Pendulums

[sensesurfer]

Someone on a Burning Man mailing list posted a link to a youtube video called Pendulum Waves. The moment I saw it I just had to build it, but bigger and with blinky lights. I spent a few days doing experiments making pendulum bobs out of free weights and quickly realized that they needed to be aerodynamic and dense. Last week I made a mold and

Comments

[infinitehotel]

Holy shit, that's going to be cool! (The video alone is enough to make we want to skip work and head over to the shop...)

What's your plan for the cocking mechanism? (The board they're using in the video?) And do they have sensors for knowing relative position (for the synchronization?)

I miss the hell out of you guys; there's not a lot of this kind of stuff going on down here. :)

[sensesurfer]

We will have tilt switches to determine position.

I'm planning on using a cable that attaches to a pin for each pendulum. Yank the cable and release all at once.

Using a board and having people under them would be deadly as they weigh nearly 40lbs each.

[starphire]

When you say all at once, do you mean that yanking the cable a few inches or so simultaneously tugs on some kind of release mechanism, or do you have to pull 32 feet of cable to release the whole thing?

[sensesurfer]

2-3" pull

[perspicuity]

is there some kind of magnetic kicker to keep that going?

#

[sensesurfer]

nope it will need to be reset after 6-10 minutes

[sensesurfer]

I do have an idea to do this with fire instead of leds..... for that one the fire would be the kicker

[starphire]

No, but I think if this was done on a smaller scale, they absolutely should have that.

[lioritgioret]

This is beautiful, and it will be crazed and magnificent in lights.
I kept thinking it needed some kind of musical/chime element, too. If you are going to have radioactiverich program the lights to blink in sync with the movement of the pendulums, could you program synchronized chime-tones, too? Watching it just set off some kind of music-theory synesthesia in me, I felt like I could hear the pendulums as notes making chords and stuff depending on position.
Anyway, beautiful beautiful beautiful.

[sensesurfer]

Still thinking about this.... needs to add minimal wind resistance, but thinking of tuned pipes........

[lioritgioret]

Yeah, tuned pipes is kind of what I was thinking, but it might be way too complicated, especially the resistance. But cool.

[achinhibitor]

And of course adjust the periods to form a series of multiples of a fundamental frequency.

You'll probably need to be able to fine-adjust the frequency of each pendulum. E.g., if the frequencies are accurate to 0.01 Hz, they'll desynchronize after 100 sec. Hmmm, the circular correction to the simple pendulum period formula will be relevant, and maybe even thermal expansion.

[sensesurfer]

We will have switches that can measure the inaccuracy so software should be able to give us corrections.

[whitebird]

Buh.

I love artistic geeks! :)