The concept behind the sculpture is fairly simple. Each set of petals is attached to a roller, and each roller pushes on the next to synchronize the motion. The secret is the slight offset between each roller, such that each is out of phase. This prevents the petals from colliding as they pass through the center. It also generates the spiraling motion. Depending on the phase shift, the pattern changes significantly.

I chose 19 rollers since it fit nicely on an 8in circular hoop. I settled on a 7° phase shift between rollers, which gave a nice spiral pattern without too much overlap. The first roller is driven through a set of bevel gears attached to a small motor. Each roller is 3D printed, and contains 4 stems. Each stem is a piece of 3/32in stainless welding wire. On the end of each stem is a 3D printed petal, which on both dies is covered in holographic vinyl.

The base of the sculpture features a ring of LEDs with a diffuser on top. An arduino nano runs the LEDs, and switches a relay to drive the motor. The whole system is driven off of 5V USB power.

The design totals 76 individual petals and stems, and 152 vinyl stickers.

The most important part of the sculpture is the motion, so it was critical to test the rollers as early as possible. Each roller was printed out of Markforged Onyx, and then the forks and rollers were superglued in to their designated holes.

The small 5V motors I had struggled to overcome the friction of the rollers and drive rods in one specific spot: As the drive rods turned towards the center of the hoop, the friction greatly increased, and the motion slows down.

I tried a miniature stepper motor as well, thinking that maybe this could give me more uniform motion. However, the stepper also did not have enough torque to drive the motion.

Eventually I determined that the friction was due to the drive rod binding between the forks. By removing one side of the fork, I could greatly reduce the friction. This constrains the motion to now only work in one direction, which is not a problem for the motor driven sculpture as opposed to a wind driven sculpture. Additionally, I alternated the side on which the drive rods push, which means that only half of them will be pointed towards the center at any given time. This also helps even out the friction across the motion.