Check out our cannon bot!

[Dick Linn]

My 16 year old does the building, I just buy the goodies.

My favorite is a 2 liter soda bottle with a 1/4 to 5/16 inch (or so) hole in the cap. About a 6 to 7 second spritz of propane from a torch, put the cap back on, put it on some sort of guide rail and light it. WHOOSH. It ignites and the exhaust goes sonic, so watch your ears and don't get burned by the hot exhaust. It'll send a bottle quite aways. You have to squeeze the bottle a few times to purge between firings. The bottles start to deform after several launches.

[Rickertsen2]

I always hear people talking about using sprinkler system valves for homemade pneumatic projectile launchers. The valves on my sprinkler system are motor actuated ball valves. They take about 4 seconds to open fully. This seems rather slow. Is this what people are talking about or is there some other tyoe of sprinkler valve? I have built several devices using quick release valves from semi-truck air brake systems and they have worked well.

[ZZII 527]

Some pics and video of one of the meanest Vex bots known to exist:

http://web.mit.edu/scolton/www/tankbot1.jpg
http://web.mit.edu/scolton/www/tankbot2.jpg
http://web.mit.edu/scolton/www/tankbot3.jpg
http://web.mit.edu/scolton/www/tankbot4.jpg
http://web.mit.edu/scolton/www/tankbot_clips_web.wmv
http://web.mit.edu/scolton/www/tank_slow_web.wmv

[greencactus3]

Originally Posted by Rickertsen2

I always hear people talking about using sprinkler system valves for homemade pneumatic projectile launchers. The valves on my sprinkler system are motor actuated ball valves. They take about 4 seconds to open fully. This seems rather slow. Is this what people are talking about or is there some other tyoe of sprinkler valve? I have built several devices using quick release valves from semi-truck air brake systems and they have worked well.

there are solenoid ones. which would mean they are fast.... but apperently according to a link someone else posted before, those solenoids still arent fast enough. im planning to get a standard solenoid one soon. see what i can make outta it. i have some big plans for next spring.

[Dick Linn]

Check here: http://www1.iwvisp.com/thehalls/ggdt/

For a sprinkler system, I'd imagine a motor-actuated ball valve is better. You don't want to open or shut a sprinkler (hydraulic) system quickly. But a cheap valve may be better suited to pneumatic operation, especially as modified. I think these valves are about $16., last I remember.

[Doug G]

Originally Posted by greencactus3

there are solenoid ones. which would mean they are fast.... but apperently according to a link someone else posted before, those solenoids still arent fast enough. im planning to get a standard solenoid one soon. see what i can make outta it. i have some big plans for next spring.

We just used a standard off the shelf sprinkler valve that has a diaghram and is actuated by a knob manually or by a solenoid. The solenoids are supposed to operate at 24 VAC. But after some experimentation we found a single spike relay connected to just 12-13 VDC on the robot works fine. At first we thought we were going to have to configure an additional power supply, but in the end we didn't Now to rig up a motor to a compresser to charge our two large tanks - hmmm, might need a deep cycle marine battery as well.

I heard about Elk Grove's (1147) T-Shirt Launching robot at the Kings game - if you do it again let us know (not ride your coat-tails, but to promote robotics of course) we'd be happy to join you out there.

[billbo911]

Originally Posted by Doug G

I heard about Elk Grove's (1147) T-Shirt Launching robot at the Kings game - if you do it again let us know (not ride your coat-tails, but to promote robotics of course) we'd be happy to join you out there.

The request for future performances has already been placed! We now wait with baited breath. If we do get an invitation to do it again, we will most certainly request that you join us. Promoting FIRST Robotics is way more important than promoting just our team! Besides, a little competition on the court is way more fun, and better exposure, than performing solo.

BTW, did you follow the link and see the short video I posted a few frames back? You should have seen the smiles on these kids faces after they came off the court! <--- That's what they all looked like.
In fact, here is a link to a picture I snapped as they were exiting the court. It doesn't even do justice to what we saw once they got off the court and thought about what they had just done.