Brief
I was tasked with designing a cost effective, small scale, scale-able and sustainable agricultural product. This product could be a growing system or part of a growing system.
Growing Experiment
At the start of the growing experiment we were tasked with making seedling trays or similar planting containers for our seedlings. I used a card-like material to make little seedling holders.
Week 2: My growing experiment was a wild success as I managed to grow things I did not even intend to! Unfortunately I had to eradicate the vibrant orange substance due to health related safety concerns.
Week 3: After transferring my seedlings into a traditional growing tray made of a material which does not encourage fungal growth, my plants could be monitored and cared for safely. Initially the plants which seemed to have sprouted were the broccoli and spinach.
Week 4: I was pleased to see 3 of the chilli seeds showing themselves. The other seedlings were growing well. However to date no lettuce seedlings have appeared.
Conclusion: The growing experiment has taught me that growing from seeds is more difficult than I imagined. Less than half of my seedlings germinated and grew successfully.
Ideation Sketches:
Sketches:
UJ Growing Tunnels
Thought Process:
The thought process behind my design started on our tour of the UJ Growing tunnels. While viewing the largest tunnel I noticed the how red the soil was. Instinctively I knew this was not a good growing medium for vegetables. After further research I found that there are various reasons why red soil is not preferable when growing vegetables. It is high in iron oxides which give it the visible reddish colour, however red soil is typically low in nutrients which vegetables need to grow. Red soil also has bad aeration properties as the soil is usually very fine and therefore tightly packed. Furthermore, red soil usually consists largely of clay which has poor drainage properties. This is not preferable for growing.
After identifying and researching this problem I started thinking how this could be solved. Following the guidelines in the project brief meant the system would need to cost effective, scalable and most importantly sustainable. Therefore simply buying soil would not be a good way to solve this issue. I then referred back to a system which I am very passionate about, permaculture. In permaculture, everything is designed to be a closed system or as close to a closed system as possible. Permaculture does in fact have a solution to this issue, composting. However permaculture does not have a solution to composting effectively at a very large university.
This is where I realised there was a need for a system to be designed making use of the available resources. The university has thousands of students, of which several hundred live on campus in residences. These students regularly make their own food. However the organic waste from making food is simply discarded with all other waste material. Students also frequently use paper regardless of the course they are studying. Some of this paper is recycled however the vast majority is thrown away.
The system I aim to design will be used by students at the university. I aim to achieve this by designing a system that is low maintenance and easy to use, so it can become part of daily life like recycling or doing laundry. The system must be able to fit in a small living space such as a residence room or apartment. It must not produce any harmful bacteria such as pathogens or any undesirable odours.
During my early research I found a documentary on YouTube showing an eco-apartment village in America where residents produced compost from their kitchen organic waste and used this in the communal vegetable garden to add nutrients to the soil for growing. They accomplished this by adding sawdust/woodchips which they produced from their garden clippings and refuse, to their compost bin inside their apartments. The wood material absorbed the moisture and odour produced by the green waste from the kitchen and added fibre to the compost produced. This type of system appealed to me due to its simplicity and ease of use. However as I applied thought over time I realised that getting sawdust/woodchips to each student would cost money and be a hassle.
Losing hope for my composting system, I was on YouTube one day when I stumbled on a video showing how to create compost using shredded paper. The video explained that both paper ad printer manufacturers are required by modern law to produce products that are non-toxic and environmentally friendly and partly bio degradable. The process of producing compost is to shred paper and add organic waste. Mixing these two ingredients and allowing them to compost produced a product similar to the woodchip and organic waste system I was initially investigating. However this system was perfect for University students who produce lots of paper waste from their studies.
I then started developing my design for a composting bin. One of the first challenges I ran into was how I would make a bin like structure for the system to be housed in. Rather that designing, prototyping and manufacturing my own bin I decided it would make a lot more sense to recycle or upcycle and existing product. After research and testing I decided due to their ability to hold a large amount of weight and being waterproof, that used 25l paint buckets were the perfect container to house the system.
Further concept development
Mixing Mechanism
Prototyping
I started making my prototype by designing and making a lid and bottom insert to house the mixing mechanism. Then designing and making a mixing mechanism using welding and various scrap metal. I am also in the process of prototyping a fixing mechanism to keep the lid closed. I also still need to make some prototype handles to operate the mixing mechanism with.
Engineering Drawing
Further prototyping, handle and clips
I started by making my handle, initially I planned on simply using flat-bar as I knew there would be lots available in the workshop. However I then found square tube which I decided to use as it was much more structurally sound. Next I had to develop a mechanism to easily attach and detach the handle so the lid can easily be removed. I achieved this by welding a piece of flat-bar onto the square tube and cutting a slot in the mixer's pipe. To secure the handle I drilled a hole through the pipe and the flat-bar to lock the handle in place.
Video of detachable handle
Photos of final prototype
Renders of 3D model
Final Engineering Drawing
Design analysis
After finishing my prototype I feel I should have spent more time refining the design of the mixing mechanism. Specifically by making more prototypes of the blade of the mixer. After some testing I feel the current mixer is not as effective as I would like it to be. Overall the finishing could also be improved. I attempted to source a polymer sheet for the inside where the mixer's bottom mounts, however I was unable to source a cost effective solution in time for hand in. The detachable handle is also not up to standard, however this is my own fault as I did a poor job cutting the slot in the pipe. I also feel I could have come up with a better design for the detaching mechanism. It feels very primitive to the user and could definitely be more refined. However I am still very happy with the concept I came up with. I feel it meets all the requirements of the project brief. Being sustainable, making use of recycled materials, cost effective and scalable as the lid and mixer can be scaled to any size paint bucket.
Costing:
Further Developement:
I designed a new hinged access door for the system
Adding door to model with custom hinge
Designing and adding the mechanism to attach the lid
Developing a new mixer as the one in the physical prototype was not performing as expected
Futher development of the handle for the mixing mechanism. As this is the most interacted with component of the mixer, it is crucial that it is ergonomic and easy to operate.
