Zombie Apocalypse Quarantine Compound

We've had some great themed Halloween parties over the years, and we decided that 2015 was the Year of the Zombie Apocalypse. We've put together a single Instructable showing the entire "Research Facility and Quarantine Compound" :), which contains six animated decorations and many more static ones. We've broken each of the animated decorations down into several steps, but we really wanted to group them all together ... so it is a tad long. But hey, it takes a lot of preparation to survive a zombie apocalypse!

We've worked pretty much non-stop on this since mid-August, but had to keep it in "Stealth" mode, off of Instructables and social media, so as to not spoil the surprise for our victims (er, ahem, guests!) Please enjoy viewing the props as much as we enjoyed creating them!!

The majority of things here can be done by avid DIY'ers, but some of it is “DIY on steroids” :), as our host owns a business with several pieces of heavy equipment, welders, etc. . We used his forklifts and 18-wheeler flatbeds to pick up large gnarly looking things to lend the “compound entrance” the proper level of apocalyptic-ness: old wrecked cars and trucks, tangled knots of broken up concrete and rebar, rusty barrels, old bridges, etc. Several times I found myself chuckling, “doesn’t everybody get ready for their Halloween party this way?” :)

We’ve listed the major materials we used for each prop, but usually don’t get down to the detail of specific measurements. We know that’s a great feature of a good Instructable, but in our case we often just don’t have the info: we started with sketches on some of the designs, but each wound up being modified, and we used substantial amounts of eyeballing, thumb in the wind, and other scientiferous measurement techniques as we evolved the designs. We apologize for not having that level of detail, and hope the rest of the how-to and the lessons learned will still be helpful to others who embark on something as crazy as this!

Here are the major elements of this Instructable:

1. Compound Entrance (animated):

2. Vicious Dog (animated):

3. Zombie in a Box (animated):

4. Chain Saw in the Guest Bathroom Shower (animated):

5. Monster Anaconda Snake Head (animated):

6. Monster Anaconda Snake Tail (animated):

7. Soylent Green Hors D'ouevres Serving (and Preparation?) Machine (semi-animated):

8. Apocalypse Survival Command Center (static):

9. Carving Station (static):

10. Thunderdome (static):

11. Spittoon Lagoon and SS Minnow (static):

Step 1: ​Mixing of Two Themes: Zombies and Gilligan’s Island.

... How does THAT happen??

Somehow early in the party planning process, we merged two wildly different themes: the gruesomeness of zombies, and the happy go lucky nature of Gilligan's Island. Over several discussions, the Gilligan's Island sub-theme emerged. We decided that Skipper and Gilligan were really nefarious toxic chemical dumpers, and those chemicals, some of which were radioactive, turned "Spittoon Lagoon" on the deserted isle into a glowing, bubbling, slimy mess from which arose mutations such as the monster anaconda snake, vicious dog, zombies, and a virus that rapidly spread the mutations. This radioactiveness is of course the link to zombies, arising from the suggestion in the original zombie classic, George Romero's (link) 1968 Night of the Living Dead (link), that zombies were created by radiation. We depart slightly from Romero by hypothesizing that the radiation came not from a space probe returning from Venus, but from good ol' Gilligan right here on Earth.

In the header for this Step, we've posted the video made by Gary and Lynn’s son Kevin, a hilarious explanation of how all these crazy elements are logically (???) tied together, and a tri-fold brochure that we handed out to party guests. The latter, of course, begs the question: if you have to hand out brochures so your guests will understand the party, have you gone just a little bit overboard?? Yes indeedy.

In some of the guest pictures, you'll see photos of the entire Gilligan's Island zombie crew. :)

Step 2: Video Clips of Animated Props

Step 3: Pro Tips, Aka Lessons Learned.

We had a blast designing and building all these things, but as you might expect we stubbed our toes along the way. Here are several of the key lessons we learned throughout the process.

Choice of igniters:

We started with pilot lights, which blew out quickly since our applications are outdoors in windy situations. We replaced these with electric resistance igniters, which were OK but slow. The fastest one we found advertises heating to 1200 degrees C in 6 seconds. In our experience it was close, but took about 8 seconds instead of 6. Neither sounds like a huge deal, but when you want your prop to start belching flame and smoke right away, every second feels like an eternity. We also tried an igniter we had on hand from a gas-fired clothes dryer, but that one took almost 20 seconds to get hot enough to light the propane, which was completely intolerable. So the next thing we would try is a spark-based igniter such as those used on barbecue grills or gas stovetops.

Friction, Friction, Friction:

It goes without saying that you need to minimize friction, and yet we still struggled with it. We leaned toward “low cost” in our early concepts, seeking to use ABS plastic for many of our linkages. In some arrangements, the friction was indeed low, but rigidity was also low – too low to be effective. Do everything you can to minimize friction from the beginning.

Choice of actuator:

In some cases, we solved our problems with quality ball joint linkages. In others, we found that we need to get away from the idea of converting rotary motion (motors) to linear altogether, and go with linear actuators or pneumatic cylinders.

Speed vs. power for linear actuators:
When we shifted from motors to linear actuators for the chain saw and the snake head, we found that they definitely provided the power we needed, but we paid a penalty in slooo.ooo.oooo.www operation. The snake head took fully 20 seconds for its 45 degrees of rotation. We understand that slow can mean dramatic, but we would have liked it to move faster. It turns out that when you’re working within a power budget constrained by 12VDC / 10A power supply, you can have either speed or power, but not both. The linear actuator we used offered ½ inch per second with 225 pounds of force. There are others on the market that allow faster operation but with less force, ranging up to about 6 inches per second (12 times as fast) but only 20-30 pounds of force (1/12th as much). Consider what you’re going to need as you choose your actuators. What if you need to have speed and power, but for short durations? This question drove us away from electrically-powered actuators (think of the tortoise, slow and steady winning the race) to pneumatics (yay, rabbit) for the Vicious Dog. We needed a near-instantaneous scare action, and it required a fair bit of force. Pneumatics allowed us to take advantage of a reservoir of stored potential energy, which could be released quickly. The storage reservoir was replenished after each “shot,” with the compressor charging up a tank of stored energy.

Make it fire proof:

What a great section title! Did that get anyone else’s attention??!  Yes indeed, we managed to set our star prop, the anaconda snake head, on fire. We burned a basketball-sized hole in the side of its head. Fortunately, there was a lot more material to spare. So we filled in the hole with fiberglass, and covered it with expanded metal lath and then cement. The next night, it worked like a champ.

Consider degrees of freedom and range of motion carefully.

We designed the snake head to rotate about 45 degrees, and during the rotation to rise about 5 inches. The rotation would have been very low stress on its own; but by adding the elevation change, we dramatically increased the force on our actuator. And as it turned out, in the snake head scenario, the elevation change was almost unnoticeable, and was greatly overshadowed by the rotation, which gave a sense of ominous portent. So we paid a high price in complexity for a low benefit in prop awesomeness.

Step 4: ​Logic Controller Overview Discussion

As we were searching the web for logic controllers early in the planning process, we found the FrightProps website. Their selection was large and comprehensive, and their explanatory videos were very well done, making the use of the controllers clear. So we ordered all our controllers, as well as many of our actuators and triggers, from them. In retrospect, we would definitely still use FrightProps, but we would choose different controllers for many of our props. This Step explains a little about the controllers for the lay person, and why we would choose differently.

