Custom LED Light Panel FCV2.0


#1

First and foremost greeting, as I am new to the forum please excuse me if this topic has already been covered I am slowly working my way through the material on the forum.

I am looking to design a LED panel which will fit in the FCV2.0. Before I started the design I was wondering if I could get a little information about what the light requirements are. From reviewing the BOM and the incumbent LEDs (GE tetra power) are 12VDC (I will have to do some more research but I am assuming the constant current driver is included in their package) and your main power supply is a 24VDC; again I would assume the LEDS must be in series parallel configuration.

Here are my questions in no particular order:
What is the power budget for the LEDs?
Are the red, blue, and white channels individually controlled, and if so how (PWM or constant current dimming)?
What is the target PPFD? (Assume around 2.0umol/J)
Is there a particular red to blue ratio you are look to attain?
Are you open to adding additional spectrums out of the PAR range UV or ~720nm red.
How much do the GE LEDs cost?

Once armed with this data I will mock up a quick design, if done right it should reduce the BOM cost for the LEDs, and make it a heck of alot easier to install.

Thanks


MVP - Product Design
Greetings Community - Lighting PCB
MVP - Product Design
Greetings Community - Lighting PCB
#2

Poitrest,

Did you receive a response ? How is progress ?

CGaines


#3

@Poitrast, Caleb just gave some details and links about the LEDs in his new post over at V2 Food Computer Kit Build


#4

Check out the light panel instructions for more information about the lighting.

Here it shows the ratio’s of colors:

Follow this post and I will be posting lots of pictures of the lighting sub-assembly within a week, but there are already lots here.

Let me know if that doesn’t answer questions and I’ll try to help, I would be very interested to hear your ideas on alternative lighting, I have been involved with that conversation on this thread as well.


Discussion on the aptness of the light sources used in PFC
#5

Good afternoon sorry for the late reply, I’ve spent the better half of last week at a lighting conference. I have taken a look at the GE lights Caleb spoke of in his post and I’m certain I can put together an LED panel of comparable specs. Later this week I will post my solution for feedback. As far as manufacturing is concerned I will seen what I can work out with some of my contacts. At the very least this should give a solution until GE rolls out their light in full production. Depending on the final cost of the unit I may design two, one with midpower Leds and a second premium panel with Cree’s latest offering.

Best Regards,

Dan


#6

@Webb.Peter, First off great job on the build the pictures looked great.

I have a couple questions I hope you can answer for me, or at least confirm my evaluation of the system. My current understanding of the light panel is as follows:

24: Red Modules, 1.5W/unit, 12V supply voltage, total ~36W
8: Blue Modules, 1.8W/unit, 12V supply voltage, total ~14.4W
10: White Modules, 1.32W/unit, 12V supply voltage, total ~13.2W

Total Light Module Wattage ~63.6W

For the life of me I couldn’t find a wiring schematic for the lighting modules. Are the modules wired in parallel supplying 12V per node, or is there a 24V rail requiring a series parallel configuration of the lighting modules? I only ask this to steer my design considerations for the module, if a 24V or 36V rail is available a linear constant current source would be acceptable with minimal loses, but if only a 12V rail is present a linear constant current source (like a resistor in GE’s case) doesn’t make sense as we would take ~25% converter loss before even creating one photon. The higher the input voltage the lower the converter loss in a linear system.

Solution

4 Independent lighting panels with 36 LEDs on each panel.

4 panels would take the place of 42 modules cutting the wiring the down from 82 wires to 12.

Optics
I have spoken with my contact over at Khatod and he recommended the following optic: http://www.khatod.com/Khatod/PublicTempStorage/knac36xxads_technical_detail3162871228305.pdf

This can be outfitted with a silicone gasket to give the appropriate IP rating. Cost-wise they should be around $10 a piece.

LEDs
Mid-Power LEDs either the 757s from Nichia or a horticulture line of LEDs from Lumileds. The advantage of the Mid-power LEDs is two-fold cost and efficiency.

Cost
I am still working on costing for the unit but my goal is to get the price below $25 a piece (don’t quote me on the price yet).

Please any feedback/questions anyone has are more then welcome. It is always nice to get an alternative viewpoint whenever designing.

~Dan


#7

@Poitrast Did you see my most recent post that had pictures of the lighting, I hope that was beneficial. In my last post I provided a link to the layout of colors for the lights, you are correct though that there isn’t really a wiring guide.

They are powered at 12V, the 24V power supply is only used for the chiller. I wish I could answer you in more detail but I actually still have not powered them on yet, I hope to get to that tonight or tomorrow.

If you’re willing to share any pictures/prototype designs please do. I’d be very curious to see the direction you are going in. Depending on the availability of parts and the price I would be interested in building this light and perhaps using it for the MVP.


#8

@Webb.Peter I did see your most recent post of pictures, and it was indeed helpful. Of course I will be more then willing to share any designs I have. Tomorrow I will push the proposed solidworks designs up to github, and I will write a brief summary of the spectral output and power requirements for the boards. Today will be a wash as I’m heading over to the Media Lab this afternoon.

How much extra headroom is there in the 24VDC power supply for the chiller? Could we steal 60W from it?


#9

@Webb.Peter I still need to add the finishing touches to the light modules (will probably get the time this weekend). Attached is a preliminary picture of the layout and design concept. The picture should at least give you an idea of where I think the design should go. Small details like the mounting holes will be added this weekend. Let me know your thoughts.


#10

Looks like a good start. I’ll get back to you about the 24VDC by tomorrow (not around PFC right now, have you checked the BOM?).

This link is returning a 404 error.


#11

@Webb.Peter, Let me take a look at the BOM. Try this link for the optics. Different beam angles are offered for these; once I get some samples in house I will determine the final placement and correct beam angle.


#12

Figured an update is in order. Prototype PCBs for the light engine have been ordered (OSHpark), and sample optics are on the way from Khatod. Once the PCBs have landed I will reflow some LEDs and get to testing/qualifying these modules! More information to follow.


#13

I am also trying to build a Custom LED Panel, but can’t seem to find any details on how the default LED solution is powered. It would be very nice to have some kind of schematic showing how the LED’s are connected (serial or parallel) - have any of you run across this?


OpenAg™ Personal Food Computer v2.0 (beta) [Documentation Release]
#14

Hey guys
Are there any updates on the custom light panel for the PFC V.2.1?
Could you share a link, where we can get/buy the lights from?


#15

For 3W LED you need constant current power supply like these I haven’t experience with these one.
These supply can drive from 8 to 21 white or blue LED (each have arround 3.2V) and 50% more red LEDs (2.2V). Led must be connected in serial.
I have these ones and work fine with 6 blue/white and 3 red in serial for now (3 days:slightly_smiling_face: )

For 1W LED current must be arround 300mA, voltage is the same.