Laboratory One Research Blog

Indoor Agriculture Part 3 - Final Assembly

July 20, 2018

Indoor Agriculture Robot - front

Since the last installment in this Indoor Agriculture series, I’ve assembled the robot and began the testing phase. This phase consisted of growing, improving the software layer, and modifying the hardware design. Growing is definitely is the most difficult part. I lack a green thumb but I suspect that I can grow one 😉.

Final Assembly

With the help of a local 3D print shop, I was able to manufacture the remaining components. It took a lot of work, but I was able to assemble the rest of the robot.

Looking back, I should have printed the CAD model on paper and assembled that first. Doing so would have helped me detect the following issues: a. The back plate is too small and does not provide enough room for mounting electronic components. b. The reservior is shorter and wider than it needs to be. The footprint could be reduced by making it taller and narrower. This would also result in an ultrasonic fogger that is submerged more.

Indoor Agriculture Robot - front - off

Indoor Agriculture Robot - top

Indoor Agriculture Robot - back

“Dry” Runs

During my “dry” runs I found that the software didn’t run as desired. It script was single threaded which prevented proper toggling of the grow lights and the ultrasonic fogger. Additionally, the schedulers weren’t activating at the right times. I had to make some adjustment before the software worked as desired.

Indoor Agriculture Robot - front

Indoor Agriculture Robot - back - on

Indoor Agriculture Robot - front - on

Growing Garden Herbs

The growing process is new to me. I’ve tried to grow plants in the past and have always failed. It’s very differant than writing software… the iteration cycles are far longer!

I started with a random assortment of seeds I acquired from a garden herb kit. These were pretty old so I wasn’t too sure if they would still germinate. I read about a germination technique which utilized a plastic bag and a moist paper towel. I gave it a shot and after a week in sunlight, I started to see seedlings form.

I was pretty stoked and transplanted them all into Rockwool. Looking back, I should have let them germinate until the seedlings were more mature.

Now that I had seedlings to test my machine with, I needed to mix the nutrient solution. I did this by:

  1. Measuring out the amount of water required for the machine to function
  2. Mixing in nutrients as specified by the manufacture
  3. Calibrating the Total Dissolved Salts
  4. Calibrating the pH

This took several tries before I got a mixture which I was comfortable with. READ AS: got fed up and said YOLO.

Paper Towel Germination

Rockwool Transplanted

Indoor Agriculture Robot - on

Failure

After running the robot for 2 days, I shut it down and drained the reservior 😔. I ran into 3 problems:

  1. Most of the seedlings died. I suspect that they weren’t ready for the Rockwool
  2. The nutrient mixture was way to hot. I measured it to be 30 degrees Celsius.
  3. The nurtient mixture was full of white precipitate.

You can’t win them all. Time to try again 🌿.

Next Steps

  • Growing attempt #2.
  • Use demineralized water to address water hardness
  • Take greater care in mixing the nutrient solution
  • Updating the software to run in the background and to write to a log.
  • Updating the CAD models.

Peter Chau

Written by Peter Chau, a Canadian Software Engineer building AIs, APIs, UIs, and robots.

peter@labone.tech

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