We ordered a big batch early on (see FrightPropsParts-Inventory-0929151333a.jpg for a photo of our "Christmas Arrived Early" unpacking spree), and then a couple of smaller orders as things evolved. In total, we wound up with the following:

• PicoBoo AC - 5: Compound Entrance, Vicious Dog, Zombie in a Box, Chain Saw, and Snake Tail.
• PicoBoo Plus – 1: Snake Head
• PicoVolt – 1: Chain Saw (paired with a PicoBoo AC for that prop)
• PicoBoo – 1: Spare

We've placed the Operating Manuals for each of these controller types in the image section above. There's also a PDF names ZombieProps-2015-WiringDiagrams.pdf, which shows the details of how each prop is wired. (The individual diagrams are broken out in the Step describing each prop, but this has all six in one place.)

FrightProps has a nice chart on the site comparing the features of their controller lineup.

AC vs DC:

First and foremost, we would use the regular PicoBoo (DC relay outputs) for almost all our props, instead of the PicoBoo AC. The reason: we were thinking of these as power SUPPLIES, which is the wrong way to think of them. It’s much better to think of them as power SWITCHES. To many DIY’ers and electrical folks, this is probably pretty obvious. But we missed that important distinction at the beginning. As a result, we spent a little more than we could have otherwise, and wound up with more parts than we needed, because we had to use several AC-DC power supplies.

The PicoBoo Quick-Start Guide and Operating Manual each have good diagrams of how to wire different loads. The most important two for our understanding is excerpted above; see Controlling120VLoads-FP-FromPicoBooManual.jpg and Controlling120VLoads-FP-FromPicoBooQSGuide.jpg. These show how simple it is to use the output relays to turn on and off current flowing through an extension cord to the load. We used this approach on the snake head for controlling the propane and water solenoid valves; you can make it out in one of the photos in that section.

Reversing:

Another reason to use the PicoBoo or PicoBoo Plus rather than the PicoBoo AC is that you can easily wire them to drive your DC actuator in both forward and reverse. This is shown in ForwardAndReverse-FromPicoBooQSGuide.jpg above. Even though this was right in front of us in the Quick Start Guide, it took us a while to find it :).

Bottom Line:

The bottom line out of all this is that our choices of controller worked fine, but we could have had simpler designs by using the PicoBoo line more smartly, as FrightProps intended.

Step 5: Zombie Apocalypse Quarantine Compound Entrance - Overview.

The entrance to our zombie quarantine compound is designed as a chaotic crash scene one might walk through in a post-apocalyptic zombie world. We wanted crashed cars, smoke and flame, water spraying, tangled messes of concrete and rebar, etc, etc, etc. Since our host, Gary, is co-owner of a precast concrete manufacturing plant, we had a rich selection of scrap pieces to choose from and be inspired by. We also had the afore-mentioned 18-wheeler flatbed trailers, forklifts, and more for hauling and placing everything.

We also contacted local businesses, dump sites, and friends to borrow items. Several large gnarly crates came from a business down the road that receives supplies in them and can’t reuse, but leaves them out “free to a good home.” A car dealer loaned us two wrecked cars, and a nearby landscaping business loaned us a wrecked truck and some old beat up telephone poles. From the concrete plant we brought many barrels, a few of them old and rusty; some large plastic chemical totes (NON-radioactive  ) in skeletal-looking frames; a huge mess of tangled rebar and concrete; and a bunch of discarded computer equipment, old fax machines, etc, that we used for the “command post.” You get the picture.

*Tip: Make sure to get pink slips for any cars you pick up from people, otherwise you may not be able to take it to the scrap yard afterwards.

Step 6: Compound Entrance - Materials

Here's the list of materials we used. As with all the parts of this, many of these are what we had on hand, and substitutes would work fine.

• An old shattered pipe to use as a "broken gas main"
• Propane nozzle for the end of the broken gas main
• Propane gas hose, 25 feet
• Solenoid to control the gas
• Electric propane Igniter capable of reaching 1200 degrees C in 6 seconds
• Propane pressure regulator
• Propane tank (BBQ style)
• Another pipe to use as a "broken water main"
• Water nozzle for the end of the broken water main
• Garden hose, 50 feet
• Solenoid to control the water
• FrightProps Electric flash-cracker
• FrightProps PicoBoo AC Controller
• FrightProps Passive InfraRed Sensor (PIR)
• Sprinkler wire (18-5) for connecting the beam sensor trigger to the PicoBoo AC (the sprinkler wire was relatively inexpensive, and the colors of the 5 conductors were a close match for the colors of the beam sensor wires)
• 14 gauge primary electrical wire
• Electrical quick disconnect connectors
• Large external powered audio speaker, and mini stereo cable
• Zip ties for organizing cables and mounting parts
• Lots of large items for setting the apocalyptic tone: junked cars, old k-rails graffiti’d up, concrete and rebar tangles, rusty barrels and pipes, etc.

Step 7: Compound Entrance - Building the Prop

Apocalyptic scene overall:

We have a huge driveway, so we had the chance to fill it up with a lot of junkyard-ey stuff to create the apocalyptic feel. The overall scene set the stage, and then as guests progressed close to the house, we had an active part of the scene with smoke and flame, spraying water, sirens, and “armed guards” (neighbor teenagers with nerf guns).

Broken Water Main:

To simulate a broken water main, we fed a garden hose with a power wash nozzle through a broken PVC pipe, for looks and positioned it to get a nice vertical spray close enough to the path to make guests nervous, but not likely to get them wet .

Gunshots?? => Firecracker:

We included one of FrightProps’ electric flash-crackers in the animated part of the scene. This is a really loud firecracker effect, and added a whole bunch of scare to our effects. We place it right near the trigger, so that guests would really get an earful when they triggered the scene.

Broken Gas Main:

We simulated a broken gas line to add some fire to our opening scene (can’t get enuff of that!). We ran a rubber propane hose from a BBQ-style propane tank up through a 10” diameter chunk of pipe with jagged ends – once again, going for that gnarly look. In the end we fastened a “flower head”-style propane burner to generate the flame.

To light the gas we positioned an electric igniter above the burner using stiff metal and more baling wire. Positioning the igniter was the trickiest part of the setup because propane will not ignite if the igniter is too close to the burner. After testing we found that keeping the igniter in the center about 2-3 inches in front of the burner made for consistent lighting. We also used a pressure regulator to set the pressure coming out of the tank at a consistent level.

Testing:

• Now that all of the props are setup we recommend testing before moving to audio and programming of the controller. Test by simply plugging in power to each device and assure everything is in working order.
• Power to the water solenoid should open the water line and allow for water to go spewing out.
• Power to the firecracker should wake the neighborhood with snapping sounds and power to the electric igniter should cause it to glow red.
• When testing the igniter it is important to time how long it takes to heat up to glowing hot red. This time will be used in programming the scare effects to line up with your fiery blaze.
• Next, test the gas solenoid along with the igniter to assure the propane ignites. Be safe and have fun!
• Finally, upon powering up the whole thing you will begin to hear the looping of your ambient audio track. Then it is just a simple walk in front of the motion sensor to trigger the scare!

