This is the post where I was supposed to lay out my killer project...well, this is half of it. The post got pretty long so I decided to split it into the two distinct phases of the project.
This is the project I had been looking forward to building for months.
I knew I wanted to do something with a coffin. I didn't know what, but I had always wanted to build an old-style toe pincher coffin. Some quick size estimates in hand, I ran down to the hardware store and picked up a stack of 6" fencing slats (cheapest I could find was $2 a board...wood fencing is pretty rare in the desert). I'm not a carpenter by any stretch of the imagination, so I was kind of making this part up as I went--as you all with any kind of wood skills will quickly see.
My strategy was as simple as it gets: lay the boards out, draw the lid to fit around an adult, snap a chalk line, cut, and screw together. Lay the lid across antother section of boards, outline, cut, screw. Figure out how deep to make it, cut some boards, screw them together. Dead simple and inelegant (and it shows in the quality, but I wasn't concerned...the rougher it looked the better the illusion, I figured. I wouldn't repeat that strategy for something I was going to sell or display in the house). The end result looked passable and seemed fairly sturdy.
Next question was: what to put in it? I had wanted to do some kind of automation, possibly either a skull kit with movement on 3 axes (as pretty much mastered by the guys over at graveyardskulls.com), or possibly a Monster In a Box (where a closed box shakes or the lid moves or some other movement that alludes to something nasty inside that wants out). The big problem ended up being that due to the tenuous state of my employment, I had to cut my budget wa-a-ay back for this Halloween. So, the three axis skull was out. Maybe next year.
Short version of the MIAB: I went too cheap, experimented, and failed miserably. My plan was to rig a motor and gear--a hand held drill, fairly commonly used for these I was told--and a motion detector so that once a guest approached, the motor would spin and the lid would open and close. And oh, did it ever. Holy crap.
Lesson 1: if you use a drill from a pawn shop, spend the extra $5 for variable speed. My mechanism worked great in testing, but the problem was that the motor spun so fast that it literally started to tear the coffin apart within seconds. Even after more reinforcing with cross braces, gorilla glue, and more screws and brackets, the result was the same. It wasn't going to last more than a few minutes before falling apart.
Lesson 2: a drill isn't the best solution for this, variable speed or not (I hooked an off the shelf rheostat--the kind you would use to dim your house lights with a rotary switch--onto the power cable, and it wouldn't even turn on). I asked some of the very cool folks at halloweenforum.com for help, and many of the responses said that a wiper motor was the way to go; a drill is going to have trouble with that kind of weight load, and at slower speeds loses a lot of it's power, meaning less strength to open the lid and more potential problems. You can buy a speed regulator (kind of like a rheostat but designed for power tools like drills and routers), but they start at about $20.
So, then, the question became: spend more money on a power regulator and hope that it would still be able to lift the heavy lid, buy and mount a wiper motor and 12V converter along with the proper gears and levers, or go cheap and pull together a sufficiently disturbing static prop. Finances being tight, I opted for the latter.
All was not lost. I combined two projects into one and made something that I think it pretty cool for a static prop.