Designed and built, in a 4-day sprint, a motorized cable system that flew a giant hot-air balloon across the fraternity house for Homecoming. Won Best Mechanical Pomp.

Built for Georgia Tech Delta Chi’s “Wizard of Oz” Homecoming display in a 4-day sprint (about 40 hours). The system animated a large chicken-wire hot air balloon so it traveled autonomously across the house façade, on a custom support structure that couldn’t modify the building.

Mechanical design

• Gravity-fed carriage: the balloon travels down an inclined line under gravity, then a motor retracts it.
• Applied deformable bodies and machine design principles to a cantilevered wooden support structure, with zero structural modification to the building.

Rapid prototyping

• 3D printed custom mounts for the motor and Arduino.
• The first 3D-printed spool deformed under high torque. Redesigned it with a heat-set insert and set screw to spread the load on the shaft, which solved the problem.

Mechatronics

• Selected a high-torque geared DC motor from hand calculations of weight and friction.
• Wrote C++ on an Arduino to manage timing loops, winding duration, and release cycles.

Result

The balloon cycled reliably throughout the event, and the display won the Best Mechanical Pomp award.