I just completed a variant of the $300 MVP Food Computer. I encountered some challenges based on my design changes, and I encountered a few also because this is a new design that is still being perfected. It’s taken me about a month to gradually complete my build; I’ve taken photos and notes, and over the next couple of weeks I intend to document my progress to this point. The project sponsors have been extremely helpful with the issues I have encountered. You can review my questions and their answers here: $300 Food Computer.
My name is Dave, and I’m an amateur (ham) radio operator, holding a General class license. I have a Master’s degree in a non-STEM field. My coding knowledge is extremely limited, but I am handy with a soldiering iron, and I understand basic electrical and electronic theory.
I decided to build an MVP variant using a commercially produced metal shelving system. There were several reasons I decided to do this, despite the increased cost (the shelving unit runs around $80 at home improvement stores, compared to maybe $20 using PVC and a plywood piece for the top).
First, using the shelving allowed me to easily double the size of the chamber. I’m certain that you could increase the size using PVC pipe, but you’d probably have to add some cross members to support the additional weight.
Second, I am running this project in my basement, and I occasionally have mice come for a visit. Using the shelving allows me to have the grow chamber off the floor (yes, the mice can still climb it but it might be a challenge), and also having it off the floor helps stabilize the temperature, and the extra shelves provide me with space to store the consumables (fertilizer, PH adjuster, etc.) as well as a location for a monitor and peripherals if I need to access the Raspberry Pi directly.
And Third, I’m considering eventually adding an automatic pumping system (ebb and flow method), and having my grow chamber elevated will give me a gravity return for excess nutrient solution.
While I think it is possible to build the MVP at near the $300 cost as stated, be aware that variations, changes in availability of materials, and simple mistakes may increase your cost. I haven’t kept detailed records of costs associated with my build, but I estimate that I’m close to twice the project cost using the original design. Regardless of how you plan to complete this project, be aware that if you intend to keep your costs low, you may have to delay your build to obtain the lowest priced materials due to availability. Also remember the old adage of “Measure twice, cut once.” Visit the original $300 Food Computer thread and see the bill of materials here: $300 Food Computer.
So my first post is a wall of text. In a day or two I’ll continue to provide more details on the issues I encountered and/or methods I used to build my MVP variant and some thoughts that weren’t addressed in the instructions.