Build diary of Jussi's Food Computer

Hi guys,

This is a build diary or a log on my Food computer build project.
As a concept the Open Agricultures Food computer is awesome. I like the idea of growing my own salads and things in a nerdy food computer :smiley:

No more reasons needed. Whip open internet and start online shopping for bits and pieces.

As I am building my Food computer in Germany I of course used for many things on the list.
for raspberry Pie and Arduino parts I used a online shop . Came recommended and so far has worked fine.

At the start of all.
Parts for the hardware I got from local Hardware stores. Needed to be a bit creative as I could not find that insulate board with foil on either side, so I got normal insulation foam and a roll of kitchen aluminium foil. Add some glue and I’m sure it will work out :smiley:

As the size of the food Computer I thought it would be nice to add it to my kitchen. Girlfriend did not want something that stuck out too much so I designed it so that it will fit under a kitchen top. Plan is to add some wheels so you can just pull it out when its time to harvest or maintain the unit.

I measured some of the other kitchen tops in the flat and they seem to be 88cm from floor to the top. Added some clearance for the top that is 3cm thick, some more for the wheels 3cm and then a bit so it is not glued to the underside of the top 3cm. Food computer can be 79cm tall.

Kitchen tops are 60cm deep so add a little clearance of 6cm and the food computer can be 54cm deep.

In the plan I calculated that the top is 1m wide. so taking the side boards thickness of 2cm each and adding another 2cm per side clearance Food computer is going to be 92cm wide.

Planned food computer dimensions are 92cm x 79cm x 54cm.

First thing first. The Frame.
First compromise is that I could not find the PVC board at the local hardware store. Granted that I do not speak any German and spent 3h there looking for all parts. So I got tired and went for something easy. Instead of the PVC board I got some laminated shelve board. This thing has no moisture protection and I think I might need to change them as time goes by but I’ll start with these :smiley:

Shell is up next. Measured and cut and glued I managed to make the shell.
all went quite ok until I fitted it on the frame.

Did not calculate the bolts that stick out of the frame to my shell. After some swearing I just wound up welding the tightest corners and grinding the bolts off. I suck at welding… Now it fits… Sort of.

Now something is amiss. There is a gap between the font of the Shell and the motherboard panel (that wall that separates the grow-side from the fancy electronics.
Need to think of some options here. Number one is to make a new shell… Not wanting to do that. Maybe a 5mm gap is acceptable… Or not…

Well ran out of that aluminium tape so need to call it for today.


Thank you for posting! I like that you shared the good, the bad and the frustrating… it helps us anticipate some of our own future build problems. Keep posting!

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Thank you for sharing your findings. I am based in the Netherlands and ran across similar issues with the sheet material.
Is the laminated plate that you use made of particle board ?
What kind of isolations are you planning to use ? and this you find the pink foam for the plant tray ?
I will post some questions to the designers to ask for the criteria they used for choosing thier construction hardware.
Looking forward reading more from your experience !
Best of luck.

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Hi @Peperoni. Yes it is laminated particle board. I asked a Architect friend of mine and he suggested that when thisone rots away :slight_smile: could try this

The insulation is

Also planned to use it as the pink foam for the plant tray.

Hope that helps :slight_smile:

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Hi @silversson. Can I ask you what heater did you find for your food computer ? Still struggling to find the right one for me over here…


Hi @Peperoni.
Heater in the BOM is not available in Europe so I took the smallest I could find and looked like it could fit. So I wound up with this one:
Einhell Heizlüfter KH 500 (500 Watt, PTC-Heizelement, klein und flexibel)

Haven’t starter with the motherboard yet so no idea how it works. Looking at it I think it will work out :slight_smile:

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Had the same problem in Beglium for the heater had to find a small one, not to powerfull to prevent the relay to melt…
I aslo add an additional relay/ 20 amp to prevent the electrical arc to destroy the relay

I change a bit the design to a more “wooden cabinet”…getting a bit away from the original design.

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Damn… Didn’t even think of that. The heater might be too much for the releys… Its 500W. The relay is quite small… Wonder if it can handle it. 220V so arround 3A needed…

When you bought the relay board as specified on the BOM it should be OK… They are 10A rated.

Work continues :slight_smile:

I used the aluminium tape to cover the whole cover. Used up two rolls of tape :smile:

I used spacers to compensate for the crooked frame. The motherboard wall is now in straight angle and fits… Well not perfectly but its as good as its going to get for my first food computer.

Also did the lighting and camera fixture. Quite straight forward. Nothing too hard with it.

Did a test alignment of the camera :slight_smile: For ones I can say that I tested that before the whole thing is ready and buttoned up. At that point it might be abit tricky to go and adjust.
Word about the grow reservoir. I had it laying around and it was the perfect width of 50cm that I needed for this build. It is a tad bit long for this (80cm). I guess I’ll be making a kitchen top a bit wider to accommodate :slight_smile:
On top of that it was transparent. I understood that the reservoir needs not to pass light as it makes algae grow and roots don’t like light. So I painted the outside of it black with a paint that i had around. Did an ok job BUT all people that know of painting plastic items probably know that paint does not stick well with plastic. Now I know that too.
It does not peal off but if I pump it to the metal frame it will scratch off. So another hack to rescue. Black duct tape. Covered the whole thing from the outside with it. Not the best solution but now the reservoir looks cool :slight_smile:

Next up is glueing the corrugated plastic sheets on top of the cover using the spray on glue.
Man it proved to be harder then I thought. The glue sets in 20min and I just could not make all the edges fit nicely.
After I was “done” there is a corner ajar on almost all the corners… So how to fix it.
Trusty elastic glue thing to the rescue. went through the bottom and front edges of the cover with it. They will be ok like that BUT then there is the top and back corners that show. I think tomorrow I’ll pop by the hardware store and get some aluminium profile and hide the edges under that.