Step 8: ​Compound Entrance Controller and Audio

Controller:

After some deliberation and testing, we decided on the following programmed sequence of the FrightProps PicoBoo AC:

• 00s - Trigger - Passive InfraRed sensor (PIR)
• 00s - AC1 ON - Solenoid valve for water; electric firecracker; and igniter for propane gas
• Scare audio for the first 8 seconds is a mix of police sirens, fire truck horns, and car alarms.
• 08s - AC2 ON - solenoid valve for propane gas
• Scare audio becomes a loud tornado siren, then at about 12s begins a robotic voice warning people that zombies are approaching, and they should move quickly to the compound entrance for safety :D
• 22s - AC1 and AC2 OFF; Scare audio ends; animation sequence ends

The initial 8 seconds gives the igniter time to heat up so that it will effectively ignite the propane spewing until everything is turned off and the controller returns to ambient mode.

Note the picture of the layout labeled with the props positioned. The initial props are before the gas line to allow time for party participants to walk through and be wowed by FIRE.

Wiring:

Because this was an outside scare covering a large area, we used a large 2,000 watt powered speaker, like DJs use at good-sized gatherings. This is wired to the controller with a mini stereo cable plugged into line-out of the PicoBoo AC.

We used a passive infrared (PIR) motion sensor to trigger this prop. It’s mounted with some Velcro inside one of our scrap metal pipes, and wired to the PicoBoo AC controller with extra sprinkler wire so that the trigger is a decent distance in front of the initial props.

The FrightProps PIR wires are connected to the PicoBoo AC as follws:

• Black & White -> Negative
• Red -> Positive
• Green -> Trigger In

Only 3 of the 4 colors in the PIR wiring harness matched the colors in the sprinkler wire we used to extend it further from the controller. So here’s a *Tip: When using extra wire like our sprinkler wire, and the colors don’t match, be sure to write down the color mapping and attach labels or colored electrical tape to avoid any headaches.

We positioned the speaker, controller, and power strips under the overturned pickup truck to keep it out of the weather, and mounted the PicoBoo AC and cabling to scrap OSB for strain relief and neatness.

Audio:

Our audio files came from a variety of open source materials on YouTube and other websites, and our own recordings. We edited and assembled them using the wonderful open source audio editor, Audacity.

The FrightProps controllers allow for both an ambient sound track … while your victims (er, guests) are approaching the trigger, blissfully unaware; and a Scare sound track, to accompany the animations when the prop is triggered by your victims.

For the ambient track, we used some light traffic noises to give a city-like feel. The scare sound is a mix of police sirens, fire truck horns, and car alarms which slowly increases in volume until the 8 second mark, when the igniter is hot enough to light the propane and we get FLAME! At that mark, the scare audio adds a very loud tornado siren, and then 4 seconds later a loud public address announcement warning that “zombies have been observed approaching your position, proceed directly to the compound entrance for safety!”

*Tip: Make sure to contact your local police department if using loud sounds outside. We had a visit from two nice police officers very early in the evening (7:20pm!) to ask us to turn it down a little. Of course they knew it was Halloween. Hey

On all their controllers, FrightProps recommends recording your audio before recording the animation sequence (power relay on/off timing), so that you have the audio cues to help you as well as a stopwatch.

Step 9: Vicious Dog - Overview

This was a store-bought prop which turned out to have rather underwhelming effects, so we decided to spice it up a little (evil grin). The dog's face and jaws were indeed pretty evil looking. But its bark was disappointingly low key, and its "animation" was a real bummer: a small internal motor with an off-center cam made it vibrate a small amount: so little that if it wiggled like that welcoming you home, you would think it was sick. So we found some better barking effects, and experimented with ways to make the animation a little more "robust" (evil grin v2.0).

Step 10: ​Vicious Dog – Materials

Here's the list of materials we used. As with all the parts of this, many of these are what we had on hand, and substitutes would work fine.

• 1/4" plywood, about 4'x4'
• 1/4" ABS Plastic, about 4'x4'
• 3/8" OSB (chipboard), about 4'x4'
• 2x4's and 2x3's (interchangeable; these are just what we had on hand) 4x4's
• Deck screws for fastening the wooden frame together
• Drawer slides, 24” extension and 100 lb weight bearing capacity, found at Lowe’s
• 1/4" bolts and nuts, about 1", for attaching the drawer slides to the plywood deck
• Pneumatic cylinder, 15" stroke. McMaster-Carr PN 6491K36
• Directional Control Valve. McMaster-Carr PN 6196K24
• 1/4" bolts and nuts, about 2", for attaching the pneumatic cylinder to the plywood deck
• Air compressor (typical home workshop style, capable of up to 100 psi).
• Air hose and fittings
• PicoBoo AC Controller
• Beam Sensor trigger
• 14 gauge primary electrical wire for connecting Audio speaker, 8 ohm, and speaker wire
• Old stereo receiver for amplifying the sound
• Doorbell wire for connecting the beam sensor trigger to the PicoBoo AC
• Zip ties for organizing cables and mounting parts
• Dark blue velvety cloth for hiding the support frame

Step 11: Vicious Dog - Building the Prop

The dog itself was a store-bought prop, so we won't describe making it. But if you want something like this, you could make it from a large block of styrofoam, as we did with the head of our anaconda snake (see later steps), or even papier-mache.

Our key challenge with this one was getting the dog, which weighed about 30 pounds and was made of a medium density foam which had a high coefficient of friction, to slide across the top of its support stand. We tried several different approaches.

• The first was to cover the slide surface with a sheet of ABS plastic … too much friction.
• Next, we tried mounting it on a connecting rod that was higher, and kept it completely off the surface … no friction, but since the dog had only one attachment point, we got too much vibration which would have torn it apart.
• The solution: ball bearing drawer slides, the type used for cabinet-making. We found a pair with 24” extension and 100 lb weight bearing capacity at Lowe’s for about $19, and they worked great. You can see those in the photo above, as well as the ABS plastic, which we left in place.

Step 12: Vicious Dog Actuator - Pneumatic Cylinder

We decided that to really be scary, we needed the dog to lunge out toward visitors, so we embarked on an actuator to make that happen.

Our initial design used an electric motor to turn a linkage arm. As with a couple of the other props, we had challenges overcoming friction with this approach. And for this one, we really wanted a high speed lunge. With other props (snake head and chain saw), we used linear actuators, which are available in a range of power and speed combinations. (For a non-scientific sampling of linear actuators we found that can be powered with a 12VDC 5-10A power supply, see the Chain Saw section).

But for Mad Dog, we really wanted a high speed lunge, so we went with a 15" stroke pneumatic cylinder. We controlled it with a Directional Control Valve. We charged the pneumatics with our typical home workshop air compressor, capable of up to 100 psi.

The photo above shows the pneumatic cylinder mounted to the underside of the doggy's support table (the upper side, with the drawer slides, is visible in the previous section). At the left end of the photo you can see how we attached the dog to the cylinder: we started with a "long nut," or coupler nut, and welded a bolt to its side sticking up perpendicular. That bolt then connects to the metal support pole that is built into the interior of the dog's body.

At 100 psi, the dog really leaped out ferociously, but with so much force that we were afraid a few cycles would rip apart the support mechanism and slides. So we dialed the pressure back to about 27 psi, which powered the dog to extend in less than a second, and still left the prop intact.

