The T-Shirt Cannon Broadside (Part I)
Technically this is old news as it happened back in August, but I never got a chance to write a dev log about it so I thought I talk about it here instead. If you happened to go to the Penny Arcade Expo this year and check out the exhibit hall you might have seen our booth for Pirates of the Burning Sea complete with T-Shirt Cannon broadside, which we used to fire t-shirts into the crowds every hour (unfortunately you can only see the shirts for like 3 frames in the youtube video). Actually making the t-shirt broadside a reality proved to be a much more complex project than I had originally planned for.
It all started back in early July. Theresa, one of our community managers was planning our booth for PAX. When she mentioned that we would be giving away a ton of shirts we got to talking about fun ways to go about handing them out to fans. It occurred to me that a pneumatic t-shirt launcher would be a memorable distribution mechanism. I'd built my fair share of pneumatic potato cannons back in my more mischievous high school days and I had a proven low power design in mind based around a RainBird Automatic Sprinkler Valve. Basically you have one sealed 2" x 3' section of PVC pipe connected to one end of the valve that you fill with compressed air and a open 2" x 3' section of PVC pipe connected to the other end that's used as the barrel. Load a shirt in, pressurize, and then open the valve (either electrically with a battery pack or manually with the quick release switch).
One quick trip to Home Depot, an evening spent cutting and gluing and voila I had the first model complete. The initial design had a few flaws though. The first problem was that I had the pressure gague and valve right on the end of the air chamber next to the end of the barrel (scary!). The other problem was that I was lazy and didn't use anywhere near enough epoxy on the joints. I was reminded how important proper gluing was when we were doing our first test firing behind the office. We had a few successful shots at 45 PSI and I got cocky. "Let's juicy it to 90PSI!"I said, drunk with pride at a prior successful firings. We charged the cannon up to 90 PSI, I picked up the cannon by the barrel standing along side it, then PFFSSTT-CRACK-SMASH! The entire valve on the back end of the cannon sheered off, rocketed away, and smashed into cement wall 8 feet away. Fortunately no one was hurt, but I was reminded how scary high pressure air can be and how important proper gluing and safety considerations are.
Despite the set back everyone was excited about the t-shirt cannon. During our daily afternoon coffee run to El Diablo we all started spinning ideas about how we could spiff up the cannons. What started as a plan for a simple hand-held device grew into a decorated 3-cannon broadside.
That weekend I whipped up three new air cannons with a better air system design. I wanted to keep the valves and pressure gauges away from the cannon on the end of a hose that's permenantly attached to the side of the cannon. That way if there was a failure the worst thing that could happen was a hose popping off rather than sending a gauge off into the audience. I also found a really cheap, portable air compressor that was small enough to hide under a table at the booth and was pretty quiet too. Once I had the air cannon portion of the project done the next step was decorating them too actually look like real cannons. Since this blog entry is getting long enough and it's getting late I'll save that for a part 2. More to come soon!
It all started back in early July. Theresa, one of our community managers was planning our booth for PAX. When she mentioned that we would be giving away a ton of shirts we got to talking about fun ways to go about handing them out to fans. It occurred to me that a pneumatic t-shirt launcher would be a memorable distribution mechanism. I'd built my fair share of pneumatic potato cannons back in my more mischievous high school days and I had a proven low power design in mind based around a RainBird Automatic Sprinkler Valve. Basically you have one sealed 2" x 3' section of PVC pipe connected to one end of the valve that you fill with compressed air and a open 2" x 3' section of PVC pipe connected to the other end that's used as the barrel. Load a shirt in, pressurize, and then open the valve (either electrically with a battery pack or manually with the quick release switch).
One quick trip to Home Depot, an evening spent cutting and gluing and voila I had the first model complete. The initial design had a few flaws though. The first problem was that I had the pressure gague and valve right on the end of the air chamber next to the end of the barrel (scary!). The other problem was that I was lazy and didn't use anywhere near enough epoxy on the joints. I was reminded how important proper gluing was when we were doing our first test firing behind the office. We had a few successful shots at 45 PSI and I got cocky. "Let's juicy it to 90PSI!"I said, drunk with pride at a prior successful firings. We charged the cannon up to 90 PSI, I picked up the cannon by the barrel standing along side it, then PFFSSTT-CRACK-SMASH! The entire valve on the back end of the cannon sheered off, rocketed away, and smashed into cement wall 8 feet away. Fortunately no one was hurt, but I was reminded how scary high pressure air can be and how important proper gluing and safety considerations are.
Despite the set back everyone was excited about the t-shirt cannon. During our daily afternoon coffee run to El Diablo we all started spinning ideas about how we could spiff up the cannons. What started as a plan for a simple hand-held device grew into a decorated 3-cannon broadside.
That weekend I whipped up three new air cannons with a better air system design. I wanted to keep the valves and pressure gauges away from the cannon on the end of a hose that's permenantly attached to the side of the cannon. That way if there was a failure the worst thing that could happen was a hose popping off rather than sending a gauge off into the audience. I also found a really cheap, portable air compressor that was small enough to hide under a table at the booth and was pretty quiet too. Once I had the air cannon portion of the project done the next step was decorating them too actually look like real cannons. Since this blog entry is getting long enough and it's getting late I'll save that for a part 2. More to come soon!
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Very exciting stuff. Glad to see you are blogging. I haven't done it in far too long... I should really get back into the swing of things.
One quick thing, you're youtube link is busted... I think you forgot to put a colon before the double slashes. It's hard to be 100% certain since I don't know the software. Anyway, you should take a look.
Keep it up and I'll keep reading.