Next up is the mother board…


Thanks for posting your build. I’m excited about this project, and interested in making one of these devices myself. Cheers, and the best of luck…

At it again :slight_smile:

Today I was thinking of starting to solder the Arduino proto thingie together.
But it seems I did not:

  1. Order the correct stackable pins
  2. Did not order at all the Grove 4pin connectors. Must have missed them in the BOM

Not that there is nothing to do :slight_smile: So Started with the air exchange unit. Got my plastic box cut open for the heater output and also a hole for the air to come in. As the heater I am using is not straight from the front I used my trusty elastic glue :slight_smile:

Did the matching holes onto the laminated board. Cutting it with Jigsaw and one of those huge hole making drill bits I noticed it rips the laminate at the other side of the cut. I hate it when things do not look proper.
So I decided that the grow space side of the board should be taped with aluminium tape too :slight_smile: just to add reflection. It also hides the jagged edges of the cuts.

Also added wheels under the frame so it slides nicely under the kitchen top that is designated to be its home.

Starting to put things on to the motherboard.

I’m still quite clueless on the Arduino and Raspberry pie and how they work but I’ll just keep putting things together and fixing problems. Should be fine :smiley:

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Wow! Looks great Jussi!


This weekends work has amounted the cover having a window and aluminium profile on the edges. Looks nicer this way I think :slight_smile: Window is tricky as the magnets are so strong that they sometimes rip themselves off the cover. I added spacers under to make for a bit more surface to be glued on the cover but still… that is one tightly closed window.

Started to connect things on the motherboard. Finished up the heater. Connected the extension cord onto the board. Drilled a hole for the sensors and air hose to go through. This browed to be a mistake at the end as the electric socket boxes needed that space.
Started to work on the electricity socket box. The EU version of this is quite a bit different and takes quite a bit more space then the US version. Did the relay into a separate box and wired everything up. Hope all went well and I will not burn down my house :smiley:

See that hole I planned to run the sensors and everything going into the reservoir through. Is nicely under the boxes.
Need to fill it and make a new one.

Had some leftover sleeve and ran the grove cables from the relay box with a green sleeve on them. Looks nicer :slight_smile: and cleaner. Also wired up the 12V supply but forgot to take a photo of that. Well next time.

Now I am at a point that I need to wait for groove connectors and some other items to arrive before I can go forward. Hope they come soon and I can start growing things in :slight_smile:

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Hello Martin,
I am building also in Belgium. What kind of CO² sensor did you use?

The one on the BOM, I had to import it.

Same here. I think the sensors are the one part we could try to find a solution that does not cost as much as now and would be more generaly available.

@silversson i notice that you have a fan both on the inside of the grow chamber (circulation fan?) and one on the controller side. What is the latter for ?

It is to vent air into the grow chamber. There is (will be) a hole at the back of the cover to let air out. I guess it is used to cool the grow chamber and control the CO2 level.

Ok holidays are now done and back to work on the Food computer.
Next thing is to get that Arduino Mega + Proto shield + Grow shield soldered ready and connect it to Raspberry pie.
Sounds easy? Well as it is my first ever use of Raspberry pie and Arduino I must note that this is where our nice Forum comes super handy. The motherboard assembly guide kind of breezes through this part :smiley:

Gathered all the parts and started soldering the stackable headers on the proto shield. Almost all went well except two things. The sets of stackable headers I bought were not the right ones.
Here is a picture of a complete header set for Arduino mega proto shield.

My set was missing the 10pin header at the top left on the picture, 36pin header at the right side of the picture and 6pin ICSP header that goes into the center of the board. Ordered new ones and got everything except that massive 36pin one. Luckily I had some pin rails.

Used them to replace the 36pin connector.

Irritation of starting work, noticing missing parts, ordering missing ones, again start work and round and round it goes. Days delays… :smiley:
Finally I got the parts.

Being the master solderererer I soldered the bloody 6pin ICSP header wrong way around. When all the other headers have their legs one way the ICSP header should go the other way. Legs sticking out where other headers have the black plastic part. Not an easy fix. But after a hour of removing solder and re-soldering I was finally done AND then I find out that the header is not even used…

Next up is connecting the grow connectors. Did a even split to fit all the 9 connectors nicely. Its pins do not directly fit and you need to spread them out to solder them in. Also good to note is to use more then normal solder here as you will be connecting wires to them.
Thanks @adrianlu for the wiring schematic. It was super helpful. I started with the 12V connectors both plus and minus.

Next up I connected the rest of the wires. Used a black for ground, blue for voltage and yellow for signal wires.

Time to stack them together.

Used instructions from @JoshSinykin to upload the Arduino SW and flashing the Raspberry pie memory-card. Thanks @JoshSinykin :smiley:
Surprising was the hours long the flashing the card takes. Maybe my reader is just slow as a snail. Left it in the workshop hoping it will be ready by tomorrow.

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