Build a Pneumatically Actuated Yeti in a Cage for a Halloween Haunted House

Picture of Build a Pneumatically Actuated Yeti in a Cage for a Halloween Haunted House
This pneumatically actuated, caged Yeti was part of the 2005 Occidental Haunted House that was the brainchild of Dale Dougherty, editor of Make. A giant pneumatic cylinder makes the monkey puppet appear as though it's trying to break out of the cage. Hidden air lines give onlookers a burst of compressed air in the face as they try to peer into the cage.

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Step 1: Build the cage

Picture of Build the cage
I used wood held together with biscuits and glue. I could have used screws, but I sure do love using my biscuit joiner. My cage is 24 in. wide, 27 in. tall, and 35 in. deep.

Step 2: Make bars

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After drilling holes through the wood, I dropped in scrap dowels and rebar to make bars.

Step 3: Make ceiling and floor

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Cut pieces of plywood to make a ceiling and floor for the cage.

Step 4: Paint the cage black

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I spray painted the cage black.

Step 5: Install pneumatic cylinder and switch

Picture of Install pneumatic cylinder and switch
The pictures are bit out of order because I installed the pneumatics first to test the whole thing out and then removed them to paint.

The 6 inch throw, 3 inch diameter double-acting pneumatic cylinder was a backup from another project that acutally needed such a thing. The valve is a 4-way, 2-position lever-operated control valve (part #4493k34 from McMaster-Carr). Both items are kind of pricey, so since being purchased originally for a consulting project they have been reused in a number of other projects. Compressed air is generated by a portable compressor used to power the air flow on the Squid Labs laser cutter when we take it to conferences or events.

The 4-way, 2-position valve is pretty neat. When you switch the position, it vents one side of the cylinder and pressurizes the other.

Step 6: Install puppet mount

Picture of Install puppet mount
I put a 2x4 on a hinge and tied it with innertubes to the piston. The 2x4 went into the puppet like a hand.

Ward_Nox7 years ago
its a little slow and id use a scarer looking animal
that would scare the crap out of me if it was faster and made a scary noise.
sort of the point isn't it lol
butters87547 years ago
god thats funny. nice instructable, i love it great awesome funny except it was a monkey not a yeti. ;)
benthekahn7 years ago
I actually saw it working cause i live really close to occidental. It was pretty awesome. Was a bit noisy though
oops, you already mentioned those, sorry.
Neat instructable, What would be really scary is if you put leds in the eyes and made it so it would roar really loud.
0.775volts8 years ago
You can also give the puppet an internal skeleton (armature) to hold his arms out. what pressure are you running, ~20psi? with that cylinder diameter you could really make that monkey leap out. also, ebay is a great source for cheap pneumatics, I got a 10 circuit, individually regulated, double action solenoid actuated manifold for $50.00. way bigger than i'll ever need, but it's great for this kind of stuff.
ewilhelm (author)  0.775volts8 years ago
I can't quite remember the pressure, but it was probably around 30 psi. The monkey did move pretty quick, but I was mostly concerned about compressed air at too high a pressure spraying out the front from the hidden airlnes. I aimed for startling, but not dangerous.
hehe :-P

If I can dig up some pistons, I will definitely try to do this. But I don't know if I have them...
(I know I have a compressor, so I should have pistons, right?)
same here
samando8 years ago
you could even cover it completely up with cloth and replace the 'yeti' with something less expensive so the cage just jolts around a bit
zachninme8 years ago
Awesome! I skimmed the instructable, so maybe you can't do this, but I would replace the wire with fishing line, so you can't see it.
ewilhelm (author)  zachninme8 years ago
In low light you couldn't see the wire, so it wasn't a problem.