Greetings Community - Lighting PCB


#1

Hello community, my name is Dan Poitrast and I’m one of the newest full-time members of the MIT Media Lab Open Agriculture Initiative. My official title is Mechatronic/Embedded Systems Engineer. What the title means is, I will be working intimately with the hardware and software integration for the PFC. One of the first tasks I will be tackling is a review of the current hardware used in the PFC and the creation of PCBs for easier manufacturing and hopefully reduced cost. As with the rest of the PFC these PCBs will be Opensource and we will find a path for the community to get their hands on these boards. I would love to hear the communities feedback on any of the current hardware used (especially sensors). Once the OpenAG team has decided on any changes to the hardware we will let you know as soon as possible, and as always value any recommendations you may have.

I look forward working with all of you, and please feel free to ask any questions you might have!

Dan


#2

what kinds of PCBs are you thinking of?


#3

Great to hear you’re a part of the team @Poitrast!

I’m curious what you’re looking for when you say “a review of the current hardware” I think it is very difficult to determine what is “good” and what is “bad” without clear cut goals. Is price more important than ease of assembly? What’s more important: modular/hackable design, or a more robust and reliable solution that can be operated by someone without a strong technical background.

Will your PCBs be intended for just the PFC? Is the plan to use the same on the Brain Box & Food Server as well, or not?

Lastly, any other insight you could provide about the outstanding hardware questions the community has had regarding chiller and lighting and OpenAg’s plan going forward would really be appreciated.


#4

Good Afternoon Peter,

Let me begin with my definition of good hardware (as I do agree it is rather difficult to define as there are a plethora of factors). The aspects the team will be evaluating are: supply chain (ie availability from reputable sources at large quantities), communication protocols (Ideally everything would speak the same language whether it is I2C ect. The protocol also lead to hackability for the community, and ease of use for the non-technical folks.), reliability (this can be construed both as the longevity of the sensor, and the physical package), and of course price.

As I have a lighting background I will be pursuing an off the shelf solution or custom light panel which will be available to the community. With the chiller I am not actively seeking a solution at the moment, but it will be something I will try to address in the future.

The intent for the PCB is to create a solution which will ease the manufacturing aspects of the various food computers. It will consist of: lighting controls, relays, the sensor back-end circuitry (as far as the circuitry to drive the sensors), power conditions for the various sensors and circuitry, expandable spots for new sensor, replaceable fuses, and various circuitry for testing the board and the system. The PCB will be opensource and created in Eagle for anyone out there who wishes to add anything additional. In addition, the PCB will have wire connectors for ease of integration. As with the light panel we will get a CM on board to help manufacture/distribute the boards for the community. Overall the PCB will make the PFCs easier to make, more reliable, and less expensive.

Thanks,

Dan


#5

Great criteria, glad to see that the thought has been put into developing those.

Any idea on a timeline? I had been following your lighting thread with interest. Also, you should talk to @LubanaEkdeep .

If you come across anything or hear talk of it please post about it and tag me. I’m really hoping someone figures out a much cheaper solution. The other addition is that the current system doesn’t chill the reservoir water temperature. To me, this is equally as important as the air temperature if not even more. I currently still am employed at a refrigeration manufacturer and have access to a lot of brains I can pick when it comes to thermodynamics. That being said, I have a very weak understanding of it myself but want to learn more. I feel as though someone with enough experience could hack an alternative out of a mini-fridge or something.

Here is a good discussion of PH/EC sensors.

Here is a good one on Co2 sensing.

For Temp/Humidity on MVP we used SI7021 - $8.99 I2C pretty common simple Python stack.

BTW, on the [Software Roadmap] the link to the hardware roadmap is giving me a permission denied :frowning:

Lastly, what board are you developing this for? I was following this thread discussing controller alternatives and curious how that will impact your work.


#6

@TechBrainstorm @adrianlu @nav @webbhm @juhnke @yusuf.khan.su @ferguman

Any thoughts or improvement ideas for current hardware/sensors?


#7

I’m using sense resistors with an amplifier on my LED control board.
Everything else is a digital output in my system so I’m estimating power usage by running time.

Current transformers would work well for measuring system power. They’re placed on the AC input


#8

Thanks for tagging me, @Webb.Peter

I have actually been doing some literature review about the LEDs’ spectral composition, and wondering whether the sources deployed are adequate for the same or not. My apprehension is that the LEDs are having a constant source of current during the growth cycle, however, in an artificial and controlled environment, we have far more control. I have been wondering if monitoring the growth stage, and using a composition of energy which ensures for maximum growth - during that stage - will significantly improve the PFC - both, in quantity of output and its quality.

However, I am just betting on this intuition. I shall be conducting a lot of literature review for the upcoming week, and see if a palpable growth stage based light composition exists or not, for any species of vegetation.

