DIY COB LED Calculator

bggrass said:
Couple questions:
What's the cob name.... Citizen? Are the different models 1212C4, 1812C4, 1818C4, 1825C4?

The PhotonFlux/W will that be the umol/s/W?

How do you get the number for the column under Photon Flux?

What are the prices on those cobs?
Click to expand...

1) It's quite complicated, but check out their version of a calculator (excel spreadsheet) - to be honest I'm really wanting to find the PPF / PPFD and the exact light spread off the cobs measure at each point 16' away from the centre up to 1-2'

2) Fuck knows

3) CLU058 is roughly $50usd
CLU046 is roughly $15usd however I know you have to buy 30 CLU046's to get that price
 
bggrass said:
Couple questions:
What's the cob name.... Citizen? Are the different models 1212C4, 1812C4, 1818C4, 1825C4?

The PhotonFlux/W will that be the umol/s/W?

How do you get the number for the column under Photon Flux?

What are the prices on those cobs?
Click to expand...

1. Yes, Citizen 1212C4, 1812C4 etc etc

2. Not sure, maybe @JorgeGonzales could chime in and help us out.

3. No clue.

4. 1212 - $12.55, 1812 - $22.93, 1818 - $32.08, 1825 - $42.80
 
bggrass said:
http://www.cree.com/~/media/Files/C...Modules/XLamp/Data-and-Binning/ds-CXB3590.pdf

To spit out the amperage I need to know the formulas for the curves on pages 10-11 as the relationship between amperage and lumens is non linear. This was already discussed in the thread, or more from the point of inputing any amperage instead of selecting the drop down menu. I have been periodically looking in the internet for a tool that can read pdf images and interprets the formulas. I just found this one but won't have time to look into it till the next weekend at the earliest. Feel free to explore it and let me know:

http://arohatgi.info/WebPlotDigitizer/

Also, the sheet you attached, it has a lumen value for every 0.05A. If you plot those points, there might a tool that will put together the formulas based on the points. It's worth looking into it.

The current numbers in the calculator are based on the spreadsheets that float around this forum, which have the numbers extracted at only a few (but the most popular, and what drivers meanwell makes) amperages.
Click to expand...

...yeah i like the new versions of the tool...

https://github.com/ankitrohatgi/WebPlotDigitizer/releases

....her 3.9 soft version...have a small tutorial vid too... ...


http://arohatgi.info/WebPlotDigitizer/userManual.pdf

Peace

Saludos
 
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bggrass said:
Couple questions:
What's the cob name.... Citizen? Are the different models 1212C4, 1812C4, 1818C4, 1825C4?

The PhotonFlux/W will that be the umol/s/W?

How do you get the number for the column under Photon Flux?

What are the prices on those cobs?
Click to expand...

Photon flux is PPF without the first P, full-spectrum umol/s for 380-780nm. Umol/s/W would be the next column over.

All the efficiency, flux, qer, ler stuff was calculated from digitized SPD charts, the rest of the data comes from the Citizen simulator.

No idea on prices...depends on how they are priced when they become more available. At CDI the 1212 is $12, 1812 is $18, 1818 is $25, and 1825 is $42. Those prices should come down when sellers here stock. I know a couple people put in pretty big orders.
 
JorgeGonzales said:
Photon flux is PPF without the first P, full-spectrum umol/s for 380-780nm. Umol/s/W would be the next column over.

All the efficiency, flux, qer, ler stuff was calculated from digitized SPD charts, the rest of the data comes from the Citizen simulator.

No idea on prices...depends on how they are priced when they become more available. At CDI the 1212 is $12, 1812 is $18, 1818 is $25, and 1825 is $42. Those prices should come down when sellers here stock. I know a couple people put in pretty big orders.
Click to expand...

Looks like I have everything to add those cobs to the calculator. I'm missing the numbers @1.75A. It will be nice to have them as well, since meanwell makes some good drivers at that amperage now. I'll add them sometime over the weekend.

I watched the digitizer demo video and it didn't mention anything about making the formulas but it will extract all the x y values which is half the battle. Gotta find something else that adds together the formulas together, but it might be even possible with excel...
 
bggrass said:
Looks like I have everything to add those cobs to the calculator. I'm missing the numbers @1.75A. It will be nice to have them as well, since meanwell makes some good drivers at that amperage now. I'll add them sometime over the weekend.

I watched the digitizer demo video and it didn't mention anything about making the formulas but it will extract all the x y values which is half the battle. Gotta find something else that adds together the formulas together, but it might be even possible with excel...
Click to expand...

https://www.rollitup.org/t/math-behind.868988/

I use a program called GraphClick, for OSX, 401 points between 380 and 780nm, etc. The rest is explained in that link, and @alesh has his spreadsheet uploaded for after you extract your SPD.

