BLOG# 11 - Edible Algae System - (Growing Spirulina in space)

Conclusions and Enhancements for future systems

This is my FINAL blog post in a series of blog post for the Design Challenge 1 Meter of Pi

version 1.1



Blog# 10 System Application Tests


This is my last blog for the Design Challenge "1 Meter of PI". It was an interesting journey for me. I gained  a tremendous amount of knowledge about the Raspberry PI softeware development platform, and I will continue experimenting with this technology after the challenge is complete. I am fairly new to MCU's (I've experimented with the PI, Azure Sphere and a Dragonboard). This was a real challenge for me. Up until this challenge, I had never designed a circuit on my own before. I have always relied on projects from others members here and on "".  I was intrigued with the capabilities of the PI 4. I needed to dig deep to learn more about GPIO interface to connect the 2 hats to one PI. With the help of another sponsored challengers blog post, I was able to figure it out. 

The  experience has been a rewarding experience for me. Thank you again Element14 for the opportunity to compete in this design challenge.

In my design, I was able to meet the challenge by using all the gear supplied in the challenger kit. However, I did not design for Zero gravity. I also cut back on the size of the ! cubic meter containment space. The result of my design, is a Phase One proof of concept prototype,  I intend to upgrade this design and implement said design with a Phase 2 rewrite.


  • In this blog I will:
    • Show Pictures and Videos of the operation of my design actually working.
    • I will list some Conclusions that were reached during this challenge..
    • And lastly, I will list some enhancements that could be added to my design in Phase 2..
      • These enhancements should make the growing of spirulina more hands free and automated.


Prototype Operation

  • Here is a pictorial of  my prototype, that I  implemented based on my design..
    • I had to cut up the original video into these pieces, because it was too large.
  • It is running the 6 Python scripts that  were used to implement my design. These scripts are described in more detail in the previous blog.
    • They are each running in a terminal window on the PI.
  • The Breadboard next to the PI, is handling the Waterproof sensor, located in the Glass container
  • The other Breadboard, is used for the Automation Hat Output channels, for the Heating Pad, Light source, and Water Pump
  • The Glass container contains the spirulina culture used to grow the algae.
    • It also contains the hose and air stone attached to the pump, for Oxidization.
    • And, the waterproof Temperature sensor.


The 6 scripts running

What's underneath the Green storage Bin?

It's the Growing house. I decided to shroud it with  black peice of fabric.

The next group of video's will show what is under the storage bim


Ok , here is what is under the storage bin.

Since I'm planning on using the Lamp as the only source of light in my basement, I wanted to cover the entire thing with something. This way, the growing environment is totally self contained.

The Monitor will be used now so I can experiment with everything, but eventually, a headless PI , ould be accessed remotely using VNC or @PuTTy  from a PC. or another PI.




  • some collusions:
  1. The Element14 community is a great place to learn. Everyone is so helpful and kind. I always get and answer to my questions.
  2. I need to experiment with the automation HAT a little more, specifically  connecting household electronics to the PI
  3. I need to learn more about resistors and there use.
  4. I need to learn more about circuit design.
  5. I need to experiment more with MCU to MCU wireless communication.
  6. Some of the many new things that I've learned during the challenge:
    1. Python
    2. UML
    3. Circuit Design
    4. GPIO
    5. The Water Sensor I used for the challenge
    6. The Environ HAT
    7. The Automation HAT Mini



  • Enhancements that could be added to my design, to make the growing of spirulina more hands free and automated.
  1. Using two  PI's and one PI zero W to communicate with each other over MQTT
  2. Use the Hats on there own PI
  3. Use the Display screens of each hat to present status values.
  4. Putting a MongoDB server on a PI with a 64 bit OS.
  5. Refactoring the Classes that are in my design.
  6. Add error code and severity logging to the Classes and scripts.


  • Design Concepts that I didn't have time to get implemented. I will implement these as Enhancements in the next release cycle.
  1. A PH sensor, for use in the growing Container.  I was unable to get one in time and cost effective for the Challenge Deadline.
  2. The In-take and Out-take Fans to control the airflow in the Growing House.
  3. The Room heater under automation control.




Blog# 10 System Application Tests