Context
During a visit to Maroua in northern Cameroon, I observed local farmers manually unwrapping
beans—a process so slow and labor-intensive that it severely limited production efficiency.
This firsthand encounter with traditional agricultural methods sparked my decision to design
an automated solution addressing the needs of small and medium enterprises across Central
Africa.
Working independently over two months, I sought to develop my machine design competency while
creating a practical tool for communities facing these challenges. The project required
balancing technical performance goals—achieving over 85% yield, reducing operator physical
effort, and ensuring health and safety standards—with the reality of limited material
availability and the need for straightforward maintenance in rural settings.
Content
I led the entire research, ideation, and design process, developing competing prototypes
before selecting the final configuration based on raw material availability, parallel motor
positioning, and fan placement for optimal stability and reduced vibration. The shaft design
became critical—I engineered variable-dimension blades mounted at 120-degree intervals with
5cm spacing to ensure proper bean unwrapping without breaking, carefully calibrating
rotation speed against the motor's driving force.
Power transmission employed a double-groove pulley system connecting motor, shaft, and fan to
partition driving force efficiently. When the specified 1.1kW motor proved unavailable, I
adapted the design for an alternative motor while maintaining performance targets. I
prioritized compact assembly through flexible CAD modeling, positioning the pulley and belt
externally for easy interchangeability and providing direct shaft access for refinement and
repair. Steel thickness selection balanced structural integrity against overall machine
weight, a decision crucial for the portability farmers required.
Conclusion
This project fundamentally shaped my understanding of design for constrained environments.
Working with Nepitimbaye, Grace, and Tatsinda taught me that technical excellence must
accommodate real-world unpredictability—their perspectives on material substitution and
component failure modes proved invaluable when ideal specifications couldn't be met.
I learned a crucial lesson in team dynamics: as the project evolved from solo design to
collaborative implementation, I discovered that the effort invested in communication and
skill-building pays compounding dividends. Initially, I defaulted to executing small tasks
myself rather than spending time explaining requirements. However, once I committed to
thorough onboarding, the team operated increasingly autonomously, extrapolating from base
principles to solve problems independently. This experience reinforced that "doing it
yourself" is rarely optimal—setting teammates up for success through clear communication and
patient teaching yields far better outcomes than shouldering every responsibility alone.
