This instructable will show you how to build a Pneumatic cannon utilizing a modified sprinkler valve. Yes, I know that this has been done before, and there are a few other good instructables on this subject, but what sets this one apart is the valve modification. I have noticed on other instructables they merely tell you to "go to spudfiles and figure it out yourself." This took quite a bit of research on my part to figure out exactly how to do this correctly. Therefore, the main focus of this instructable will be the modification of the sprinkler valve. also, there will be no image notes until the bug gets fixed, sorry.