Welcome to installment number seven of my new weekly series, the Design Challenge Project Summary. Just like the three previously featured projects, this week’s featured project is from the Vertical Farming Design Challenge, and is one of my favorites from the challenge. The Vertical Hydroponic Farm by James O'Donnell (jamesod) is one of the most frequently updated blogs of this challenge.

 

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The goal of Project: Vertical Hydroponic Farm, is to create a system to control and monitor several of the most important features for successfully growing leafy greens and herbs from seed to harvest in an indoor hydroponics system. James says that this system will consist of four sections: water treatment, germination, seedling/microgreens, and nft channels. To ensure that the system is running as efficient as possible, James will focus on measuring energy, water, nutrient, and other material use while controlling the nutrient solution, temperature, and lighting.

 

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James got off to a good start with a rough draft of his circuit layout, and mentioned that he would like to add PH, water flow, and TDS sensing to the schematic later on, but was unsure if the cost was worth the minimal benefits these sensors added to the system. He also mentioned that he left several components off of the schematic for the time being including logic level shifters, and many of the supporting passives.

 

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Building the growing structure was first on Jame’s long list of things to do, and he quickly knocked it out using 2x4 lumber for the frame. The frame will hold a large reservoir at the bottom that will hold the hydroponic solution and three pumps. There will be three trays above the reservoir for plant growth. Each section will be 2'x4'x3.5” and will hold three inches of media. There will be two foot of height between shelves with each tray being covered in pond liner. Two trays will be filled with growing media and that will be flooded and drained at regular intervals. The third will be used for experimenting with aeroponics or some other method that will not require media.

 

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With the frame built, James added the lighting and used a mylar film to increase the reflectivity of the shelf. “I started building the trays and the lighting on one level. I have done this as inexpensively as possible mostly using materials I have lying around,” he said. “ What I have to use is several daylight spectrum and warm red CFL bulbs, Y-sockets, socket to plug adapters, and a roll of mylar. Mylar is thin, fairly inexpensive material that reflects more than 90% of light.”

 

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With the lighting sorted, James was ready to move onto lining the trays with pond liner, and getting the pumping hardware setup. 20-mil thick HDPE pond liner was selected, for the task as its thickness adds a layer of resilience to the system. Unfortunately this created some aesthetic issues for James, and he noted that it was tough to cleanly fold into the corners of the frame. When he was attaching one of the bulkheads, James accidentally tore the pond liner with his wrench. He patched the tear with more pond liner, but said there was still a small leak present.

 

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With most of the frame and hardware built, James moved onto configuring his Beaglebone Black as the systems Webserver that will run the OpenHAB web interface. He will use this interface to control and monitor the hydroponic system, and may switch to a custom-designed web interface in the future.

 

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After a couple of weeks, James realized that he was running out of time to implement everything he had planned, and decided to forgo creating a custom PCB for the project. Instead, he said that he would use breakout boards and an Arduino to interface the sensors, then relay that data to the EZR32WG via UART. While this system might not be as clean and streamlined as his original plan, James says that it will still get the system up and running in time for the end of the competition.

 

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In this schematic there are are eight relay outputs controlling three lights, three heaters, and two pumps. There are four temperature sensors, one water level sensor, three light sensors, and one current sensor. James says that this solution will provide feedback for 6 of the outputs and measurement of total power used.

 

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Just last week, James started the process of germinating his lettuce seeds using the a rockwool substrate. He says that he began the process on 10/19 by soaking 65 1.5” rockwool cubes in water with a ph of 6.0. I usually soak them for at least 12 hours. This accomplishes two things. For one, it helps lower the ph of the cubes so that they do not raise the ph of the system. It also helps to remove some of the loose particles from the cubes that would otherwise end up floating in the reservoir or stuck in the pump filters.

 

 

Update 11/25/2015

 

Since we last visited project: Vertical Hydroponics, a lot has happened in James’ life. Before we get to the big news, though let’s check out the progress that has been made on the project. When we last left off, James had just finished planting his seeds, and kickstarted the germination process. Since then, he has worked out some kinks in the Arduino-based automation system.

 

 

James started by calibrating the liquid-level measuring system, and tackled the painstaking process of filling his nutrient container one liter at a time. After each liter of water was added, a measurement from the Arduino was recorded. All of this data was then compiled into a table that could be used to create an algorithm that would calculate the volume of liquid remaining in the reservoir.

 

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Unfortunately after the liquid volume measurement post was made, the project seemed to stop, and we did not hear from James for a few weeks. As it turns out, he had the best excuse one could have for letting his project go cold. In the weeks since his last update, James became the father of a baby boy! I for one want to say congratulations to James from all of us here at Element14!

 

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James returned this week with a long-overdue update, and it appears that things are growing quite well in his vertical farm. Jame shared some amazing photos of his lettuce growing in his prototype’s system, and for the most part, they look good! While his low-pressure aeroponics seedlings did not do that well, any result from an experiment is a good result. With only a few days left in the Vertical Farming Challenge, I am excited to see what is next for James’ project.

 

If you like these post and would like to see more like them please leave me a comment, or shoot me a message. I would love to continue writing them here at Element14, and would love some feed back. How do you feel about me going back and summarizing some projects from past Design Challenges? Check out the list below for more Design Challenge Project Summaries. Note: #008 is missing because I messed up my numbering schema, and am not able to go back and change the title of the postings.

 

 

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Remember that project plan submissions is now open for the next Design Challenge here at Element14! Head over to the Open Source Music Tech Challenge page to signup today, and you could be one of the people featured here in my weekly Design Challenge Project Summaries.  Check back next week for another weekly Design Challenge Project Summary, until then remember to Hack The World and Make Awesome!