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Building a COB style LED


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#1 kcmoxtractor

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Posted 18 September 2014 - 11:17 PM

I have spent the last couple months reading the DIY LED threads at rollitup,

and wanted to share links to topics with you all and show a pictorial of how

to make a DIY cob.

 

http://www.rollitup....er-them.801554/

 

http://www.rollitup....cxa3070.789575/

 

http://www.rollitup....ow-room.801190/

 

here are videos with lab and yield results comparing blue dream grown under

an Apache Tech 600 vs 1000w HPS (hortilux bulb, solistek ballast, raptor hood)

pretty interesting because this is the first comparison that i see as credible, and

it includes lab results :biggrin:

 

https://www.youtube.com/watch?v=YD8b_xkNc-o&list=PLh5EylePLJZnNuQNWC9NpOWXLFO-CziiN

 

[Direct Link]

 

here's a link to the thread with the comparison

http://www.rollitup....am-grow.813412/


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#2 kcmoxtractor

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Posted 18 September 2014 - 11:41 PM

I received my COB today, here are pictures of the LED.

 

Bridgelux vero 29 manufacturer part # BXRC-40E10K0-L-03 4000k spectrum.

This LED produces 127 lumens per watt when driven at nominal power, 81w.

10,287 lumens from a space less than a square inch :cool: . I will be driving at 85-90w,

this will cause a slight reduction in lumens per watt, but I couldn't find 81w drivers.

 

verofront1.jpg

 

verofront2.jpg

 

veroback.jpg

 

I purchased the LED from digikey, their customer service and shipping speed

were A+, item was shipped within 12 hours of purchase. only paid $3 for priority

shipping.

 

http://www.digikey.c...L-03&vendor=976

 

One of the cool things about the vero series is that molex makes plug and play

electrical connectors, here's a link for the Vero connectors.

 

http://www.molex.com...le=Introduction

 

Here's an image showing the connector beside a Vero array, you can see where

they mate. 

 

picoez.jpg

 

Normally I would have to solder these, but with the molex connectors I can just push

them until they click and the lights are ready to go!

 

Here is a PDF with data on the Bridgelux Vero 29. Spectral data, efficiencies at various

currents and graphs of how temperature effects performance in several aspects. Really

great data once you are somewhat familiar with the terminology.

Attached Files

  • Attached File  DS33   527.12KB   524 downloads

Edited by kcmoxtractor, 19 September 2014 - 12:09 AM.
reorganized a bit

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#3 kcmoxtractor

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Posted 19 September 2014 - 12:05 AM

Next is cooling and driver. For cooling, I chose the arctic alpine 11 plus

cpu heatsink. This heatsink is an actively cooled unit that was reputed

to do an excellent job with DIY cobs. 

 

alpine_11_plus_g04.jpg

 

the darker spot in the center of this image is a thermal pad. notice on the

back of the LED it had a metal square? that metal square lines up with the

thermal pad to help with heat dissipation.

 

alpine_11_plus_g02.jpg

 

Alpine_11_PLUS_T01.jpg

 

Alpine_11_PLUS_F03.jpg

 

For a driver, I chose the Mean Well LPF 90-48 constant current driver.

 

This driver is extremely efficient @ 91%, and is safe for use in wet conditions.

It has short circuit, over voltage, over current, and over temperature protection

as well. At 40 volts, it should supply about 2250 mA of current.

 

I am still searching for a driver for the fan locally. All the ones that I have seen

so far are below 25% efficiency, so the fan would draw something stupid like 5w,

which is an unacceptable % of the total system wattage IMO. I want the fan under

2w, preferably around 1.5w.

 

Here is a PDF of the LPF 90 series of drivers by mean well.

Attached Files


Edited by kcmoxtractor, 19 September 2014 - 12:10 AM.

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#4 kcmoxtractor

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Posted 19 September 2014 - 12:05 AM

First, attach a ground so that you don't accidentally shock the electronics and destroy them.

 

post-106305-0-94103100-1411679582.jpg
 

Then, put a small amount of thermal paste on the heat sink, in the center of

where you want the LED to go. Lightly press the LED into place and put a

washer over the top, 1 1/4 inch inner diameter.

 

post-106305-0-98383600-1411679580.jpg

 

Now use ~10 lbs of books to press the LED flat and spread the thermal paste.

I let the books sit on top for 24 hours to ensure the paste was as flat and thin

as possible. Some paste may seep through the holes around the outside of the

LED, use a tooth pick and alcohol soaked towel to remove any paste on the

top side of the LED.

 

The power supply for the Vero 29 I used is a meanwell LPF-90-48.

 

cobfin3.jpg

 

The power supply for the fan, I got this locally at radio shack.

 

post-106305-0-10649900-1411679579.jpg

 

Now use a wire stripper to remove the ends of the wire and pair 'em up then

use your preferred method of obtaining a reliable connection.

 

I used crimp connectors for the power supplies, and liquid tape to seal the

openings in the crimps. Connect the supplies for the fan and LED, and make

sure the connections are solid.

