$300 Food Computer


Good idea about checking the I2C, I forgot about that!

@webbhm check out his full post here.


Got thinking, as long as you are 3D printing, you might consider adding some flanges/mounting points to the outside of the box. It would be good to have some way to attach stand-offs, or zip tie the unit to the box.


Left Side Starting:
PPM - 717 -
PH - 6.5
Right Side Changes: Added 1 gallon of water, and 12 ML General Hydroponics FloraDuo A+B equal parts until PPM was 971. Then checked PH which was at 6.5 still, so I added 1 ML PH down just because I know it’s only going to go up.
Right Side Starting:
PPM - 651 -
PH - 6.5
Right Side Changes: Added 1 gallon of water, and 18 ML General Hydroponics FloraDuo A+B equal parts until PPM was 1204. Then checked PH which was at 6.5 still, so I added 1 ML PH down just because I know it’s only going to go up.


what sensors are you using?


SI7021 I2C Temp/Humidity Sensor

Logitech Webcam USB- 5V


Getting close to harvest (about a week), this is 20 days from transplant and 27 from germination! Few notes:

  1. Some of the lettuce is significantly smaller than others, this is happening in both reservoirs and oddly enough on opposite corners of the reservoir even (WHY?!?!)
  2. One concern I always have with DWC is water temperature. I noticed on 9/8 that the plants appeared to “wilting” and the roots even looked yellowish. While this doesn’t appear to have really stunted my growth, it’s far from ideal, my current reservoir temp is around 23.1C.
  3. Instead of completely emptying my reservoirs once a week and refilling (a common practice in DWC) I am choosing to just add in more nutrient/water. This is partly just to be lazy and not waste nutrient, but also because it’s a short-term crop. If this was a plant I planned to keep for months I would not take this approach as the reservoir can get way out of balance (this is the downfall of PPM as a measurement of nutrient instead of individual ion based measurements).

Left Side Starting:
PPM - 909
PH - 6.7
Right Side Changes: It appears that about 1" (1/2 gallon?) of water has been consumed, because more nutrient than water was consumed the PH rose. I added 1/4" gallon of water and also added 1 ML PH down which lowered the PH to 6.
Right Side Starting:
PPM - 1110
PH - 5 - VERY LOW!!!
Right Side Changes: It appears that about 1.5" of water has been consumed. I added 3/4 gallons of water (I try to not add PH up/down unless I have to and just regulate with more water/nutrient at least in DWC), which brought the PH to 6.


Left Side Starting:
PPM - 808
PH - 5 - LOW
Right Side Changes: It appears that about 1.5" (1 gallon?) of water has been consumed. I added 1/2 gallon of water and PH rose to 5.5. I had to add 1 ML of PH up to bring the PH to 6.
Right Side Starting:
PPM - 1000
PH - 4.5 - LOW AGAIN!!!
Right Side Changes: It appears that about 1" of water has been consumed. I added 1/2 gallon of water which brought the PH to 5.5. I had to add 1 ML of PH up to bring the PH to 6. I want to focus on this for a moment, I genuinely do not know the answer to this and if someone out there has any expertise in DWC or knowledge of PH and how it is influenced I would love their input. Is the PH dropping quicker because I have not done a full water replacement and some nutrient has built up in excess (or even the PH down I added previously?)


Amazing results @webbhm! Remarkable!

We are having a blast with our first crop, but admittedly are learning about nutrients, ph control, etc at the same time so our results aren’t as amazing!

I have finally had time to start a Github repository for Open Agriculture Supply and uploaded the BOM and .stl files for printing the Open Agriculture Supply MVP Food Computer Power Strip. Software is not my native tongue so I will have to work a bit to have clear instructions in that regard, as I have more build info I will update the Github accordingly. It is here.

