[Creeping Death]

I have built an airless body slinger that is tripped by a string pulled by someone. I'm trying to come up with some way to trip this prop mechanically with some sort of accuator, and a motion sensor or a mat switch or something.
Any ideas, I don't want to have to have an air compressor hooked to the prop, and I like the fast action I get with the mechanical springs as opposed to an air cylinder, I just need some way to trip it without acutally having to hide a person to pull the string everytime. Resitting it manually won't be a problem since I plan on watching everytime it goes off to see my party guests wet themselves.

Any ideas

 

[MikeBru]

What mechanism do you have right now? Pulling a pin? For that you could use a solenoid, like for power door locks in a car wired to your switch of choice.

 

[DaveintheGrave]

Yea, that's what I was thinking. Use a solenoid. Just have the pin of the solenoid cocked inside a piece of PVC pipe attached to the prop. When triggered (by switch mat or whatever) the pin pulls into the solenoid , releasing the prop. Then manually reset it.
I've always wanted to try this, but haven't yet!