 

cobfin2.jpg

 

Here you can see the pico ez mate connectors attached to the LED.

 

cobfin.jpg

 

LET THERE BE LIGHT! (and lots of it at that)

 

cobfin4.jpg


Edited by kcmoxtractor, 29 September 2014 - 08:16 PM.

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#5 Myc

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Posted 19 September 2014 - 07:58 AM

 

 

attachicon.gifpicoez.jpg

 

Normally I would have to solder these, but with the molex connectors I can just push

them until they click and the lights are ready to go!

 

 

 

I usually try to avoid soldering those header connections if possible.

A tool which I find very useful is the Ideal #30-426 Service Tool - for D-sub and Double-D contacts.

Mouser and DigiKey are both really good online sources for parts.

 

If you're actually soldering the array during assembly, I also recommend a temperature controlled soldering station. You can get a cheapo at Radio Shack (their brand) which actually works pretty well. The only drawback when buying R.Shack's tool: Tips for the tool are limited. It's hard to find bayonets and other style tips other than the pointed one included with the purchase. They also offer a Weller for about $30 more - the Weller is the superior tool - just depends on how much you plan to use it and for what applications.

The reason I recommend this is because many electronic components are temperature sensitive. You must make sure not to exceed the maximum temperature over a certain duration or you may damage the component - shorten its service life, compromise its performance, etc.

 

Then, you may like to have a good "solder sucker" 

The best one I've found so far is the ED-DS017 Deluxe Desoldering Tool by EDSYN Inc. They're an American Made tool and work like a champ!

I've also found the use of the PanaVise to be most helpful in holding the board while working on the components. Rather than twisting ones self into awkward contortions, simply clamp the board into the vice and rotate it to the desired position - fewer neck and back-aches later.

 

DIY is freakin' cool. I like the feeling of potential - that with the knowledge of how these little parts work and interact, nothing is outside of one's reach 

 

 

Very interesting project. You caused me to look because I thought you were building a "corn cob" style fixture - where the leds are arranged like the rows of corn kernels along a corn cob - like would be used in a vertical/hanging application.

I re-read your commentary and still don't quite understand what a "COB" is.........can you help a feeb with a clue or two?

 

I followed your links - they are commentary heavy and photograph short (that's why I prefer Mycotopia over other OMCs - show me do it). I'm afraid I lack the patience to parse through 27 pages of commentary - I just never glimpsed a photo of a finished "cob". Hoping you can offer me some clues - or maybe direct links to relevant commentary? I would very much like to follow your project.


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#6 kcmoxtractor

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Posted 19 September 2014 - 09:53 AM

a cob is a lighting engine that has multiple led chips mounted to a single board.

 

individual COB (chips on board)  LED chips are very tiny, a little bigger than a writing pen's tip.

i will get a picture of the COB tonight and you can see how the chips are arranged :biggrin:


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#7 Juthro

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Posted 19 September 2014 - 12:04 PM

I've been fascinated by COB lighting for a while now, I am convinced they are the lighting of the future.

Thanks for sharing KC, I look forward to the updates.
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#8 Heirloom

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Posted 19 September 2014 - 01:50 PM

<p>have you looks @ advance led ?<br />
<br />
building one sounds light a lot of work.<br />
<br />
<br />
edit - I have several leds and found most commercial ones to be of little use.<br />
<br />
I still believe leds will meet the challenge.<br />
<br />
some of the performance of leds is how you use them. I think they have more use using the scrog style of growing. still big yields but takes a little longer. all buds are about the same size.</p>

Edited by Heirloom Spores, 19 September 2014 - 01:59 PM.

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#9 kcmoxtractor

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Posted 20 September 2014 - 03:55 PM

If you're actually soldering the array during assembly, I also recommend a temperature controlled soldering station. You can get a cheapo at Radio Shack (their brand) which actually works pretty well. The only drawback when buying R.Shack's tool: Tips for the tool are limited. It's hard to find bayonets and other style tips other than the pointed one included with the purchase. They also offer a Weller for about $30 more - the Weller is the superior tool - just depends on how much you plan to use it and for what applications.

The reason I recommend this is because many electronic components are temperature sensitive. You must make sure not to exceed the maximum temperature over a certain duration or you may damage the component - shorten its service life, compromise its performance, etc.

 

 

Unfortunately I do not feel safe trying to solder any connections. I have a genetic

condition that causes me to tremor/shake and I would lose my mind if I destroyed

a component in a tremor. I would love for you to link to more info on soldering though,

so any topiates who wanted to take that route had instruction. :hug:

 

You are 100% correct on the temperature sensitivity of the components. One of the

rollitup threads has a member who over heated a COB and destroyed the unit.

 

My plans are to use crimp connectors and heat shrink the connections. Do you forsee

any problems with the method I have proposed? I am no electrician by any means, just

a guy with an electrician friend who comes and checks my work before I turn anything

on and possibly burn my house down.
 

 

Then, you may like to have a good "solder sucker" 

The best one I've found so far is the ED-DS017 Deluxe Desoldering Tool by EDSYN Inc. They're an American Made tool and work like a champ!

