$300 Food Computer - MVP


@wolverine1018 I actually did go ahead and put together an Amazon shopping list for this. The reason I didn’t make it more public was because I ran into the annoying problem that it won’t let me add duplicate parts to the list. The BOM requires two 12V DC power supplies, and 2 packs of the GE bulbs. This list is complete, except for the fact that you have to order duplicates of both of those parts. If you have an idea on how to fix this let me know, I keep getting an error about having the same item twice!

Goodluck with your build, please let us know how it goes and don’t hesitate to ask any questions.

Food Computer Amazon Shopping List


Hey Peter,
Ya it seems that the list can be created but you can’t add the list to the cart in one fell swoop and you also have to update the quantity once you add the items to the shopping cart.

Also, is there a difference between the si7024 and si7021 temperature sensors? I assume that the link is correct, and the title was just fat fingered bc I am not seeing an si7024 sensor by adafruit.

For the 10’ sections of PVC, it doesn’t look like Lowe’s sells those online anymore. I had to go get those in store. No biggie, just thought I’d mention it if it should be mentioned in the BOM.


@wolverine1018 I appreciate you letting me know about problems! “SI7024” was 100% a typo, I fixed the BOM accordingly. Hows your build coming so far? Please post pics/start a thread and let me know if you have any other problems/questions.

Seriously, if anyone out there reading this has some other issue they’ve noticed with our documentation PLEASE tell us. Errors with software compilation, inconsistencies, all of it. That’s why we open-sourced it, to make it better!

That’s obnoxious - I’m tempted not to give people the link even because I worry they won’t correct the quantities and get confused. Let me know if you disagree.

Well, shoot, I’m worried they’ll stop selling them in the stores as well and that was just leftover stock. We may have to go to a smaller/larger PVC (1/2" to 1") or switch materials @drewthomas89.

Does anyone have ideas for substitutes to the PVC? Keep in mind the MVP is about price and ease of assembly. We chose PVC for a few reasons:

  1. It can be cut easily (not metal), in theory with just one tool (keyhole saw - $9 on BOM).
  2. It is standardized/easy to find locally (I’m hesitant to say internationally, but I think so?)
  3. It has connectors that do not require any power tools or extra purchases.
  4. The entire frame costs less than $20.


The build hasn’t really begun yet. I am doing some of the prep work right now, but my wife and I will be moving out to Japan in the coming weeks. I figured I’d get everything purchased and partially assembled before the movers come, and I didn’t want to have it built and up and running then have to tear it down. Will update as we make progress out there!


thanks a lot for the detailed documentation. I am student working on building a food computer, and i am just a beginner. Is it possible to find out where and how to connect the relays and sensors on the food computer ? Like some document. Sorry if this is a basic question, but I was unable to locate anything so far


@Narahari Slides 13-16 “Brain Subassembly Documentation” in the first post should contain what you need. This is the main pic we have right now of the MVP wiring, I agree it’s difficult to read, it looks like there’s an extra line in there that needs to be deleted. I’ll talk to the team about fixing this.

This is the pinout:

‘3 - SDA to si7021’
‘5 - SCL to si7021’
‘29 - light relay (relay #4)’
‘31 - (reserved for relay #3)’
‘33 - (reserved for relay #2)’
‘35 - GPIO13 fan control (relay #1)’

If you aren’t familiar with a Pi Diagram, here is that as well:


@Webb.Peter Thanks a lot for the connection diagram. I will try this out tomorrow, and figure out the wiring hopefully.

Great Job Peter.

Thanks again, Regards,


@Webb.Peter I was able to connect sensors today. Thanks a lot. I used some reference from the code.

Did you try to run any tests on the sensors you connected ? Or do you have any link where there are instructions to test the sensor ?


/home/pi/MVP/setup/Validate.sh is a script to run tests on the entire system (or read the file to see the individual tests). You can run it from a command line.
Also, running individual Python applications usually have a test function. So to test the SI7021 temperature sensor, you can run the python file /home/pi/MVP/python/si7021.py.
You can run this from the Python IDE, or from the command line:
python /home/pi/MVP/python/si7021.py


I got the sotware working thanks guys! CouchDB was finally working. It took me three tries but I made it work following the slideshow you posted @Webb.Peter. I am trying to figure out how to start reading and displaying the data, i need to work a bit on that. When I click in the data entry bottom and plug in values to test it, an error appears, is that normal?


Great to hear @Juan1! What was the reason you couldn’t get your CouchDB to work? We’ve run into problems previously as well, but we can consistently replicate and diagnose.

