Design Problem

Kenya is a very variable country regarding climate and farming conditions and requires severe determination to break even when farming. One of the major challenges faced by subsistence farmers is droughts. I aim to create a device that will facilitate the planting of subsistence crops and various types of trees. Easing the workload of the average subsistence farmer is something that would improve the livelihood stability and mental health of many farmers. This device would make the lives of poorer, small-scale farmers easier and would ensure more rapid planting sessions. Such planting would make subsistence farmers more efficient and lower the hours that they would have to work. This, in turn, could increase successful crop yields in Kenya, easing the strain on the food supply chain. The product would affect 2 main categories of people: Farmers in western and southwestern Kenya and NGOs who wish to plant trees on a larger scale, like fencing, tree restoration, and cash tree farming. The product would ideally be able to facilitate the planting of the following crops and trees:

  • Beans
  • Tomatoes
  • Mukau Tree (Furniture, Construction), Winter Thorn (Crop Yields, Shade), Calliandra Calothyrsus (Crop Yields, Soil Fertility, Shade), Moringa Oleifera (Drought Resistance, Medicine), Grevillea Robusta (Crop Yields, Soil Fertility, Water Infiltration), Azadiratcha Indica (Pesticide, Fertiliser, Soil Fertility), Markhamia Lutea (Soil Fertility)

Design Process

This project utilised the Design Cycle pictured below to develop models and prototypes for fulfilling the objective.

The Inquire phase involved research both online and then through real-world testing of the speed of typical seed planting methods. The development phase involved solo and team brainstorming with several peers and teachers, as well as communication with a seed planting and distribution professional named Teddy Kinyanjui. He founded Seedballs Kenya and gave the following advice:

  1. Consider the weight of such a tool – planting 10 seeds might be perfectly fine, but how would the same implement feel after 8 hours of work?
  2. Consider the cultural taboos around disturbing the soil in some of the regions the initiative targets – Northern Kenyans see it as disrespectful to the soil and consist almost entirely of pastoralists. Instead, perhaps target companies dedicated to reforestation with this device.

The create and evaluate phases simply followed an iterative model. Initially, the project aimed to fulfil the objective by creating a hollow hoe containing seeds within the shaft that would be released through a catch mechanism. This phase of the project underwent 4 iterations before being abandoned. It was abandoned because of complications in the procurement of the materials, as well as an inability to procure a hollow shaft both light and strong enough to fulfil Teddy’s advice. The various models are pictured below.

Following this failure, it was decided to attempt the creation of an attachment that would serve the same function utilising a slightly altered method. The brainstorming is pictured below, but consists of an idea to create an outer PVC or plastic pipe with a hole surrounding a longer, inner pipe with the same sized hole, offset lengthwise by the diameter of the hole, would serve as a sealed containment for the seeds, and a strip of inner tubing (Henceforth Bladda) running around the back of the tubes would allow tension to keep the hole closed. When the longer central tube was pressed, the holes would align, allowing seeds to drop out, and then the bladda would push the holes back out of alignment once pressure was alleviated.

Gradual improvements over the first four designs were as follows:

  • Switching from PVC to 3D Printed plastic to allow for correct tolerances.
  • Switching the bladda tension from through-tube to behind-tube.
  • Changing attachment from bladda tie to screw in
  • Adding rails to the inner and outer tubes to align them to the holes

Afterwards, the following improvements were made to take Model 4 to Model 6:

  • Increasing the infill density to 100% to increase strength
  • Changing the front part of the attachment to prevent mud from getting in
  • Increasing the length of the attachment to add a third screw for stability.

Link to Process Journal and Final Reflection Video