We now have an operationally testable system. Yay!!
Here’s where we are now:
- All the major components have been bought, or built, unit tested, and integrated into the system, except for the lights
- I don’t have the lights for the system yet. Just a few days ago, the container ship from China docked in Long Beach, CA, so I expect the lights to arrive shortly
- The system will ultimately have 3 plant towers, but towers 2 and 3 won’t be 3D printed and installed until tower 1 proves itself
- The lettuce factory has been moved from the workshop into its permanent home in the basement
- The plumbing and electrical systems tests were passed; only one tiny water leak had to be addressed.
- Temporary lights were installed so we can get started with operational testing
The next steps will be:
- Connect robot controller hardware to the relays in the wiring cabinet
- Write the Lettuce Factory robot software, install it on the hardware, and test it
- Load the factory with nutrient solution and turn it on, and start the Factory control robot
- Move all the plants from the germination tank to their respective sockets on Factory Tower 1
- Install the new lights when they arrive
The Story in Pictures
Here are a few pix that tell the story of construction and installation. Then there’s a few pix about how the system actually works, with extra detail about the key components. Finally we take a look at what it’ll take to begin operations, and how the system will be connected to the robot that will control it.
Useful Operations Data
The aerator pump only uses 8 watts, but runs constantly. You can barely hear it run.
The nutrient pump is a half horsepower pump. It uses about 400 watts when running, and it takes about 30 seconds to move the 6 gallons of nutrient solution from the reservoir tank up to the gravity tank
With just one tower operational, it takes about 18.5 minutes to drain the gravity tank through the tower and back to the nutrient tank.
When I write the control robot, I’ll use this operational data. The design of the robot has to address:
- number of operational towers
- flow rate of nutrient through each tower
- target time interval between nutrient solution applications
- how long it will take to drain the gravity tank based on the number of operational towers
As I mentioned above, the next major tasks are to connect the controlling computer to the lettuce factory, then write the software that will control the factory, and then load up the tower with new plants, and start operations. I’ll use temporary lights until the new ones arrive, whereupon they’ll get installed. That will be very exciting!
Next Progress Report
I’ll produce another progress report as soon as sufficient tasks are accomplished to warrant it. I expect that’ll be in late March 2023.
3 thoughts on “Hydroponics: Progress Report 25-Feb-2023”
This is a wonderful project; thank you for these reports!
A thought re: lighting:
reproducing the fluence of sunlight with electricity is kind of expensive. Over time, the cost might justify setting up an outdoor illumination arrangement for use on days with no risk of rain. Provided that the plants can tolerate it, you could increase the effective light intensity by placing a flat reflective surface horizontally to the south of the setup, and a vertical reflective surface to the north. This would provide some (depending on how reflective the surfaces are) back-side illumination and would increase the front-side illumination. OTOH, the light exposure might degrade the polymer components over time, and it would be necessary to acclimate the plants to the increased exposure.
Consider incorporating red lettuce in your plants mix; I’m especially fond of the variety “Merlot”, which gets a deep burgundy (under sunlight; my LED-lit indoor starts are much paler). Red lettuces have loads of antioxidant phytonutrients.
I’ll continue to follow this project with great interest.
Artificial light is indeed expensive. I expect the lights I’ve bought to use around 400 watts collectively, and they’ll be on 12+ hours a day (not sure what the optimum daylength for lettuce is yet).
As you know from the report, I have a greenhouse, and I expect to adapt and extend this system for use in the gh. I thought I’d use the basement/household scale system to do some learning before I scale it up. Gh ops have some issues, too, and the gh will have to get some improvements – ventilation and heat management in particular – before it’s ready for prime-time. This has been the subject of considerable thinking and component development over the past few years, and I’m nearly ready to commence construction.
That said, my expected design is a bit complex, and uses some expensive (for me) inputs, so it’ll take me a few months to wind into that work. But this design I have in mind addresses a lot of the key issues of greenhouses (bleed energy, big variances in temp and rel humidity, etc.).
And all your suggestions about light management (reflectors, etc.) are right on-point. Hopefully, we’ll get a chance to discuss those ideas, as I think my designs will benefit from a 2nd pair of eyes.
I’ll see if I can’t find Merlot seeds and get some started right now. Pls provide a link to a source if you get a sec.
As I mentioned over @ NC, the next big thing is to get the germination system up to snuff; what I have is really bad right now, and all of a sudden, I need a lot of new seedlings, pronto.
Samuel: I found plenty of sources for Merlot lettuce. Ordering today.