Polarity
Polarity, a kinetic sculpture by David Liu and Grace Liu.
Polarity is a tabletop kinetic sculpture that brings yin-yang, the eternal cycle of opposites, to life through motion and light. It reminds us that it’s not sameness, but contrast, that gives life its rhythm, emotion and depth. Illustrated by Grace Liu and translated into structure, motion and lighting animation by David Liu.
Exhibitions
- 2024 • Burning Man, Playasophy Camp (3:00 & B)
Lighting Sequences
- Sunlight/moonlight
- Lightning
- Sunrise to sunset cycle
Materials & Design
- Laser-cut plywood
- SK6812 addressable warm white LEDs
- PixelBlaze V3 Pico controller
- DC motor, capsule slip ring, bearings, 3D-printed pulleys, counterweight holder, and nickels used as balancing weights
At Burning Man 2024
Build notes
Mechanics: power and data through continuous rotation
The most complex and challenging part of the mechanics was figuring out how to get power and data to the LEDs on the rotating body.
A simple hack would be to put a battery and LED controller on the wheel. I didn’t want a battery at all, though. Instead, I opted to use a slip ring to get electrical power/data through a 360 degree continuous rotation.
I found micro capsule slip rings on Amazon and Adafruit but very little material about how to incorporate them mechanically. The rotor has no body to grip or mount anything onto, and the flange on the stator is confusing. (I’d still like to see other applications to understand the intended usage.)
After a lot of head scratching I came up with a design that embeds the slip ring into a 3D printed hollow drive shaft. The wires on the stator side of the slip ring exit through a slit in the shaft.
The shaft itself has two flat faces so that it can be driven by a pulley and belt.