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As part of my senior thesis in Mechanical Engineering, I embarked on a mission to address a persistent challenge faced by small-scale farmers in Kenya: the inefficiencies of post-harvest maize shelling. 

Maize, a cornerstone of Kenya’s agricultural economy and a staple food for millions, plays a dual role as both sustenance and livelihood. Yet, for many farmers, the process of shelling—removing kernels from the cob—remains an arduous bottleneck in the maize production cycle.

Shelling maize by hand is not only physically exhausting but also incredibly time-consuming, requiring approximately 9 hours to process a single bag of maize. While mechanized shellers offer a faster alternative—taking just 10 minutes per bag—they come with their own set of challenges. These devices are bulky, stationary, and require farmers to transport their cobs to shelling locations, often incurring steep transport costs. For instance, transporting just one bag of cobs can cost up to 300 KES (Kenyan Shilling), which eats away at 89% of the average profit per bag. These inefficiencies create a significant barrier for farmers trying to sustain a viable livelihood.

Recognizing the need for an affordable, portable, and effective solution, I spent the fall semester designing and building an initial prototype of a portable maize sheller. This January, with the support of the Harvard Center for International Development, I traveled to Migori County, a maize-producing region in Kenya, to test my prototype and gather user feedback. My goal was simple but ambitious: to understand firsthand farmers’ pain points and refine my design to better meet their needs.

Insights from the Field: Trials, Breakdowns, and Breakthroughs

My time in Migori County was a whirlwind of challenges, discoveries, and deeply rewarding interactions. I visited numerous farms, where I observed shelling practices and conducted interviews and demonstrations. Watching the labor-intensive process of manual shelling reinforced the urgency of developing a portable sheller that could alleviate this burden. When I demonstrated my prototype, farmers were intrigued and eager to try it, offering both praise as well as constructive criticism.

However, the journey was not without its obstacles. Managing farmers’ expectations proved to be one of the biggest challenges. Many were so excited about the sheller that they hoped it would be ready for immediate use. Explaining that this was an early prototype and that gathering feedback was a crucial step in the design process, required careful communication. 

Another unexpected challenge arose from the materials used in the prototype. To make it portable for travel, I built the sheller with lightweight, less durable materials. This unfortunately led to two instances where it broke during testing. These moments tested my adaptability, as I had to repair the device on-site to continue the interviews. While initially frustrating, these breakdowns provided invaluable lessons about the design’s weak points and opportunities for improvement.

Among all the interactions, one moment stood out vividly. During my final interview, I met a farmer who was particularly excited to try the sheller. As he operated the device, his enthusiasm was palpable. He pulled out his phone and recorded himself using it, narrating the process as if to share the innovation with others. His amazement at the design and his genuine excitement left a lasting impression on me. It was a powerful reminder of the impact engineering solutions can have when they resonate with the people they’re designed to serve.