One reason we really like [Rulof]’s hacks is that he combines the most unlikely things to create something unexpected. This time he makes a fast-moving loop of cotton string undulate in time to music.
To do this he uses cotton string, hard drive parts, two wheels from a toy Ferrari, two DC motors, a plastic straw, a speaker, and an amplifier. The loop of string sits in the air by being rapidly rotated in between the two wheels. The hard drive parts, driven by the amplifier, give the string a tap with an amplitude, and at a time determined by the music. The result is music made visible in the air in front of you, or in his living room in this case. Check out how he made it, and see it in action in the video below the break.
And if you want to see more of [Rulof]’s creations, have a look at his leg mounted, underwater, beer bottle propulsion system, his vibrating gaming chair, and another usage of the same hard drive parts but this time to make a microphone that works surprisingly well.