Thread: Dracula's Coffin

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---17 Feb 2011 ---
Tomorrow morning I'm starting a new project: Dracula's Coffin.
It will be a pneumatic powered prop controlled through a program written on my laptop.

Sequence of Operations:
> Start with a closed coffin on a table
> The lid to the coffin will slowly open (Cylinder #1 and Signal #1)
> Sound of a creaking door will be triggered
> Red LED lights will illuminate the interior of the coffin (Signal #2)
> Dracula's entire body will slowly float to an upright standing position (Cylinder #2, Signal #3)
> Dracula's arms will raise somewhat (Cylinder 3, Signal #4)
> Dracula's eyes will light up red (Signal #5)
> Wings behind Dracula will fold out and perform some slow flapping (Cylinder 4, Signal #6)
> Sounds of wings flapping will be triggered.
> A strobe light will possibly be engaged (Signal #7)
> After a given time the prop will reset back to square one.

Controller:
The control program has all ready been written and proof of concept has been verified (my December project). I've ordered a USB controlled I/O (input/output) board from company called Labotronik out of Canada:

This board is simply (8) relays which can be opened or closed from a CPU. It also features (8) inputs to allow for triggers or whatever.
I'm a little bit old school and have never learned JAVA or C++ or whatever is current these days, but any old logic will run this board. I actually used Fortran. Through a series of time delays and commands I can tell the relays to open and close on any sequence. By the way, this can be done with DMX, but I was choking on the investment required to get a DMX up and running. This board costs $49.00.

Pneumatics:
With the above completed, I'm on to the mechanics.
I've ordered and received (5) pneumatic kits and corresponding cylinders from Fright Props:

I have (4) 0.75" bore x 4" long double acting cylinders for the smaller items, and (1) larger 1.5" bore x 12" long cylinder to raise Dracula out of the coffin.

Base Frame:
I need to have a base below the coffin to house the pneumatics and the controllers. I used Google Sketch-Up to do some basic layouts.

This should give me enough room to house everything and give the appearance of a table just below the coffin. I will surround the perimeter of the base with a red skirt.

I'm using 1.5"x1.5"x0.125" angle frame. You should be able to pick it up from any metal supplier. Don't use Home Depot or any type of hardware store as they charge way too much for angle. I''ve also heard from someone on this site about getting bed frames from Goodwill which is a great idea. This frame could probably be made out of wood, but keep in mind there will be a lot of forces involved with pneumatic cylinders. If you are lifting 50 pounds the cylinder could easily be pushing 200 depending on your angles and leverage.

Start with the perimeter of the bottom of the base frame:

Some quick pointers:
1) Measure twice, cut once.
2) Spend as much time as you need to make your work square. Otherwise you will inherit multiple problems later.

Build two identical frames shown above. Cut your vertical members and tie it all together:



I added wheels to the bottom. Now on to the "lever". The lever will be the device that will lift Dracula to an upright position.
This lever will receive the highest stresses and forces so I'm taking time to make sure these joints are strong. The actuator
is rated for about 200 pounds of force so you can imagine how this might tear up the prop if I'm not careful. In the background
you can barely see the new cross member which has the hinges attached. The lever frame members are not yet attached
and are sitting on top for reference.



The lever frame has been assembled and is now standing upright.



Here is a detail of the hinge and lower lever. Again notice the triangular frame shape for strength.



Ok, the main actuator has been installed. Please take a lot of time to make sure the actuator fits in both the retracted and extended position. Make sure the actuator is pulling/pushing through the entire swing (if your not careful the actuator may have great force for half of the swing, but the angles change and all of a sudden the actuator is positioned incorrectly). Make sure your anchors for the actuators can handle the forces. Here is an image of the installed actuator.



And an image of an anchor joint.



This is where I sit today. I will update as I make progress.

Wow bamtunebam im loving this idea, thank you very much for making this a tutorial and not just a prop showcase, it's gonna be awesome, i'll be coming back to check for updates.
Thanks again
Phil

Wow! That's an ambitious project. I'm sure once I see yours completed I'll want to add to my vampire and coffin.
This is going to be a fun project to follow.

I've added to the tutorial above.
Included actual images of the base frame.

I applaud you for your ambition-- and it certainly looks like you have what it takes to pull it off-- best of luck!

Another update posted today.
I finished the lever to lift Dracula and also the actuator to lift him.

Great project. Definitely following along!

Bamtunebam, I'm writing this for the others, prob. you already know this. A man in the Halloween prop business told me when they began they made a coffin with a sitting-up body similair to this one. The first several times they tested it , it flunked!
It sat up So Fast that the head flew across their shop! (Breaking loose from the body.)
This would be a real unexpected effect for the audience but kind or basically unrepeatable on a timely schedule.
Pneumatic cylinders, "they" know not what they do! (So "we" have to)
You could have your favorite cylinder, be predictable, friendly for years, then one night it pops you in your "chops"..Your fault though.

Gym,

You are correct. I've been working this out in my head. My goal actually is to have a slow rising prop for more of a creepy effect. I've purchased flow regulators and flow limiters for each of my cylinders. With this much power I could quickly destroy the unit if it runs unregulated, or even destroy a guest, ouch!

My bigger worry is when Dracula lies back down. Gravity will be working with me and I don't want the unit to slam down. Again I will need a second flow restrictor for the exhaust port.

I hope to spell it all out when I start piping the pneumatics.

Awesome..I wish I could do this type of stuff..