LEDs on a String

Okay, so a friend and I got bored and decided to play with this idea. We attached a few leds to some thin string (we used dental floss), creating a pendulum. Then we turned off the lights, pointed a camera up, opened the shutter for about 25 seconds and released the led:

A 25 second exposure of a single red led.

And then we tried making a double pendulum by adding a second, green, led.

And again, but with two leds to create a double pendulum.

Double pendulums are neat! They’re incredibly complex despite their simple construction, but can be correctly modelled with math.

Here’s our setup for the double pendulum. And remember, if you decide to try this, use a resistor in series with each led.

The double pendulum with the lights on.