I’ve been working on a series of automated “drawings” that react to local viewer movements by tapping on the glass used to frame them. The apparatus for this one looks a bit jury-rigged at the moment, but it’s coming along.

Now and then the prototypes give up something interesting, as this did when I decided to drive a wire armature at slightly four times its resonant frequency and used a jar lid in place of the glass. Might be useful.

The stereo flac file has the lid pattern on the left channel with the driver (electromagnet) pulse on the right. The driver beat varies +/-10ms or so thanks to the method used to adjust the frequency, but averages to 153.85 bpm over the 3’40” length of the sample.