Step 13: Vicious Dog Controller and Audio - FrightProps PicoBoo AC

We found some really ferocious barking clips on YouTube, and some mean growling. The dog lunged out from its resting spot in about a second, and we allowed it to stay out for 3 seconds, then retracted it and left it growling for 5 more seconds. So the total Scare audio is 10 seconds: 4 seconds of barking, and 6 seconds of growling.

Audio output level: we wanted louder sound than provided by the 10 watt output from the PicoBoo AC. So we ran a mini stereo output to an old stereo receiver, then used that to drive a speaker. We used the good old-fashioned rotary volume knob to achieve a pleasantly “attention-getting” :) barking sound, probably at about 50 watts.

This prop, like most of our others, used the PicoBoo AC. And like most of our others, in retrospect we would have used the regular PicoBoo, which is DC, not AC. For a discussion of the pros and cons of DC vs AC controllers, see the Step on FrightProps Controllers.

Like all controllers, this one needed a trigger to initiate the Scare animation and audio. We used a beam sensor from FrightProps, positioned about 5 foot in front of the prop.

The Animation Sequence is:

• 00s - Trigger (beam sensor)
• - AC1 ON - Pneumatic cylinder Extend
• - Scare audio is loud ferocious barking
• 01s - AC1 OFF
• 04s - AC2 ON - Pneumatic cylinder Retract
• - Scare audio is loud growling while dog is retracting
• 05s - AC1 OFF
• 10s - Scare audio ends, animation sequence ends

Step 14: Zombie in a Box, for Shipping to Another Zombie Research Facility - Overview

This prop was designed to look like an “innocent” crate, just like you would find at any apocalyptic compound for supplies of food, ammunition, or whatever.

But when you approach it, you see stenciled red labels of “DANGER” and LIVE ZOMBIE” (hmm, I guess that's an oxymoron!! :) ), etc, and instructions to ship the contents to another zombie research facility for further testing. You hear a low grunting and groaning from the semi-conscious zombie within ... and when you get right up to it, the zombie inside goes berserk, screaming and thumping the lid trying to escape and eat your brains – thank goodness it’s chained up tight!!

Step 15: Zombie in a Box – Materials

Here's the list of materials we used. As with all the parts of this, many of these are what we had on hand, and substitutes would work fine.

• Two discarded wooden pallets and some scrap plywood to make a box that looks like a packing crate.
• Plastic chains and a padlock
• Paint and stencils.
• A “lid thumper” inside the box, made from a piece of 2”x2” lumber and two guides
• A cam wheel to drive the thumper, cut from a 1-1/8” thick piece of plywood.
• 12VDC motor, an old windshield wiper motor taken from a wrecked car at the pick n pull junk yard.
• Red floodlight bulb and base.
• Power cords
• 14 gauge primary electrical wire
• Electrical quick disconnect connectors
• FrightProps Picoboo AC controller
• FrightProps Beam Sensor trigger
• Sprinkler wire (18-5) for connecting the beam sensor trigger to the PicoBoo AC
• Audio speaker, 8 ohm, and speaker wire
• Zip ties for organizing cables and mounting parts

Step 16: ​Zombie in a Box - Building the Prop

We made the crate from a couple of old pallets and some scarp plywood – as with all the decorations here, the goal was a gnarly looking thing. We sized it to be big enough to hold a zombie. This one required only your typical home tools: table saw (we could have just used the circular saw), drill/drivers, and hand tools.

The thumping mechanism is an 18” length of 2”x2” lumber, with the bottom end cut at about a 20 degree angle to mesh well with the cam (next).

We used a sort of cam wheel to drive the thumper. We cut this from a 1-1/8” thick piece of plywood. We started by cutting a round piece about 6” in diameter, and then cut rounded notches into it so that the lid thumper, held down by the weight of the lid, would bump up and down on it as it turned. We mounted these, the controller, the speaker, and the light inside the box as shown in the picture.

Step 17: Zombie in a Box Actuator - 12VDC Windshield Wiper Motor

One of our first “shopping” forays was to the pick n pull junk yard. We pulled three old windshield wiper motors and brought them back, eager to start the world turning. As it turned out, the WW motors were a pain to work with because the connectors were hard to access, had mounting bolt patterns that were hard to adapt to plywood instead of shaped car parts, and were a little bunged up. So for most of our props, we ordered new motors to avoid the mounting and wiring hassles. But one of the WW motors mounted well enough that we could use it for this prop.

We bolted our homemade cam wheel (see previous section) to the end of the motor’s spline shaft, and then mounted the motor and cam to the base of the box using a couple of L brackets. We ran the wires away from the cam to the controller.

Once the motor and cam were in place, we positioned the thumper shaft above it, and mounted it using some loose-fitting plastic U-brackets so that is could slide up and down easily using them as guides.

Step 18: Zombie in a Box ​Controller and Audio - PicoBoo AC

This prop used the FrightProps PicoBoo AC.

• Output 1 started and stopped the 12VDC motor that actuated the lid thumper.
• Output 2 turned the red floodlight on and off.
• The trigger was a beam sensor from FrightProps, positioned about 2 feet in front of the prop. WE would have preferred a little longer distance, as this allowed a few victims to pass near without triggering it :) . But, the room and decorations arrangement didn’t allow for a better position.
• Ambient audio: we found some great zombie grunts and groans on YouTube, and played those at a low level for the ambient sound track.
• Scare audio: we found another set of really loud, agitated zombie screams and grunts, and played those loud for the scare track.

The animation sequence is:

• 00s - Trigger - beam sensor
• - Scare audio is a series of loud zombie grunts, groans, and snorts throughout
• - AC2 we pulsed rapidly and sporadically ON and OFF throughout, making the amber light flash wildly
• 03s - AC1 ON - Activate motor for box lid thumping noises
• 05s - AC1 OFF
• 13s - AC1 ON - motor
• 16s - AC1 OFF
• 23s - Scare audio ends, animation sequence ends

The combination of the scare audio, the box flashing, and the red light flashing inside was a real attention getter, and a lot of fun. We initially scripted the thumper to run nearly continuously through the full scare animation period. But the thumping was crazy loud in an inside room, and throughout our testing and dress rehearsals we scaled the thump time back to half, then a third, and finally to less than a quarter. But that itself was part of the power of this animation: when the trigger tripped, the zombie started screaming and the light started flashing, making the guest jump. 3 seconds later, the lid started thumping, prompting another jump. Then the lid stopped thumping, but the screams continued – as if the zombie had realized it couldn’t escape! :). Then after 8 more seconds, the lid started going again, continuing the unpredictability of this scare. Finally, it all shut down. Whew!

Step 19: Chain Saw in Guest Bathroom Shower - Overview

This was inspired less by zombies than by good old classic Halloween horror scenes. How can it get any better than a chain saw rotating down from a hidden spot, with roaring sounds?

Well, how about a few nuances of timing? Our trusty PicoBoo AC controller played a very low, subtle but spooky ambient sound track of woodsy noises: crickets chirping, owls hooting in the distance, coyotes howling in the further distance, bats flapping their wings, and footsteps crunching in fall leaves. Cool!

So when a victim / guest comes into the bathroom and closes the door, the magnetic door sensor triggers the controller … and for 15 seconds, absolutely nothing changes. Just a few low, spooky noises while the victim checks their hair in the mirror, adjusts their costume, and then sits down to let biology happen … and then after 15 seconds, suddenly up starts the chain saw … a couple of unsuccessful pull start attempts, then a start, then the hallmark noise of revving up and running full open. Meanwhile, the zombie arm lowers the saw from its hidden location behind the curtain, and then slowly retracts it … during which time the victim is trapped by having costume pieces draped around their knees! Boy, we felt devious setting this one up!