Brooklyn Update: Replicating PFCs

MVP Update:

An intern who did an unofficial internship with us over the summer built her MVP on top an aquarium and is running it as an #aquaponics system (we’ll be making a post about this soon).
@melanieshimano Will be using the MVP software to actuate lights/teach kids how to set up a webcam and grow with hydroponics similar to this class she has taught previously.
@jimbell & @ferguman are using the MVP software for a germination chamber with very similar functionality to the one Rob released.
@pspeth is developing a water dosing system for soil experiments in the MVP.
@drewthomas89 is installing a high-pressure aeroponics system shown here.
@briandmcgraw will be working on a Co2 actuation module and has built his MVP inside a cabinet. We will also be developing a chiller for his system as well (necessary when creating an airtight enclosure).
@webbhm is working on computer vision with the basic MVP webcam, as well as near infared imaging as well. Our goal is to try to eventually utilize parts of the the open source PlantCV platform developed by the Danforth Plant Science Center.
@iancollmceachern is manufacturing and selling kits for the brain.
They are working with GrowBlade to provide a lighting solution for it as well.
@TechBrainstorm has received one of those brain kits in NYC and it’s now on display next to his V2.

Let me know if I’m leaving anyone out, that being said, if you’re out there and have built the MVP or are in the process of doing so, it would be great to see pictures of your build or just hear your progress/feedback.


Hello folks, thanks so much for putting together this tutorial and $300 system! So amazing.

I’m pretty new to programming RaspberryPi though and have hit a roadblock installing CouchDB. Has any one else run into difficulties?

I was not able to install using sudo get apt-install (errors saying package obsolete or unavailable) and tried to install from source (but can’t gain access to port even after changing the IP address listed in local.ini).

Is there a particular version of Raspian or CouchDB I should install? Or I saw mention of pre-loaded SDs…where are those available from?

Thanks a bunch for your help!


What version of Raspbian are you using? Older versions of Raspbian are available here: http://downloads.raspberrypi.org/raspbian/images/. I had issues with installing Couchdb on Raspbian Stretch (http://downloads.raspberrypi.org/raspbian/images/raspbian-2017-08-17/) so I installed Raspbian Jessie (http://downloads.raspberrypi.org/raspbian/images/raspbian-2017-06-23/) instead.


@hwnesmith I’m sorry you ran into this problem. This is definitely an issue with the newer version of Raspian (Stretch) that for some reason doesn’t support CouchDB yet. As of now the only way to get a pre-loaded SD is to buy one from www.openagriculturesupply.com

I would suggest downloading this version and you should have no problems: http://downloads.raspberrypi.org/raspbian/images/raspbian-2017-06-23/

I will make an update to the post with this current bug. @webbhm can you be sure our GitHub repo points people to the right version of Raspian as well?

@rbaynes I believe this issue with the latest release of Raspian and CouchDB will also cause problems for people when loading the V2 software.


Super. Thanks @Webb.Peter. I’ll give it a shot!


dear Peter, late answers, but better late than never. Or this rule probably
doesn’t alway apply (I can imagine some situations).

What crops: those that are currently considered by ESA/MELiSSA for the
MELiSSA life support system, but it’s not restricted by that. So we do
expect - after some time - to get some innovative new ideas for crops and
cultivars. I included the list in this interview here:

update on the project: we had quite a productive community meetup/hackathon
last weekend, and solved a lot and found a number of new issues. we’re
still scheduled to open source our designs by (the end of?) this month.


@thiemehennis I appreciate the update and look forward to seeing your designs. Anything you can share in the meantime (pics, docs, links) is always appreciated.

I’m also very interested to learn more about your app and how you are incorporating the curriculum with the device. One concern we’ve had is how to make this extremely simple for teachers to setup in classrooms without doing any network configuration. Check out this discussion we’ve been having here: MVP - Product Design.

I’m also very interested in what your team is doing in terms of Computer Vision. It appears from your documentation here: bit.ly/MELiSSA_Kit that you will be recording a number of recipe variables based upon images. What CV software do you plan to utilize?

@hwnesmith Did you get the DB working? I’m interested to hear more about your build/goals for the MVP. I would like to hear how difficult you found the build as someone without much experience.


@Webb.Peter - Yes, got DB working and hopefully finishing up the brain + enclosure tonight. Once installing Raspian Jessie rather than Stretch, installation was very straightforward. The main issue I’ve had beside Raspian versioning is acquiring all of the parts. The BOM had a couple of incorrect parts (including a 4 GB SD instead of 32 GB and some incorrect links) that threw me astray a couple of times. Speaking of, where should I report those so others don’t run into the same issue?

