Marble Launcher

Problem + Constraints

• Design a mechanical desktop perpetual marble launcher
• Must use rotary motion input + spring reset.
• Strict material constraints (acrylic, plywood, 3D print).

Inspiration + Research

• Pinball machine (high-velocity launch, track behavior).
• Magnetic loop launcher (airtime + return via ramp).
• Stanford Dish (funnel geometry inspiration).

Ideation + Sketching

• Generated multiple concept sketches.
• Focused on exploring mechanism possibilities.
• Goal: maximize idea quantity before narrowing down.

Prototyping + Testing

Ball Displacement Mechanism

• Tested slot shapes (circle, oval, triangle, square).

• Circular slot performed best.

• Used metrics of success (did it travel 180° smoothly?).

Funnel

• Tested angles (90°, 75°, 60°, 45°, 30°).

• Chose 60° for best alignment + manufacturability.

Bad funnel angle: balls block each other

• Considered 3D printing constraints.

Low fidelity prototype

Spring Integration

• Tested attachment locations.
• Found optimal slot for linear stretch + max extension.
• Incorporated hard stops.

Launch Hammer

• Iterated block width (.35 → .6 in).
• Identified consistency issue → redesigned.

Higher fidelity prototype

Iteration + Adjustments

Final Assembly + Documentation

• Final working version.

• CAD model.

Takeaways

• Break problems into subcomponents.
• Precision is critical.
• Plan before lab work.
• Ambition increased challenge but increased reward.