Step 20: Chain Saw - Materials.

Here's the list of materials we used. As with all the parts of this, many of these are what we had on hand, and substitutes would work fine.

• Plastic toy chain saw, painted black and gnarly
• A homemade zombie arm to "hold" the chain saw: latex glove with makeup, flannel shirt, and stuffing.
• Plywood, 2x4's, and 4x4's to make a support table
• 12" inch Linear Actuator w/Tilt Brackets & Mounting Heavy Duty 12V DC 200lbs Max. http://www.ebay.com/itm/12-inch-Linear-Actuator-w...
• 110VAC Solenoid to control the toy chain saw's trigger
• FrightProps PicoBoo AC Controller. www.frightprops.com/controllers-electronics/frigh...
• FrightProps PicoVolt Controller. http://www.frightprops.com/controllers-electronic...
• Magnetic door sensor switch by Directed Electronics. http://www.amazon.com/gp/product/B0009SUF08?ref_=...
• Doorbell wire (18-2) for connecting the magnetic trigger to the PicoBoo
• 14 gauge primary electrical wire
• Electrical quick disconnect connectors
• Audio speaker, 8 ohm, and speaker wire
• Zip ties for organizing cables and mounting parts

Step 21: ​Chain Saw - Building the Prop

We already had on hand a toy plastic chain saw, which made a pretty decent chain saw noise when you pulled the trigger, and even ran its chain (dull plastic) around the chain bar. Both effects lasted about 9 seconds. We made a zombie arm to "hold" the chain saw, using a latex glove with lots of ghoulish makeup, a flannel shirt, and some stuffing. We fastened a triangle of plywood above and behind the saw to provide the attachment for the linkage arm.

We built the support table you see in the picture using scrap plywood, 2x4's, and 4x4's. The initial actuator design had a 2-part linkage arm made of ABS plastic, so we cut a large slot down the center of the table top to allow it to move.

We struggled mightily with this linkage arm. We did a lot of trial and error with different attachment points on the chain saw and its lever arm. But the bottom line was, the ABS plastic had a large amount of flexibility and was simply not a good choice for the actuator.

We replaced the ABS plastic with a length of square tube, and then with a ball joint linkage arm. Both were improvements, but we still couldn’t get a smooth motion. This stemmed from the fact that electric motors have, of necessity, a little slop in the gears. When the saw was at the top or bottom of its quarter-revolution movement, the slop meant that its action was jumpy. We eventually solved this with a different actuator, described in the next section.

Step 22: Chain Saw - Linear Actuator, 12 Inch Travel

As discussed in the previous section, we started with an electric motor as the actuator, and several different attempts at linkage arm designs, but there was enough slop in the linkage and the motor gears that we couldn't achieve a reliable lowering and raising.

We eventually replaced the motor and linkage arms with a linear actuator. We bought ours on EBay, at deezeeauto. We used a model with 12" linear travel, and 225 pound (1000N) capacity. The linear actuator was much more suitable for tilting the chain saw down, then up, at a controlled speed than the motor and linkage.

The pictures above show the linear actuator, as well as early work on the motor and linkage.

Step 23: Chain Saw Controller and Audio - FrightProps PicoBoo AC and PicoVolt

Two Controllers:

• This prop used two controllers, a PicoBoo AC and a PicoVolt. We had to do this because we needed the linear actuator to run in forward and then reverse, which required reversing the polarity of the DC power to the actuator.
• So we used Output 1 of the PicoBoo AC to activate the solenoid that pressed the toy chain saw’s trigger. Output 2 of the PicoBoo AC was unused.
• The PicoVolt provided DC power directly to the linear actuator. The actuator speed and direction are controlled by the Speed dial on the PicoVolt. So we set the PicoVolt’s Speed dial at 100% Forward to lower the saw, and 100% Reverse to raise it.
• As with some of our other choices of controller, in retrospect we could have done this more simply. We could have used a PicoBoo Plus, with its four relay outputs, to control forward, reverse, and chain saw trigger.
• Ambient audio: we used a track of spooky woods noises at very low volume: footsteps in crunchy leaves as the majority, and then at 15 second intervals three different creatures: owls, bats, and coyotes.
• Scare audio: Since we wanted a 15 second delay after the door closed and the trigger activated, the first 15 seconds of the scare track was simply a copy of the ambient track,. Then at the 15 second mark, the audio changed to sounds of a chain saw starting, then revving up, then running loud, and finally tapering off and stopping. This audio sequence lasted 24 seconds, the time required for the linear actuator to rotate the saw down by 90 degrees, and then return it to upright.

Trigger and Wiring:

• This prop used a magnetic door sensor, similar to those found in home security systems. It had three screw terminals: Normally Open (NO), Normally Closed (NC), and Common. We wanted our scene to trigger as the door was closed by someone entering the bathroom, so we wired it to the controllers using Common and NO. We need about a 20 foot run from the door to the controller because of following a discreet route along the wall. We were able to use 2-conductor doorbell wire for this run, less expensive than the 5-conductor sprinkler wire we used for other sensors. This was because the other sensors required 2 wires for a power source and 2 more for the trigger signal. The magnetic switch didn’t require a power source since the magnet itself induced the electric current.
• Since we had two controllers in this prop, we needed them to both trigger simultaneously. We therefore wired the switch to Trigger Negative and In on the PicoBoo AC, and then connected a jumper wire from those terminals to their matching terminals on the PicoVolt.

Animation Sequence:

• 00s - Trigger - magnetic door sensor
• 15s - AC1 ON for 1s to activate the chain saw solenoid
• chain saw noise begins on Scare sound track
• Rotate the PicoVolt Speed dial to 100% Fwd
• 16s - AC1 OFF
• 24s - AC1 ON for 1s to activate the chain saw solenoid
• 25s - AC1 OFF
• 27s - Rotate the PicoVolt Speed dial to 100% Rev
• 33s - AC1 ON for 1s to activate the chain saw solenoid
• 34s - AC1 OFF
• Scare audio track shifts from high revving chain saw to chain saw trailing off
• 42s - AC1 OFF
• Rotate the PicoVolt Speed dial to 0%
• Scare audio track completes

Step 24: “Soylent Green” Cuisine Prep and Serving Machine - Overview

This prop gives a whole new meaning to the term “food processor!” It was inspired by our memory of the classic movie starring Charlton Heston about a future where the evil corporate overlord manufactured food called soylent green because humans had killed off the oceans and farming capability. In the final scene, Heston is carried out of the soylent factory on a gurney, injured and semi-coherent after an illicit investigative mission into the factory, screaming out his discovery: “Soylent is people!” “Soylent is people!” “Soylent is people!”

Well, Charlton, we’ve uncovered a far more gruesome truth: “Soylent is Zombies!” “Soylent is Zombies!” “Soylent is Zombies!” From this twisted inspiration came the motivation to build a soylent machine to serve our actual hors d’ouvres.

We started with the discarded treadmill in the garage. The motor and deck still worked, so we figured we could use that as the output conveyor belt, serving up tray after tray of appetizers – green, of course: green salsa on spinach chips; avocados, guacamole, etc. Yum!