Otherwise the instructions/videos have been super helpful. Really appreciative of y’all putting all of this together.

I admittedly don’t have too many lofty goals for the pfc, at least not yet. I read about vertical farming a few years back while frustrated as a volunteer at an organic farm by all of the inefficiences: water usage, vulnerability to weather (drought, flooding, heat, etc), pest control, etc. I’ve been curious in its emerging development ever since and found this site to get started at home.

I’m looking forward to getting more involved in the community, though, and hopefully contributing some too.


we have a picture of the (incomplete) prototype on the ESA portal:


Let us know how it goes! I’d love to see pics and hear about what you plan to grow (that’s the fun part).

What makes you think you need a 32G SD (I’m worried I said that somewhere in the documentation) I think that 4G should be plenty.

What other links were incomplete? Just post them here for now (working on a better way to manage BOMs). Please let me know so I can fix them, it’s very important to me that we support this release and as people continue to find access it they can be successful. If anyone out there is looking to help contribute to this project a great help would be putting together an Amazon shopping list so people can order in just one click.

I completely understand your frustrations with urban farming. The cool thing is that by learning how to use things like Raspberry Pi’s. A simple system designed to turn on an exhaust fan can help control the climate of a greenhouse for a very low cost.

Let me know what you’re interested in as you go forward, I’m happy to help you think of ideas. It sounds like you’ve got experience gardening which is actually less common than being tech savvy in this industry.


Thanks for doing this project and sharing it. I am very interested in the Food Computer, but the more advanced project is beyond my abilities and my budget. This project is right sized for me.

My name is Dave, and I’m an amateur (ham) radio operator, holding a General class license. I have a Master’s degree in a non-STEM field.

I intend to build this project; most of my materials should be here within a few days. I don’t have a lot of experience with coding, but your instructions seem straight forward, so I hope to have no trouble. But I do have a couple of questions.

I’m considering a larger enclosure, using a metal shelving unit (purchased at home improvement stores for about $80) and four grow tubs instead of two. It would be roughly the same height and width, but about twice as long as your design. I’m also considering two sets of lights and two exhaust fans. I think the channel relay can easily handle the additional amperage, but I’m wondering if there would be any issues with the monitoring and controlling software if I increase the size of the enclosure.

I’m also considering using a central reservoir for the nutrient solution and using the ebb and flow (flood and drain) method to keep the tubs supplied. I’m wondering how difficult it would be to program the Raspberry Pi to activate the pump to occasionally refresh the solution in the tubs. I think two or three times daily refresh would probably be adequate.

I also found a couple of problems with the BOM, but they weren’t difficult to overcome. For example, the Bus Tub is out of stock, but a suitable substitute was available.

I haven’t had a “build something” project in a while. Thank you again for providing this opportunity.


Please keep us in the loop with your build, I appreciate you taking the time to make an account and give us feedback, really makes our effort worthwhile.

One note with the code: make sure you get the right version of Raspian the first time go to the bottom of the first post, or just scroll up and you’ll see what I’m talking about (Jessie, not Stretch).

We’re actually designing a rack ourselves here in STL (we’ll document it once we have something functional). Here are some immediate thoughts: you don’t necessarily need 2 exhaust fans, you could just a larger fan (the relay doesn’t care if there is a 12V power, or 120V power going through it). If you do choose to exhaust with both, make sure you also have 2 circulation fans. Wind is an important factor all by itself. Another thing, your webcam isn’t going to be as cool in that you’ll only get pictures of a few plants (not the whole box). As for monitoring/sensing: @webbhm can attest to the variance in temperature both on racks, and even inside of just one MVP.

What lights are you looking at? We’re looking at full spectrum COB T8 LED’s. They come in easy fixtures/small amounts and are pretty well priced/high PAR.

Can I suggest you make a thread called “MVP - Food Rack” or something? I’d like to continue to help you out with your project as we’re doing very similar work ourselves (and using the MVP code). In terms of your questions about the pump, we have software designed for an aeroponic system that can be used for this. Another thing to note: make sure you get your pressure right with your plumbing on multiple tiers. Or at least plan to do it outside, I’ve flooded my bedroom so many times.