Wow, been a while since I've been on here.

I am working on a video project, and I need to build a backpack guacamole gun of sorts for it.

An example can be seen here:

<iframe width="425" height="349" src="http://www.youtube.com/embed/qYTgE-dR_ZA" frameborder="0" allowfullscreen></iframe>


If the video doesn't work here, here's a link: http://youtu.be/qYTgE-dR_ZA

At 0:45 there is an example of what I'd like to accomplish. But not quite sure how to go about it.

I figure I can use a compressed air canister from a paintball gun, and there are places to buy those as well as parts and fittings, but I don't really know anything about solenoids, etc. It would be great to have it all self-contained so I wouldn't have to have power wires running along the ground and up a pant leg. Is there any sort of solenoid (or similar item) that can run on battery power that will allow for a quick release of gas/air to achieve this effect?

Thank you in advance.