So what could we use as the evil box “feeding” the conveyor belt with its nutritious ground zombie cuisine?? We wanted something big and boxy and rusty, and it had to have a hopper on top with zombie body parts sticking out and bouncing up and down as it fed the parts into the business end of the machine. A friend said that her school had just replaced some of its aging swamp coolers, so we went over and picked one up, along with some scrap ducting material. Voila! Everything we needed to make the best health food of the season!

Step 25: ​Soylent Green Machine - Materials.

Here's the list of materials we used. As with all the parts of this, many of these are what we had on hand, and substitutes would work fine.

• An old evaporative cooler (“swamp cooler”) that was discarded by a local school – rusty and gnarly, but the motor still worked.
• Some old sheet metal heater duct.
• A discarded treadmill – beat up, but still working.
• 3/8” OSB (chipboard)
• Vinyl.
• An old discarded wooden crate we used as a support table.
• Old corrugated sheet metal roofing – the rustier the better, of course
• FrightProps 12VDC high torque motor, PN 0956-MOT2. http://www.frightprops.com/electric-motors/motors... (the MOT2 is not currently listed; perhaps they're sold out)
• 14 gauge primary electrical wire
• Electrical quick disconnect connectors
• Zip ties for organizing cables and mounting parts

Step 26: ​Soylent Green Machine - Building the Prop.

Could that old treadmill possibly still work? Could we turn that swamp cooler into a credible “food processor?” Well, nothing ventured, nothing gained....

Sure enough, the treadmill still worked. We disassembled it, removing the vertical support bars but keeping the control head and deck. We gave it a thorough scrubbing, and it was good to go!

The swamp cooler had a great native mechanism, a drum-shaped fan mounted on a horizontal axis. We quickly realized that if we just attached a few “bumps” to the surface of the drum, those bumps would act like cams and make zombie arms and legs bounce up and down in a gruesome ballet of food processing! We made the bumps out of scrap sheet metal, and bent the pieces into arc shapes that we screwed into the fins on the drum.

For the hopper, we took a piece of square heating sheet metal duct tube, trimmed off an angle, and screwed it into the top panel of the swamp cooler. We then mounted three short pieces of 3” PVC pipe at angles slightly off vertical; each of these tubes was the guide for a longer zombie arm or leg – the ones that did the bouncing. To make the drum rotate, we mounted the 12VDC motor on the side, and attached it to the drum’s native pulley with a linkage arm. This worked out great, turning the drum continuously, and making the zombie arms and legs bounce up and down convincingly. Finally, to mount the whole apparatus, we used a crate that had been abandoned by a nearby business, about 12 feet long. 3.5 feet high, and 3 feet wide. Serependitiously, it was a perfect match for the size of the treadmill and swamp cooler. We screwed the two large devices to the top, attached some old rusty corrugated metal to the sides.

Step 27: ​Soylent Green Machine - Actuator.

We had to alter the mounting position of the cooler's cylindrical fan ("hamster cage"), so we couldn't use the original motor, even though it still ran despite the rust. So we mounted a separate 12VDC motor from FrightProps to a bracket on one side of the fan, and connected it to the drive pulley with a ball joint linkage arm. We chose the FrightProps high torque motor because it's also low speed: 6 RPM, or ten seconds per revolution. This was perfect for us, since we wanted it to run continuously, turning the cage slowly so that the zombie legs and arms in the hopper above would bounce up and down on the humps we added to the drum.

Step 28: Monster Flame-Throwing Anaconda Snake in Spittoon Lagoon - Overview

Everything's bigger in Texas, where Gary spent a few years, and that certainly influenced our snake! This is a 90-foot long Anaconda with its 6-foot head at one end of the pool on the rocky outcropping and the tail in the hot tub at the other end. Gary’s vision was that the head would have sinister red eyes, flame throwing nostrils, and a water spitting tongue. When the snake felt threatened, it would “awake,” rotate toward the source of the disturbance hissing and throwing flame. Then the tail, much closer to the disturbance, would lift a screaming hapless victim out of its bubbling swampy nest right next to the adventurous party guest who dared to enter the snake’s lair. With the number of actuators and devices going on, we had to use two logic controllers, but the whole thing was triggered by a single beam sensor near the approach to the tail. Somehow we managed to pull the whole thing off!

The snake’s head is carved from a large Styrofoam block, which started out 6’ long, 3’ wide, and 2’ tall. You could carve this by hand, but this is another place where Gary’s business helped us out: they also manufacture precast concrete, and they do a lot of custom pieces. So they have a CNC router that cuts shapes sent to it from the CAD system. With flame, water, movement, and light, this was the most complex animation in our arsenal, and we used Fright Props' PicoBoo Plus controller, which has four output relays instead of the two relays found in the other controllers we used.

The snake's body is made from spandex fabric two yards wide and 30 yards long sewn around an 18" diameter section of flexible heating duct (similar to dryer vent duct: plastic with spiral coiled wire to give it its shape). Gary has an industrial sewing business, which made short work of sewing 30 yards of fabric into a tube!

The snake's tail is a nylon tube stuffed with padding. The “prom queen” is a mannequin decorated by hostess Lynn and our very artistic friend, Betsy. We initially envisioned the snake’s victim as a human, perhaps trapped and about to be zombie-fied. But as we dug through the boxes of old costumes and came up with an old prom dress, we had to try it on the mannequin. Then, of course, someone grabbed one of the many zombie masks lying around and out it on her. The juxtaposition of the two images was too much fun, so the design immediately evolved into a zombie prom queen. The lifting mechanism is a ten foot long stick of 1.5 inch IMC conduit, used as a lever which pivots on an old tether ball pole. The prom queen is on the long end of the lever, about 70" from the fulcrum. The short end of the lever has a counterweight and a motor that turns a shaft arm attached 40" from the fulcrum. The prop is controlled by a PicoBoo AC from FrightProps, and triggered by a beam sensor.

The next few steps focus on the details of the head, and then several on the tail.

Step 29: ​Snake Head - Materials.

Here's the list of materials we used. As with all the parts of this, many of these are what we had on hand, and substitutes would work fine.

• Large Styrofoam block
• Polystyrene coating
• Paint
• Rapid set cement
• Expanded lath metal
• Garden hose, 10 feet
• Propane gas hose, 15 feet

• Heavy Duty Linear Actuator 12" Inch Stroke 200 Pound Max Lift DC 12v

• Water solenoid
• Gas solenoid
• Power cords
• 1/4" nylon rope for suspending the electrical and propane connections behind the snake head to relieve strain
• 14 gauge primary electrical wire
• Sprinkler wire (18-5) for connecting the beam sensor trigger to the PicoBoo AC, and for extending the trigger signal from the snake tail to the PicoBoo Plus at the snake head (the sprinkler wire was relatively inexpensive, and the colors of the 5 conductors were a close match for the colors of the beam sensor wires)
• Fright Props Picoboo Plus controller.
• Electrical quick disconnect connectors
• 2 red R30 floodlight bulbs
• Copper tubing, 1/4 inch, 12 feet
• Connectors for the copper tubing
• Igniters, capable of reaching 1200 degrees C in 6 seconds
• Water hose nozzle
• Water hose pressure regulator
• Propane pressure regulator
• Propane tank (BBQ style)
• Audio speaker, 8 ohm, and speaker wire
• Zip ties for organizing cables and mounting parts

Step 30: Snake Head - Building the Prop

We started with a large styrofoam block, 6’ x 3’ x 2’, and carved the head shape from it. As mentioned in the Overview Step, the carving was done by a machine at Gary’s business. But it could have been done by hand as well. We coated the head with polystyrene to give it a little sturdiness.

