Today I made my own version of a coupled pendulum drawing machine that I saw on youtube (here). Here’s what I managed to produce:
And here’s a video of the thing working (from my Instagram):
Here’s a poorly drawn diagram of the setup:
I used water bottles as weights and twine as the string.I wasn’t very careful at all about the setup being symmetrical. In my setup, the weights hung about 5ft down and around 6ft apart. I got very small images, but I think I can fix that next time. I also didn’t experiment much with varying the weight or lengths of the pendulums.
I didn’t get very big or very clean images yet. But I learned a lot, and I’ll try again soon. A few things I learned are: (1) it seems to work best when paper is not against a hard surface (which means using a pen that doesn’t need to push against the paper too hard to make a mark – I used a felt-tipped pen); (2) to make bigger drawings, the strings and cup connecting the two pendulums should be attached closer to the weights; (3) the weights really need to be able to swing in all directions, so you can’t do this against a wall, you need them to hang freely in the air.