@webbhm added the data entry button to test some features we have in development. Unfortunately, the two-way communication requires a different type of server, which we decided to not include on this last release (security isn’t finished), for now just ignore the button.

The end of the slide deck should show you how to access the CouchDB GUI as well as how to access the charting via localhost. Keep in mind, chromium (Pi browser) sometimes requires you to “clear history” in order to have the most recent data show up. This is something we hope to solve in our next release with a remote DB/UI rather than a locally hosted server.

There is also a data.txt file inside of the MVP folder that shows you the raw sensor readings if you want to go around CouchDB.


I got that, I have the openag_ui working and I can access the UI using the URL: http://{IP Address of Food Computer}:5984/app/_design/app/_rewrite.

I see this below. My question is I dont see any reading on the sensors at Water Temperature, Air CO2 or Humidity. Is this how is it supposed to be ? Is there a way to know if the sensors are monitoring the CO2 levels and other things properly for testing purposes


Woah - @Narahari it looks like you’ve got the V2 Food Computer UI running on MVP hardware?

I’m a little confused as to what you have physically built. The $300 Food Computer/MVP has only temperature/humidity capabilities in the original build. There is code written (not thoroughly tested) for water temperature, water level, and co2 as well.

If you’ve got the V2 UI running on the MVP codebase - you’re already one step ahead of us. We started to go in this direction but so far have stayed with the more simplistic UI.
Is your code on GitHub? If so please post as well as a picture of your physical build so I have a bit more context.


Thanks for the detailed information and classification. I apologize for not giving a proper information about what I am working on or what I have done.
I am actually a student working on this project, with my professor, who is building this food computer with his friend. I am working on understanding the brain and the UI part of the food computer.
So my professor, along with his friend did the connections, while I worked on installing the brain on the Raspberry Pi and understanding the Arduino
I used the below link at Github for Guidance on installing the Brain

And the one below to know about the UI

I found your post most relevant and best of all for food computer and went through this, while checking some connections. And have been searching other posts in this forum.

So i do not know if this is the MVP or the PFC to be honest. My guess is its PFC from my understanding Sorry about that :frowning:


As you asked, I have taken a couple of images, here they are,


I think you’re confused about what the different projects are. You should check out the wiki to get some context, it’s quite helpful: https://wiki.openag.media.mit.edu/

It looks like you built the V2 Food Computer. The thread you are currently on is for the Minimum Viable Product (MVP) Food Computer (nicknamed $300 Food Computer).

There are quite a few other threads on these forums that are dealing with the V2 Food Computer. I myself have built one and with the help of local volunteers (nicknamed OpenAg STL) we documented it here: V2 Food Computer Kit Build.

I encourage you to start your own thread - and be sure to tag @ferguman as I think he has a good set of code for testing the various sensors/actuators. I would also check that you are wiring everything correctly.


Hello everybody! :slight_smile:

I am planning to build what I believe will be the first MVP in Romania. I gathered a small team of tech enthusiasts and we are planning to roll out the first two models and hopefully gain as much media traction as possible. :slightly_smiling_face:

In order to maximize the reach on our Facebook/Insta page, we were planning on growing beans and lettuce but I was wondering if you have more suggestions on what would be most appropriate to help us kick start the project. :slight_smile:

If things go nice, we plan on trying to raise the necessary funds to build the first V2 Computers as well and then on to the Food Server, as we think we might be able to contribute to the cause within the EU.

Until then, thank you for the inspiration and feedback! :slight_smile:


This is great! You should connect with @Marie-Claire and @Anisa who is from Albania. They recently coordinated a meetup in Zurich. @Cezar Let me know if you have problems sourcing things. I’d be interested to know how it goes.


For those who have been having problems with the current software build, we fixed the issue with cron not working. The issue stemmed from permissions. The software guide has been updated and is available here.
The fix in the guide is now Step 23.

To fix without launching the guide, go into the command line and run the following commands:
sudo chmod a+w /home/pi/MVP/data/data.txt
sudo chmod a+w /home/pi/MVP/logs/cron.log

Libraries & Food Computers: PLIX Build (Public Library Innovation Exchange at MIT Media Lab)

I am getting a lot of help with the information you uploaded.
YouTube videos in particular have learned how to upload software to Raspberry Pi.
We are doing the same while watching YouTube.
Software updates from webcam were blocked.
“sudo leafpad /etc/couchdb/default.ini” I will not be like YouTube from here.
On YouTube, the “default.ini” window opens with lots of phrases.
However, I opened a blank window in the “default.ini” window with no text.
Please tell us how you can proceed like YouTube.
For reference, I have Raspberry Pi 3, usb cam is using USB130W01MT.
Thank you.