Thursday, July 31, 2014

LED Lettuce, The HydroTower And LED Humboldt Hydroponics

Tonight's blog post has two tales of LED grow lights and the planting of a seed for a future collaborative project in the Humboldt Microcontrollers Group.
LED lettuce (from

On July 11, Wired had an article titled, "LED-lit indoor farm produces 10,000 lettuces a day." Because several members of the Humboldt Microcontrollers Group have expressed an interest in using microcontrollers (MCUs) for automated or indoor plant growing, the 'LED lettuce' article caught my interest. The Wired article presents some pretty impressive statistics.
"A newly opened indoor farm in Japan has been built with LEDs that emit light at wavelengths optimal for plant growth...It's 2,300 square metres, making it the world's largest LED-illuminated indoor farm, and is already producing 10,000 heads of lettuce per day. The LED lamps allow Shimamura to adjust the day-night cycle for the plants, allowing them to photosynthesise during the day and respire at night. Discarded produce is cut from 50 percent of the harvest on a conventional farm to ten percent, and the lettuces grow two and a half time faster...stringent climate control means that water usage is just one percent of the amount needed by outdoor fields."
I can understand that the indoor growing and carefully controlled ambient conditions would reduce the amount of water to grow plants compared to outdoors. But it seems a real stretch to believe that the LED lettuce farm only uses 1% of what would be used for an outdoor lettuce farm!

Calvin students HydroTower workshop area
The second LED grow light project took place in my hometown -- Grand Rapids, Michigan. That project was the HydroTower, the senior design project for a group of Calvin College students. The HydroTower was a fully automated hydroponic garden for home use, using an MCU for control and LED lights to enable photosynthesis and plant growth. This MCU / LED grow project popped up in a Google search after I read the LED lettuce article. Since the HydroTower happened in Grand Rapids, it seemed appropriate to find out a little more. The Calvin College alumni 'magazine' Spark says this about the HydroTower:
"In October, the team researched hydroponics, learning about the floating, misting, and flood-and-drain (ebb-and-flow) methods of growing...their HydroTower would be constructed of a 20-by-32-by-32 inch base unit, to house the electronics and plumbing, and two open growing levels, each measuring 24 by 32 by 32 inches. The unit would operate on an ebb-and-flow system, and it would irrigate the plants and dispense nutrients automatically...In November, Team HydroTower broke the project into components, and each student engineer took one. DeKock would construct the
HydroTower is finished
tower. Kirkman would engineer the water and piping. Vonk would create the LED system, using only red and blue lights because those are the only colors of the spectrum that plants absorb. Meyer would program the microcontroller that controls the LED lighting, the pump and valves, and the touch-screen user interface. And Eelkema would create the pH and electroconductivity sensors that handle nutrient control—a system, the team emphasized, that sets HydroTower apart from other hydroponic farms. “The sensors would input into a microcontroller, which would then use algorithms to decide which nutrients need to be replenished,” Eelkema explained. “The only problem with that is the biology and chemistry research is far more advanced than we have time to cover. Right now I am shooting for a best guess that I know won’t kill the plants
The Calvin College students' project website gives this final update on the project:
"All through April and the first week of May Team HydroTower finish the prototype. The month of April saw the addition of our second growing level and some new plants. Other major accomplishments made before Design Night were completion of the pH and EC sensors, a working User Interface on the touchscreen...On May 7th the Engineering department held their annual Senior Design Open House where the team answered questions and took comments about the HydroTower. Later that evening the team gave a presentation detailing some of the work and challenges they faced during the past year...HydroTower is a finalist in the IEEE President's Change the World Competition. The project has been selected as one of 15 finalist entries and the top three winners will be announced at the end of May."
Humboldt Laser Harp v.1.0 nearly finished
It seems like the first collaborative project from the Humboldt Microcontrollers Group, the Humboldt Laser Harp v.1.0 (HLH), is well under way. Ed Smith said today that the HLH was being played by his kids in his kitchen. We will no doubt be working on improvements to HLH v.1.0, and at some point will start planning for v.2.0.

But this seems like a good time to plant a seed for another MCU group project. And a project involving some type of hydroponics and LEDs seems like a good target. I'll be reaching out to a few people to see if they want to work on that kind of a project. If you're interested in being involved with an MCU / LED garden project, contact me at arcatabob (at) gmail {dott} com.


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