I have an air cannon, but would like to convert it to a machine-gun effect. Anybody have a way to make a homemade repeat timer that will click on/off that fast? I have one that will only go down to 1 per second.

I have several solenoid valves to try as well... just want to mix things up from the big single burst to a different effect.

This is all activated by a hidden pir sensor embedded in a skull.