Further in, the deployment of this system will be very simple. All that is needed is a camera, a feedback to the micro-controller based upon the processed images, and, hence, the micro-controller changing the currents across the LEDs, leading to change in energy compositions.

I’ll be glad to know both, your and @Poitrast 's, thoughts on this nascent idea. I’ll work out more, upon this, till then.


#9

@Webb.Peter I think you have covered most of the feedback i had on mind. @Poitrast has mentioned about reducing the cost and make PCBs more available for users, which had been the biggest pain point for me personally. I will give more inputs if and when it cross my mind.


#10

Not that I have publicly seen. You might look into people who try and manipulate the color or flavor of lettuce using red/blue light. I know Phillips has done loads of research on LED lighting. Perhaps @Poitrast can help you out more.


#11

Thanks @webb.peter From our build, some insights that would be beneficial to the device (IMO) are:

  • Need a solution to figure out how to reduce wiring obstacles. That took forever…
  • LCD Screen with direct links to each control (a nice GUI would be awesome too, but baby steps…)
  • Lights that can have some spectral adjustment capacity…and are available on the market
  • Better light insulation (from the outside in, and inside out)

Thats all i have for now, but we are doing a major upgrade on the device this month with a new engineer and I am sure we will discover some new opportunities and ideas through this process

Dan


#12

Thanks @Webb.Peter

@Poitrast we are starting to build the PFC v2.0 right now. Our goal is to have the unit fully up and running in November. From what I understand, the lights are not available so I am wondering what we should do about this. Any updates?

Cheers,
Adrian


#13

@adrianlu, we should have some light available very soon (less then a month). As soon as they are for sale I will forward a link.

Dan


#14

I’m seeing V2’s more and more on the forums, and I’m curious what lights you’re using (if any).

@Poitrast Any update on the lights? Even if OpenAg doesn’t have a manufacturer or custom V2 panel yet, is there at least a recommended standard those with V2’s currently can use so we’re using the same thing? Even if it’s not ideal or capable of spectrum manipulation your
recommendations on a solid LED fixture for >$300 would be appreciated.

I’m even interested/willing to do a DIY LED - I reviewed your previous thread (before working for ML) and may end up picking up where you left off building a Custom LED Light Panel FCV2.0.

Lastly, I saw the other day this new repo on the OpenAg Git, figured I would share here as it’s relevant: https://github.com/OpenAgInitiative/openag_light_controller


#15

@webb.peter Sorry I haven’t been on the forums lately; we’ve had our heads down designing. Next week we will have ~20: 6 channel light panels in house designed specifically for the PFC and Food Server. We will test these panels, and then will have a path to market for the community to get their hands on them. The light controller link you added will be used to control the aforementioned panel via I2C.

Later this coming week I will share the new design for the Brainbox. The PCB should be a big step forward and greatly ease both the construction and cost of the food computers.


Growing Veggies packed w/ Flavor & Nutrition
#16

Dan, no worries about the delay, I appreciate you taking the time to provide an update. I’ve been watching the light controller on GitHub with excitement, I’m very interested to see what you’re using all 6 channels for (UV/FR/NFR).

I think it would be great to open up the discussion on these forums about lighting as it affects plants, both in terms of intensity, quality, and duration. So far the only open sourced dataset regarding flavor appears to be a lighting experiment (there was also an article on this) done with basil. There’s been a good discussion going on with regards to flavor and nutrition in CEA on this thread, I’m very curious the role that lighting plays: Growing Veggies packed w/ Flavor & Nutrition

I CAN’T WAIT to see the new Brainbox. I’d love to see some pics of the lighting assemblies too when you get them in, exciting times!


#17

Hey, Dan, I’ve been seeing the new lights on OpenAg’s Twitter - looks great.

Do you have a timeline on when you plan to release the new design for Brainbox and any documentation on the lights (Food Server or V2)? I know it’s hard to open-source and document this stuff - please let us know if we (the community) can be of assistance with that process. I think that V2 Lights are probably the #1 roadblock right now for everyone. Without any level of standardization in lighting and no sensors related to radiation in the V2 I think it’s going to be very difficult to compare datasets down the line and get anything of value.


Complete design of the personal food computer (and possible alternatives of some components)
#18

@Poitrast, cool!

I’m interested in PCB lighting panels.

Do you have the ability to create some sort of RGBW led PCB where one can control the lighting ratios? That is what i am most interested in. I’ve mentioned it a few times in the other threads. I need it for potentially tricking day-length sensitive crops into flowering and fruiting earlier than they usually do for cross-breeding purposes.

Thanks,
-Andrew


#19

Figured this would be as good of a place as any to post this: