This is a little off to the side of the main conversation, but here is the T-shirt launcher we made last summer. It uses a balloon tank with a sprinkler valve and 2 Viair compressors. It has a water separator to keep moisture out of the tank (our last one rusted through the bottom). It also has a analog pressure sensor so I can set the pressure shutoff psi.
It runs off a cRIO-II. We will be putting addressable LEDs on soon.
http://youtu.be/H_IjhJFgQIY