122 Make: Volume 17. PROJECTS: beatbearing makezine.com/17/beatbearing.
Illus tration b y Tim Lillis. Making beats with balls the beatbearing plays rhythms ...
PROJECTS: beatbearing
makezine.com/17/beatbearing
Making Beats with Balls The BeatBearing plays rhythms based on ball bearing placement. 1
A 4×8 grid of transparent plastic acts as a control surface. The horizontal positions define a repeating musical measure with 8 beats, while the vertical positions carry 4 different preprogrammed drum sounds that you can trigger at each beat.
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The visualizer on the flat-screen CRT monitor shows which bearings are active and where the current beat is in the 8-beat sequence.
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A cache in the plastic base grid holds unused ball bearings.
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A plastic crate acts as a handy cradle for the monitor.
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A steel ball bearing in any grid position closes the electrical connection between the 2 halves of a split metal washer underneath.
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An Arduino microcontroller collects the ball/no ball states of each of the 32 washers and continuously sends this information to a laptop computer via USB cable.
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Two multiplexer chips let the Arduino read values from all 32 washer switches, receiving them in sequence through 2 analog input pins.
Make: Volume 17
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A laptop computer takes the rhythm feed from the Arduino and translates it simultaneously into both MIDI sound data and visuals for display on the screen underneath the grid. The laptop also runs standard software to convert the MIDI into sound.
