Author Archives: Doug

Halloween 2009: Gigantic Floating Eyeballs

We gave out candy to 196 kids plus one father in a Rush concert shirt. A good night by anyone’s standard. And technologically, it was a thing of beauty.

I have to say that the start of the evening was looking grim. The wind had picked up. The whole rig was in danger of becoming a sail. My neighbor was still mocking me about the fantastic set of hooters I had constructed above the doorway. Then the sun went over the horizon and all was good.

The video screens lit up and the sound was turned on. It all just… worked. As if I had just gone out and bought the system at some yuppie Halloween superstore (something I was accused of several times).

The key thing here is, in fact, the sound. Yes the eyeballs have sound. No it doesn’t make any sense, but it’s just one of those things I’ve learned that everything must have a sound to have an identity. So I gave it a voice and you can hear it in the video below. The other thing I have learned is that there is no substitute for proper amplification. This year I employed the Roland KC-350 combo amp which made the house shake. It could be heard a block away. It made dogs howl.

Anyway, kids were truly mesmerized. I’m used to the parents wanting to take a second look, but children actually delayed their pursuit of sugar to stand and stare. There is no higher complement.

Thanks to all who dropped by. For those who couldn’t, this please enjoy the video. And don’t forget to turn the sound up.

Front of house
Closeup

Gigantic Floating Eyeballs, Part 4

Ruth was the first to suggest that the video screens looked like breasts. I didn’t see it, which is shocking, but I was focused on the end result and always had seen the screens with the image of an eye even when the projector is off. Now it is obvious: round and firm, yet supple with perfectly centered…

Enough of that. But the first thing my neighbor said when he saw them was “Going pornographic this year?” Now the pressure is really on. Even if I can get this thing to work, there is a chance that I will mistakenly crossover from scary to erotic.

One more thing to do: design and build the motion control system. I left this to the last minute since I work with software every day. The plan was to create a pseudo-random set of movements for the two pneumatic cylinders. Now I am out of time.

I was going to scrap the whole motion thing, but then it struck me that I don’t need software at all. Each input to the cylinders has their own speed control. If I just add a simple on/off timer, the cylinders can be set to move in and out at slightly different speeds, thus creating three dimensional motion. It looks like this:

Lift mechanism

I know… messy. But try to remember we are in panic mode. Time to put this thing up on the roof.

How to Assemble Your Gigantic Floating Eyeball Kit

Step 1: Place base (with lift mechanism) in desired location.

Step 1

Step 2: Attach center bar (with mounted projector) to base.

Step 2

Step 3: Attach video screen assembly to the front of bar.

Step 3

Step 4: Attach mirror assembly to the rear of bar.

Step 4

Step 5: Enjoy!

Gigantic Floating Eyeballs, Part 3

My first mechanical Halloween project was made out of PVC pipe. PVC is strong and easy to assemble because it can be glued together and there are ready-made elbows available that make angles easy.

There is a drawback to using pipe: It’s round. Inevitably you need to attach something flat to it. A flat surface screwed to a curved surface will wobble and wobbling is bad.

This brings us to the question, “How does one mount two large round surfaces to the end of a pole?” Well… like this:

Screens on supporting structure

I wish I could tell you that this was the result of years of experience in mechanical design or, better yet, computer aided design (as a throwback to ’90’s car commercials). The reality is that I started by attaching one piece of aluminum and it wobbled. So I attached another piece and it got stiffer. A dozen pieces later we have a nice rigid frame that can be attached to the end of a pole.

So, we’re done, right? No.

Remember the aforementioned mirror at the other end of the pole? The mirror assembly weighs about 15 lbs. The screens also weigh about 15 lbs. When you put one of each at the end of a 6 foot pole…?

That’s right. The pole twists. Especially if the pole is made out of aluminum. When the mirror moves the screen does not move with it. I’m screwed.

There are many solutions to this problem, most of which I have not the time or money to implement. What I do have is aircraft cable. The structure will either submit or destroy itself. Start the betting now.