Signal Board for PFC v.2


#1

To move forward a signal board for the PFC v.2 is needed. The board should be reliable, straightforward, cheap and accessible. Any idea where I could get it?

I’m not sure that OpenAg Signal Board would be available shortly. It is thinkable to print the board using files from git repository https://github.com/OpenAgInitiative/openag_signal_board, e.g. here https://www.seeedstudio.com/fusion_pcb.html?utm_source=facebookPCB. But they want minimum quantity of 10 and I have no idea if the files for the OpenAg Signal Board are ready to work with.

Are there other boards to replace OpenAg Signal Board?


Combining farmbot and PFC electronics
#2

Hi Alex,

We are also building a PFC v2 in NYC and realized that this version requires the Signal Board instead of the grove shield + perfboard used by the PFC v1.

Printing the PCB from the files available in git is one thing, but the assembly is another challenge. Based on this picture, there are a bunch of components on this board, which we did not find in the general BOM:
https://github.com/OpenAgInitiative/openag_pfc2/blob/master/Instructions/Photos/brain_panel_relay_block_com_front.jpg

We just sent the BOM + schematics to PCBCart.com requesting a quote.

In the meantime, we are playing with the different sensors and the arduino protoshield to test our sensors.

Curious to know what other users of the community are doing to get their PFC v2 up and running?


#3

I too find myself trying to assemble a Signal Board and cannot find the BOM for the components of the PCBA. I have some PCBs on order and would like to get the components on order as well so that I can build my food computer. How do we formally request such documentation?

Thank you!


#4

Hi Ian,

I played a bit more with the Eagle files yesterday and learned that you can run a command to extract the BOM from the schematics editor

From there you’ll just need to do a bit more research to identify a manufacturer ID for each part. This is requester by all the PCB + Assembly services I tried.

I ended up placing an order with https://macrofab.com/ Their service was able to extract the BOM automatically from the eagle files, and their quote was < $100 for PCB + assembly. Their lead time is 3 to 4 weeks for this work apparently. A bit long, but worth it for this price imo.


#5

Hi francoisnyc,

the price for PCB is without connectors for pH and EC Probe (measuring sensors)? Atlas offers shields with pre-installed connectors, e.g. https://www.atlas-scientific.com/product_pages/components/tentacle-shield-mini.html
Maybe it could replace the headache?


#6

Hey Alex,

It looks exactly like what the signal board is doing for the atlas probes. That could work well with the grove shield approach used for PFC v1. Thanks for sharing!


#7

Hey francoisnyc,
OpenAg Signal Board is connected via rainbow wire with 16 Channel Relay Module. How are you going to replace it when using shield board from Atlas? How important is the rainbow wire? Just want to understand the roll of it.


#8

Hey Alex, if you go with the Atlas shield and not the signal board, you’ll need to wire all the rest yourself, using an arduino protoshield for instance.
If your question is how to figure out where each line is going on the arduino mega, I did not perform the analysis yet (we just finished testing the sensors), but I think the eagle schematics are the best way to go to figure it out.


#9

Another way to understand the signal board wiring is to look at the ROS fixtures which give pin assignment arguments for the Arduino firmware modules. Check out OpenAgInitiative/openag_brain/fixtures. In particular, have a look at personal_food_computer_v2.json.

Over in the Actuation using software_modules thread, I posted a couple pictures of breadboarding a bunch of LEDs to confirm the pin assignments that I found in the fixtures. It seemed good. Just be sure to use relatively large current limiting resistors if you do that–I think I used 5kΩ for each LED.

Pin assignment example

As an example of what I meant above by pin assignment arguments, this is a quote from personal_food_computer_v2.json:

    {
      "_id": "pump_2_nutrient_b_1",
      "arguments": [29, true],
      "environment": "environment_1",
      "type": "doser_pump",
      "inputs": {
        "cmd": {
          "variable": "nutrient_flora_duo_b"
        }
      }
    },

I’m not 100% confident about my interpretation below, so definitely verify it–maybe I’m wrong. But, I think the relevent bits and what they mean are:

Pin assignments

Don’t just take my word for it, but this is how I think the Arduino Mega 2560 pin assignments work:


Getting the software up and running
#10

@wsnook I confirm your assumption. We were able to change the data pin of the water_level_sensor_high_1 yesterday by changing the argument in the firmware_module as you described.


#11

Hi francoisnyc,

did you get your board from macrofab?


#12

Hi Alex,

I did not…

Not receiving any update I contacted them this week, and it turns out that my order had not been processed due to “erroneous gerber files”. I am in touch with their customer support and just sent them a missing .bor file, which was not on the opanag github, but is required by their platform to process the PCB.

To be fair with them, I read their user manual in greater detail this time, and they clearly mention the type of files expected. I hope we’ll be able to get the order going with the additional .bor file. Finger crossed :slight_smile:


#13

Hi all,

I’ve extracted the Signal board BOM, top and bottom PCB layout (PDF) and schematic (also PDF) for anyone interested in having a look or building an alternative.

Would this thread the best place to upload these files or would it be better to upload them to the Git OpenAgInitiative/openag_signal_board?


#14

Send us a PR and we’ll review it!


#15

I purchased a few signal boards based upon a link in this thread. Got my two boards. They look fine. Would do again. My next step is to solder on the components. The board has an area on it near the Atlas signal board footprint that takes various surface mount parts such as resistors and some IC’s (I think). Does anyone have a part list? I see from this thread that the BOM is buried in the Eagle Files but before i go down that path i was wondering if the BOM for the signal board is available via some other means.


#16

Hi spaghet,

Excuse my ignorance but I’m a bit of a novice on Github. I’ve attempted to create a pull request but didn’t get very far, any guidance would be greatly appreciated.


#17

Hello all, quick question. I have spoken with Jerry McDaniel from MicroFab and he has been very helpful in populating the signal board uploaded from the EagleCad files BOM. The automatic script will populate 45 of the 153 parts, but it still has 105 parts to populate. Has anyone had the chance to populate the parts list with part numbers and descriptions of the parts listed in the Eagle Cad drawings? If so, would you be willing to share? Looking to minimize the construction I need to do when I get the board. Thanks in advanced.


#18

Hi I am very new at creating my own custom PCB but, I tried to upload the .brd file in https://github.com/OpenAgInitiative/openag_signal_board on https://oshpark.com, and the site was able to read the file without any errors and render the shield without problems, you guys can check it out and see if the board is infact rendered correctly.


#19

Hi francoisnyc,

any update on the PCB from your order?


#20

Hey Alex, good timing :slight_smile: they sent me update today. They had questions about the BNCs but everything is looking good. They will send me the board tomorrow. I’m travelling next week, so I’ll post you pictures when I am back.