Introduction: Genesis Cube - Advanced Plant Habitat
We are entering this in the professional category of the Growing Beyond Earth Contest. My name is Jeremy Stevens and I run a small machine shop that usually specializes in machine repair and replacement components. My contest partner Robert Dillard runs a small printer farm.
When we saw this challenge on instructables we knew it would be a good opportunity to practice prototyping and test our engineering abilities. We want this instructable to be not only about how we assembled the project but also how we went through the development process.
Total time ~500 hours
Nuts, Bolts and Screws
LED Grow Light Strips
Step 1: Research and Development
We began by researching currently available hydroponic systems, as well as the current system NASA is using. There are several systems that plants grow around a central light source, systems such as the “Omega Garden” and “Vertical Coliseums”. Most of these style units use Rockwool blocks that aren't reusable so a DWC (Deep Water Culture) or Medialess hydroponics was the best choice, but how do we turn that into a rotational system. Through our research we found Oxygenation in the root zone is key to the uptake of nutrients and prevents anaerobic bacteria. We came to the conclusion that an air feed drip trays rotating around a light source would be our solution.
We always begin designs on paper before we would transition to CAD. Where you don't have to worry about dimensions or any specifics just to get a visualization of how the system would work.
We developed our design to take advantage of readily available materials. Structural aluminum angle and flat stock was used for the long frame sides. We employed riveting these aluminum pieces to 3D Printed parts for the structure.The vertices for the central Trommel as well as other more complex shaped part we decided to 3D Print.
Once we got a solid idea of the form and function of or design we went to CAD and laid out our dimensions and tolerances. We also played with scaling the design and how it would work with multiple units being perpetuated with a germination unit.
We rendered a complete 3D model and 3D Printed a 1⁄5 scale miniature of the design. This process really helped with how it would be assembled and operate.
Step 2: Printing, Milling and Drilling.
The frame rails were drilled on the ends where they mate to their corresponding brackets.
The corners were riveted on one section then bolted so it can be disassembled into a smaller cross section for transport.
We 3D Printed a test tray section. Three sections make up a full tray. There will be 16 trays for a total of 96 sites . The air powered drip concept is similar to General Hydroponics " Water Farm" with a different implementation. In testing we were able to achieve 400 ml/hr with a 2 watt air pump. Some small revisions would increase its efficiency to save power for the watering cycle and its effectiveness in microgravity. Air is pumped through and pushes water to the tray. In microgravity the air would be pumped into the reservoir through a manifold directly displacing the water while trapping air within the water droplets.
The mesh tray inserts for the root system was generated by Prusa’s Gyroid Infill with no perimeters and top layers. We decided that this would provide exponential surface area for water to cling to in a microgravity environment. This will take advantage of the exaggerated effect of water's surface tension in low gravity while maintaining oxygenation without restricting root growth.
This combined with the rotation of the system will keep water from rotting the root crown.
Step 3: Mock Up and Assembly.
We placed the nutrient reservoirs in the bottom corners of the unit. An air duct tube runs in the upper left corner to circulate air. All electrical will be routed in corners of the frame rails . The air drip line will run through the back Trommel spindle and through the belt pulley. O rings inside the pulleys shank will allow it to seal while rotating with the Trommel This will keep the the water drip lines from snagging on any of the mechanism.
Step 4: Programming and Testing
We used a DHT11. A else if else statements allowed us to trigger the fan relay for temperature and humidity. The fan triggers off both variables. Over temperature and over humidity are set in the code but I think an adjustment knob will be added as well regular interval for general circulation. A real time clock module will help accurately coordinate the light and watering cycles.
The ultimate goal is to combine multiple units with a germination unit. Task scheduling a robotic arm or dedicated harvester to remove and process the trays in four week intervals. With fully implemented automation this system and scaled up versions could provide a steady output with little if any human interaction. This system could provide leafy greens. A scaled up versions could provide vegetables and fruits. Slight modification to the tray design and tubers such as potatoes could be grown. Thank you NASA and Fairchild Gardens for the awesome contest and opportunity so we makers can show our creativity.
Participated in the
Growing Beyond Earth Maker Contest