Planetary Sun Mechanism

When rotated, the “sun petals” smoothly extend outward and retract back. The model was originally designed as a tactile control knob for a variable resistor (potentiometer) used in LED lighting systems.

⚙ How it works

Inside the model is a compact planetary gear system. Rotating the center disk drives the gears, which synchronously move the outer petals in and out.

🔧 Features

• Planetary gear mechanism

• Expanding/retracting “sun ray” petals

• Designed for potentiometer control (LED dimming)

• Fully 3D printable assembly

🖨 Print settings

• Material: ABS, PETG, PLA

• Nozzle: 0.4 mm

• Layer height: 0.2 mm (or similar)

• Infill: 15–25%

• Supports: Not required (depending on your printer tuning)

🛠 Assembly

• The model is designed as a multi-part assembly

• Gears and petals should move freely after printing

• Light sanding or lubrication may improve movement

• The center hole is intended for mounting on a potentiometer shaft

• The mechanism requires:

  • 10 petals

  • 2 linkage arms per petal

• As pivot pins, use pieces of 1.75 mm filament

• In the top cover, you may need to drill holes to fit the filament pins

• If you want the petals to open in the opposite direction, simply mirror the internal gear before printing

💡 Use cases

• LED brightness control knob

• Interactive decoration

• Educational demonstration of planetary gears

• Desk toy / fidget mechanism