Actually, he has a csv uploaded too with all his digitized data, but I had to do all the Citizen stuff myself.

Not sure what numbers you need for 1750, but the simulator from Citizen certainly has that data covered. http://ce.citizen.co.jp/lighting_led/dl_data/sim/CITILED_SelectionSimulator_Ver5_P3728_0616.xlsx
 
I added the citizen cobs to the calc, but it will probably be another week till I update the dropbox.... long story. I need the voltage, lumens/w, efficiency, @1.75A for all four Citizen cobs in order to add the calculation at that amperage, if someone can pull them out.
 
So I put the link to the dropbox in my signature. I think this solve the future problem of "where's the latest link?" and I can always change that one if the old one stops working or something...
 
bggrass said:
I added the citizen cobs to the calc, but it will probably be another week till I update the dropbox.... long story. I need the voltage, lumens/w, efficiency, @1.75A for all four Citizen cobs in order to add the calculation at that amperage, if someone can pull them out.
Click to expand...

Did you have trouble running the spreadsheet/simulator? That's where all the data except efficiency calculations came from on my spreadsheet.
 
JorgeGonzales said:
Did you have trouble running the spreadsheet/simulator? That's where all the data except efficiency calculations came from on my spreadsheet.
Click to expand...

No, I just didn't have internet on my pc for sometime, so I haven't had a chance to look into it. It doesn't display well on my phone...
 
I just ran into what I needed to get the relationship between current and lumens/watt. I know we can definitely get it for the crees, not sure about the citizens (I still haven't looked at their spreadsheet calculator), and probably not yet for the veros as they don't have anything like the cree product characterization tool. So here's how it works, go to http://pct.cree.com/dt/index.html and bring up a cob that you need the formula for the amps and lm/w relationship. For example, I looked into cxb 3590 CD 36V. Then you go here, http://www.dcode.fr/lagrange-interpolating-polynomial and you go in the middle of the screen where you can list the values of x and y as pairs. I entered (1.4,172.1) (1.45,171) (1.5,169.8) (1.55,168.6) (1.6,167.4) (1.65,166.1) (1.7,164.9) (1.75,163.6) (1.8,162.3) (1.85,161) which I took from the characterization tool. You click find equation and there you have it on the right. Mine came to: f(x)=−1.26984×10^7x^9+1.85397×10^8x^8−1.20171×10^9x^7+4.53884×10^9x^6−1.10085×10^10x^5+1.77806×10^10x^4−1.91249×10^10x^3+1.32096×10^10x^2−5.31647×10^9x+9.49942×10^8 which looks kinda crazy buy it should work. I did not enter all points as I didn't have the time. The more points entered the more accurate the equation will come. For cxb 3590 there are no values below 1.4A so if we have to estimate it let's say at 0.5A, we'll just use the formula and hope that the pattern of the function stays the same at lower amps. With all that being said, I think I can definitely make a Cree COB calculator that will take as an input any amperage, instead of dealing with the preset ones. It will take a good amount of time as it will be quite tedious to input all the points for all the different cree cobs and bins that are in the calculator. If anyone feels like entering all the points and extracting the formulas please feel free.
 
Might not be a road you are interested in, but by digitizing charts from Bridgelux like Current vs Flux, Temp vs Flux, etc. you could make the equivalent of a PCT or simulator or any other front end. All the data points would be automatic, just need to be copied over.

I digitized Citizen stuff before finding the simulator, and the results were super close.
 
Question for you:

Would you like to post (or send to me in private) the JAVA source code of your tool? If not, I can of course understand.
It just itches me to add more data points for my COBs, at the amps I drive them and maybe add a section for easier input of the growing area.
(I think it's less than optimal that we have to calculate sqft or sqm, if the tool could do that just by entering the dimensions of the growing area)
 
flexy123 said:
Question for you:

Would you like to post (or send to me in private) the JAVA source code of your tool? If not, I can of course understand.
It just itches me to add more data points for my COBs, at the amps I drive them and maybe add a section for easier input of the growing area.
(I think it's less than optimal that we have to calculate sqft or sqm, if the tool could do that just by entering the dimensions of the growing area)
Click to expand...

I know you asked for metric sometime ago, but at that moment I didn't get a good idea on how to toggle between sqft and sqm. I got an idea today and I added metric to the calc. Please test it and see if it comes out right. The link in my signature for the update.

For the amperage input, refer to post #137. If you can pull out the formulas for each cree and citizen cob, I'll add them and will replace the dropdown amperage menu with an input box that will allow the user to enter any value for amperage. I did it for cxb3590CD36V3500K but I wanted to verify if the formula does actually graph the curve the same way it is in the specsheet. I ran into a problem with not being able to plug in the formula in any online graphing tool.... it seems that it was too long for any that I tried. That being said I did not try too hard because I didn't have time...
 
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