T-shirt Launcher

[GeeTwo]

Originally Posted by Sperkowsky

What valve do you recommend.

We're using one that looks just like this (I think it's the same one). We're switching it with a relay module, though a spike would also work. We have two barrels, and one of these on each. We often fire them about a tenth of a second offset from each other; 50ms for each to be open is more than enough.

We currently have all steel, brass, and rubber up to the final nozzle, and PVC barrels. Based on what I've read here, we'll be making some mods before next football season.

BTW, we did not use a 'RIO for our air cannon - an arduino on the robot with an xBee comms module, and a remote with just an xBee module and a 9V battery and some buttons/joysticks to dive, shoot, and someday aim in azimuth. Our accumulator is filled manually from a scuba tank; the accumulator holds enough for about 40 good shots before losing pressure.

[Bertman]

We had the same discussion a few years back and opted to go a different route. We made a giant nerf gun which shoots 1' sections of pool noodles. At top speed it will now shoot a "nerf bullet" about 70' which can then be traded in for a t-shirt or whatever you choose. It also allows for good demonstrations with younger kids and has little chance of injury. The pneumatics only feed each noodle into the spinning wheels which work like a baseball pitching machine.
here is a picture location

http://www.chiefdelphi.com/forums/sh...099#post776099

[Sperkowsky]

Originally Posted by GeeTwo

We're using one that looks just like this (I think it's the same one). We're switching it with a relay module, though a spike would also work. We have two barrels, and one of these on each. We often fire them about a tenth of a second offset from each other; 50ms for each to be open is more than enough.

We currently have all steel, brass, and rubber up to the final nozzle, and PVC barrels. Based on what I've read here, we'll be making some mods before next football season.

BTW, we did not use a 'RIO for our air cannon - an arduino on the robot with an xBee comms module, and a remote with just an xBee module and a 9V battery and some buttons/joysticks to dive, shoot, and someday aim in azimuth. Our accumulator is filled manually from a scuba tank; the accumulator holds enough for about 40 good shots before losing pressure.

Have you had any issues with the pvc barrel. We are in ny which is cold. We would probally use ours most at football and lacrosse games which are both cold.

[GeeTwo]

Originally Posted by Sperkowsky

Have you had any issues with the pvc barrel. We are in ny which is cold. We would probally use ours most at football and lacrosse games which are both cold.

No, but we've only used the current barrels at three games, perhaps 100 cycles per barrel including testing. I'm not going to wait to have a problem to fix an unsafe condition.