We then sliced the head in half lengthwise. This allowed us to route the power cords, copper tubing for propane, and water hose through the snake head from the rear to the front. We carved initial routing paths for these, then used a 6 foot long auger drill bit to drill the path the rest of the way through. Later, after all the routing and testing were done, we glued the two halves of the head back together.

We placed the light bulb bases in the holes we had carved for the eyes, and routed the power cords through our holes back to the rear of the head, where they would later be connected to the sources and switches. We lined the eye sockets with aluminum foil for heat protection, and screwed in the red flood lights. Once they were in place, we painted the thin black vertical oval shape for the eye slits.

We routed the water hose through its access hole, and mounted it and the power spray nozzle, set to jet position, at the end of the tongue.

We routed the copper tubing for propane gas through its access holes, and out the nostrils. Our initial design used pilot lights for ignition of the main flame, so for each nostril we had a 1/8” diameter pilot tube with very low pressure gas, and a ¼” main tube with higher pressure gas. The pilot lights turned out to not work reliably, since the prop was outdoors: even a small wind blew the pilot lights out. So we replaced the pilot lights with electric resistive igniters. These were not susceptible to wind, but they injected another issue, one of timing: they required 8 seconds to heat up to 1200 degrees C, at which point they glowed bright red and could reliably light the propane. But by adjusting the timing of the other elements of the scare, we were able to accommodate this delay. In retrospect, we could have tried spark igniters, which may have given us the imperviousness to wind that we needed, as well as instant gratification :) .

Once all our “toys” were placed in the head and their supply hoses and pipes routed through to the rear (with about five feet of excess to allow for connections), we connected each to the source hoses, valves, wires, etc. at the rear of the head. Several of the photos show the somewhat large, ungainly bundle that resulted. We supported this bundle with a rope leading up to an overhead tree branch for strain relief, and this allowed the snake head to turn reliably.

Mounting the snake head to allow rotation and rising was a trick. This part required a lot of metal work, drilling, welding, cutting, and forming. We designed a horizontal base plate of flat ¼” steel. Near the front we drilled a hole that allowed a pipe to pass through vertically. We welded a piece of pipe firmly in place in this hole in the fixed plate, and then passed a slightly smaller pipe, with a flange on top, through it to serve as the attachment to the bottom of the snake head. The “rise and rotate” pipe flange not only attached to the snake head, but had a steel “T” with legs and wheels attached. Surrounding these concentric pipes we built a pair of curved ramps, so that the wheels attached to the inner pipe would follow the curves and rise up as they rotated.

In retrospect, we would eliminate the rise aspect of this prop and go with rotation only. The rotation of 45 degrees was very observable and rather ominous, but the rise was barely noticeable. And the rise required a great deal more force, and caused us a lot of challenge with finalizing the mechanics. Without the rise, the rotation would have been much simpler.

Step 31: Snake Head ​Actuator - Linear Actuator, 8 Inch Travel

As with the chain saw, we started with an electric motor and ball joint linkage. And like the chain saw, we realized we needed more force, and shifted to a linear actuator. Several of the photos show the way we mounted it to the base plate and the rise / rotate pipe, and the video shows it extending and retracting to rotate the snake head.

Step 32: Snake Head ​Controller and Audio - FrightProps PicoBoo Plus

We used a FrightProps PicoBoo Plus to control timing of the snake head prop motions and audio.

The Snake Head and Snake Tail are synchronized, even though each has its own controller, actuator, and audio. Both the head and the tail were triggered by a single Beam Sensor, which was wired normally to the PicoBoo AC at the tail, and then two wires extended the trigger signal from there to the PicoBoo Plus at the head.

The wiring diagram in this section shows the trigger, power outputs and audio connections at the head. The Snake Tail section has the wiring diagram for the tail.

The animation sequences for the head and tail are:

Snake Head Animation Sequence:

• 00s 4 ON - Eyes and Igniters
• 10s 1 ON - Actuator Extend
• 20s 3 ON - Flame and Water
• 30s 1 OFF - Actuator 3 OFF - Flame and Water
• 40s 2 ON - Actuator Retract 3 ON - Flame and Water
• 60s OFF everything

Snake Tail Animation Sequence:

• 00s - No Action. Scare audio plays a copy of the ambient track
• 30s - 1 ON - Activate motor for lifting Scare audio becomes a loud female scream
• 40s - 1 OFF - Deactivate motor Scare audio again plays a copy of the ambient track
• 60s - Scare audio ends, animation sequence ends, matching the snake head animation

The ambient sound for the snake head is a spooky woods sound, with footsteps in crunchy leaves, and some infrequent owls, coyotes, and bats. The scare sound is a loud hissing sound. As with our other audio, we edited the audio using Audacity.

This prop was outdoors, and needed moderately high audio volume. We got plenty of volume from the PicoBoo Plus' 30W audio amp and a non-powered speaker (note that the PicoBoo Plus has a 30W amp, while most of the other PicoBoo models we used have 10 amps).

Step 33: Snake Head Excitement - Repairing a Major Burn Damaged Section

Our party ran for two nights, with the first night being a fundraiser for a local high school traveling sports team. An hour or so into that party, someone came running into the house yelling, “the snake is burning! the snake is burning!” We chuckled, and said “it’s supposed to!” To which she replied, “no, really!”

So we ran outside, and sure enough, there was a decent fire burning the styrofoam on the left side of the snake head (pic above). Darn those flame-throwing props! So we had to put the snake on injured reserve for the rest of that night.

The next day, we made repairs and improvements. The hole in the snake’s head was the size of a basketball, and the electric igniter was hanging by its insulated supply wires. The igniter turned out to be damaged, and we had to replace it. There was no time to order another “fast” igniter, requiring 8 seconds to reach ignition temperature; so we had to use a spare igniter we had on hand for a gas-fired clothes dryer. It work OK, but required 18 seconds to heat up, so we had to insert an additional ten second delay into the animation sequence.

To repair the hole, we filled the majority of the empty space with fiberglass, routing the copper tubing and the igniter through it. We then covered that with expanded metal lath, and then covered the entire area around the nostrils with rapid set cement. This gave it the fireproofing we should have built in from the beginning. So in three hours, we were back in business! On the second night, the repaired snake head worked flawlessly. There's another pic of Dr. Gary conducting the surgical repairs above.

Step 34: Anaconda Snake Tail Lifting Zombie Prom Queen - Overview

The snake's tail is a nylon tube stuffed with padding. The prom queen is a mannequin decorated by our very artistic friend, Betsy. The lifting mechanism is a ten foot long stick of 1.5 inch IMC conduit, used as a lever which pivots on an old tether ball pole. The prom queen is on the long end of the lever, about 70" from the fulcrum. The short end of the lever has a counterweight and a motor that turns a shaft arm attached 40" from the fulcrum. The prop is controlled by a PicoBoo AC from FrightProps, and triggered by a beam sensor.

