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Psychomaniac
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623 Posts
Discussion Starter #1 (Edited)
Leg blaster air cannon project

I just completed my leg blaster air cannon...



I just need to paint it tomorrow and the pneumatic portion is done. It's a combination of metal pipe (for the pressure side) and PVC (outlet side).

I had a hard time finding a sprinkler valve that would work without honking. I ended up with a Lawn Genie (by Toro) 1" jar top anti-siphon. I wanted an inline valve but none would do the trick without unwanted noise. This valve doesn't honk at all. The 180 degree valve style turned out to be a help when I configured the cannon to get the barrel off the ground. This configuration also stabilizes the cannon when firing (it produces quite a kick, even with a 1" barrel). It won't be on the vice when it's in place under the bushes. I'm running it at 80 PSI and the sound is very good and the air blast is even better.

I already have my 120v motion sensor (hacked from a security light). I have a 120v interval timer relay on the way that will open the valve for 1/10 of a second when AC power is applied. Then it shuts down and waits to be tripped again. I have the motion sensor set for ten seconds so the cannon won't fire too often and ruin the effect. I'm putting a snoot on the motion sensor head so it triggers only when someone is right in front of the barrel.

I think this is going to really scare people this year. No one expects it and it's quite an event when it goes off!

I'll post the electrical detail pictues when it's all done.
 

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Psychomaniac
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623 Posts
Discussion Starter #2
I figured I might as well post my other 2008 pneumatic project as well. I wanted to play around with some pop-up sprinklers and see what they could be used for. I bought a 12" model and an extra Orbit 1" jar top valve...



This runs at 40 PSI and will go behind the garage door. When I trigger it remotely it bangs the metal roll up garage door VERY loudly (it'll have a block of wood attached to the end of the sprinkler when it's ready for use). I'm going to have a scene outside that people will view with the garage next to them. I'll be hidden among the prop dummies in an identical outfit. When the get close I'll trigger the bang. I expect everyone will look that way which will give me time to jump up and really put the scare on.

I think I'm going to have to change the configuration to support the same Lawn Genie valve that I used in the air cannon. The sprinkler is making unwanted noises with this valve. I'm going to fire it with an AC wireless remote and I'll probably use another interval relay so it shuts off right after the bang.

I have a bunch of 12v air solenoids around the house and I may use them in this project. I can close off the sprinkler head and use the solenoid to vent the system after it fires (using the same relay). That might quiet it down and also opens some other project possibilities for pop-up sprinklers. I'm amazed how well they work and how fast they deploy! Not bad for $12 each.

More to follow as it's developed!
 

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Hey, did you ever get the electrical part done? I would be very interested to see what kind of timer you used and how you hooked it up.
 

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OpenTrackRacer
Great prop.
I was planning on doing sort of the same thing but behind a fake window with curtains and a zombie behind it.
I may do this instead.
Nice startle scare when you least expect it!
 

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cool thats how you shutup the back feed.... you use a siphon valve, i made a canon too and had that same air feed back sound, i thought the spring was to weak to snap shut so i bought brass valves.......... il save money next time with a siphin valve nice post
 

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Psychomaniac
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623 Posts
Discussion Starter #9
Sorry for being absent for so long. I wasn't getting notifications anymore. The air cannon worked perfectly two years in a row and I don't expect that change. It's pretty simple and robust, especially considering that it'll fire less than 100 times per year or so.

I never did get around to making an electrical diagram, sorry. If anyone has any specific questions about how it's rigged just let me know.
 
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