

I should probably rephrase that previous paragraph. What I mean to say is that once I figured out which parts to put together to get the stroke just right, it worked very well. You should have no adjustment troubles if you use these parts.

In case you are wondering how the power is turned on and off, the Technic Polarity Switch is used. It has the neat property of actually being a FWD-OFF-REV-OFF rotary switch!

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