Step 35: Snake Tail - Materials

Here's the list of materials we used. As with all the parts of this, many of these are what we had on hand, and substitutes would work fine.

• A mannequin, an old high school prom dress, wig, and makeup
• 1.5" IMC Conduit, 10 feet
• 1.5" conduit coupler
• 5 gallon bucket and cement for counterweighting the lifting end of the lever arm
• Old tetherball pole stand for use as the fulcrum
• 1/4" braided nylon rope, 10', and small pulley, for attaching the rotating motor arm to the lever
• 12VDC motor12VDC motor, Fright Props high torque model
• Power cords
• 14 gauge primary electrical wire
• Sprinkler wire (18-5) for connecting the beam sensor trigger to the PicoBoo AC (the sprinkler wire was relatively inexpensive, and the colors of the 5 conductors were a close match for the colors of the beam sensor wires)
• Picoboo AC Controller
• Electrical quick disconnect connectors
• 8 gauge solid copper wire, 20 feet, for allowing the tail to wrap around the mannequin's torso
• Audio speaker, 8 ohm, and speaker wire

• 5/8" all-thread rod, 24", with 2 regular nuts and 2 nyloc nuts for connecting the mannequin to the lever

• Zip ties for organizing cables and mounting parts

Items we had on hand to hide the lever mechanism and make the prop look apocalyptically gnarly:

• Old rusty barrel
• Large wooden beat up crate
• Camouflage netting

Step 36: Snake Tail - Building the Prop

Lever Arm and Counterweight

The lever arm for lifting the Prom Queen is a ten foot long stick of 1.5 inch IMC conduit. The fulcrum is an old tether ball pole. We started with a little geometry for the dimensions, then plenty of trial and error for fine tuning things (photos 1 and 2). Our goal was to have the prom queen start with her legs in the bubbling swamp snake's nest (aka hot tub), and then rise to look down at visitors as they walked across a bridge in front of her. So we wanted 60" or more of vertical travel at the long end of the lever, and we wanted to minimize the vertical travel at the short end. Also, the mannequin and her dress weighed about 15 pounds. We decided to position the fulcrum at about 70" from the prom queen, and 50" from the lifting end. We made a counter weight by mixing 50 pounds of cement in a 5 gallon bucket with a 3" pipe down its center so it could slide along the lever and we could adjust its position (photo 3). We were later able to reduce the lifting arm length to 40".

Step 37: Snake Tail ​Actuator - 12VDC Motor and 17 Inch Shaft Arm

We used a 12 volt high torque motor from Fright Props (part number 0956-MOT2). It turns at 6 RPM (one revolution every ten seconds). This motor does not have a parking feature, so we had to be careful with the timing of each lifting cycle to get it to stop at the same spot each time. We were helped by the fact that the zombie's weight naturally brought it to a stop at the low point in the cycle if we shut off power a split second before the low point.The motor has the simplest possible power leads, +12V and -12V DC. The motor is driven by a 12VDC / 10A power supply, also from Fright Props. We connected them with quick disconnects.

Fright Props sells a shaft arm for connecting to your rotary devices, PN 0956-LINK-ARM2, which provides a 2.5" radius of rotation. We needed a 17" radius, so we extended it by bolting on a piece of 3/4" steel square tube from Ace Hardware. The motor shaft arm is connected to the lever with a piece of braided nylon rope.

Step 38: Snake Tail Controller - FrightProps PicoBoo AC

We used a FrightProps PicoBoo AC to control timing of the snake tail prop motions and audio.

The Snake Head and Snake Tail are synchronized, and are described in detail in the Snake Head Controller step.

The ambient sound for the snake tail is a bubbling cauldron, to evoke mental images of a bubbling, roiling swamp that is the mutated snake's nest. The scare sound is a woman screaming. As with our other audio, we edited the audio using Audacity.

This prop was outdoors, but didn't need extremely high audio volume. We got plenty of volume from the PicoBoo AC's 10W audio amp and a non-powered speaker.

Step 39: Thunderdome (static Prop):

Somehow during the planning process, we decided we also needed a ThunderDome. I guess we just hadn’t mixed in enough pop culture references! It does fit with the apocalyptic theme, though, eh?! So we decided to build a geodesic dome from metal tubing. This turned out to be one of the easiest parts of the whole thing!

We did a quick web search, and there are many sites with info on this Buckminster Fuller classic design. We liked the instructions at the Hila Road Science Camp:

• Instructions
• The math

We wanted a 20 foot diameter dome. So based on the simple math at this site, we saw that we needed:

• 10 equilateral triangles with side length A-A-A, where A = dome radius * 0.61803 = 74.2”.
• 30 isosceles triangles with side length A-B-B, where B = dome radius * 0.54653 = 65.6”.

The Hila Road instructions tell you how to make triangles, assuming solid sides like cutout paper. We were going to use metal tubing to make just the shapes, so we had to think about the number of triangle sides rather than the number of triangles. This meant we needed

The two images below from Hila Road helped sort through the thought process. It turns out the blue pentagons are each made from five of the isosceles triangles. So we just had to think about the number of tubes to make a pentagon. And conveniently, the equilateral triangles constitute every location where there is a shared side between pentagons and equilateral triangles. So the number of tubes needed is:

• A (74.2”): 10 triangles * 3 A sides each = 30
• B (65.6”): 6 pentagons * 5 B spokes each = 30
• A (74.2”): 5 pentagons on the base course * 1 B side touching the ground but not another triangle = 5
• So we needed 35 A length tubes, and 30 B length.

So off we went to the hardware store, and bought 42 ten foot sticks of ¾” EMT conduit tubing, along with nuts and bolts and lock washers for joining them. We cut the 42 pieces to length, and then welded the leftovers together to make the remaining 21 pieces.

We flattened 2” at each end of each tube, and drilled a hole in each for the fastening bolts.

Now we were ready to start assembly! This went smoothly as well. It looked like a confusing array of tubes, but it quickly neatened up: we started by bolting together the inner part (“spokes”) for each of the six pentagons, which used up all 30 of the 65.6” tubes, and made things much more clear. We set the “top hat” pentagon to the side. For each of the five base course pentagons, we bolted in the A tube that went along the ground. Then we attached the first two pentagons by making it’s the equilateral triangle of A pieces that joined them. Wow! So we simply proceeded around the rest of the base course in the same way.

Once the base course was in place, we only had five equilateral triangles and the top hat pentagon to go. This part was well up in the air, so we used step ladders and scaffolding.

Bottom line: We started at 7am on Saturday, and by 1pm we the done was finished!

We decorated the dome with a hanging light and some lights strands.

There’s one especially cool part of this for Pete: when he was 13, he helped his dad build a 33 foot diameter geodesic dome on their farm in Kentucky. It was made of 2x4’s and plywood, and covered with fiberglass for weatherproofing. We used this as a workshop downstairs, and a rec room upstairs, complete with ping pong table, pool table, and bean bags! There are a couple of pictures of that classic above, as well as the dome we built for this project.

Step 40: Apocalypse Survival Command Center, Spittoon Lagoon, SS Minnow, and Carving Station

Here are pictures of some of the non-animated decorations. Again, most of the materials were cast-offs from friends and businesses. They sure added to the ambience!

Step 41: Add Guests, Mix With Good Music, and Bake in the Enjoyment of the Party for Several Hours!