I've also found the use of the PanaVise to be most helpful in holding the board while working on the components. Rather than twisting ones self into awkward contortions, simply clamp the board into the vice and rotate it to the desired position - fewer neck and back-aches later.

 

 

If one wanted to have a vise, but did not want to purchase anything expensive, a vise

can be made from a length of aluminum wire and alligator clips. Make a loop in one

end of the wire and screw it into a piece of scrap lumber from your local hardware or

big box store.

 

here's a video of a DIY cob style LED, this guy runs it off of a car battery, but you get

a pretty good mental picture of what's going on (minus the AC/DC conversion).

 

[Direct Link]

 

here are some images from mr.flux's thread at rollitup. thread addy is-

http://www.rollitup....ow-room.801190/

 

he uses vero 10s, which have a nominal drive current of 9 watts. using such small COBs

allows him to use a piece of aluminum "T" channel for a heat sink. he drives his in parallel,

for more details on how he drives in parallel you can read this post-

http://www.rollitup....4#post-10447122

 

now, on to pictures!

 

veroheatsink.JPG

 

verosetup.JPG

 

verosolder.JPG

 

verosolder2.JPG

 

in this image you can see the connector he uses, a wago 222.

verowago.JPG

 

here are some images from the DIY cree 3070 thread at rollitup, this gives you an

even better picture of what's going on. i love the long heat sink with multiple COBs,

this is exactly how I would do it if i were making a unit to cover 4' of width or more.

 

cobtop.jpg

 

cobtop2.jpg

 

cobtop3.jpg

 

cobtop4.jpg

 

have you looks @ advance led ?

building one sounds light a lot of work

 

edit - I have several leds and found most commercial ones to be of little use.

I still believe leds will meet the challenge.

some of the performance of leds is how you use them. I think they have more use using the scrog style of growing. still big yields but takes a little longer. all buds are about the same size.

 

advance is just evergrow rebranded, for a much higher price.

 

here's a link to evergrow's site, this is the brand of LED that mate0x and myself used.

http://www.evergrowlighting.com/

 

they have a lot more designs that they produce, but the website only shows a few. evergrow

makes lights for advanced, vipar, blackstar, and several other companies, but i am not allowed

to tell you who or i could lose my relationship with the manufacturer. you can only order from

evergrow directly if you are ordering 10 or more lights. LEDs have been better at scrog grows

because they lacked the ability to penetrate the canopy. COBs do not have these issues. here

is a plant grown under a cree 3070 cob with a light density of ~35 watts per square foot. strain

is DNA stacked kush, grower is supraSPL.

 

cobplant.JPG

 

here is a plant grown under nothing but cree a19 bulbs, same as what you can purchase

for your @ home depot for your E27 light sockets. grower is captainmorgan, strains are

deathstar (an ohio elite cutting) and critical kush.

 

critikush.jpg
 
critical kush.jpg

 

building a light might seem a daunting task, but it will probably only take me about an hour

once I have all the pieces together. tapping the heatsink, mounting the LED to the heatsink,

stripping wire, crimping and heat shrinking, that's about it.


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#10 kcmoxtractor

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Posted 20 September 2014 - 04:18 PM

here's another image from supraSPL, g13 labs sour jack @ 56 days

grown in 5 gallons of organic soil

 

cobplant2.JPG

 



#11 kcmoxtractor

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Posted 22 September 2014 - 01:26 PM

here is a much better video, same heat sink that I am using but he is going with a cree CXA 3070.

 

[Direct Link]


Edited by kcmoxtractor, 22 September 2014 - 01:26 PM.

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#12 kcmoxtractor

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Posted 24 September 2014 - 11:28 PM

[Direct Link]


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#13 Shadowlord

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Posted 24 September 2014 - 11:37 PM

Really cool thread K.C.
Will learn a lot. Thanks for the videos.
I remember you telling about this project and I can't wait to see how it turns out.
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#14 kcmoxtractor

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Posted 25 September 2014 - 09:20 AM

aaaaaaaand then i break off the tap bit below the surface of the heat sink. yay, hand tremors!


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#15 TurkeyRanch

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Posted 25 September 2014 - 10:52 AM

Der! Pretty cool technology, I will want to look at doing this eventually myself, for many applications. Thanks for the thread KC.
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#16 Juthro

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Posted 25 September 2014 - 10:56 AM

Sorry about the tap KC, I've been there.  Those small taps break awful easy.

 

Thanks for all the cool info, I look forward to more.

 


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#17 kcmoxtractor

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Posted 25 September 2014 - 11:06 AM

yeah it was a 4-40 tap, so very easy to break.

 

i am going to try a different method using thermal paste today.

 

here's a video of how to apply thermal paste in a LED application.

 

[Direct Link]


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#18 kcmoxtractor

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Posted 25 September 2014 - 04:47 PM

got the cob onto the heat sink today, have to wait 24 hours for it to fully cure.

 

used a washer over the top of the cob to keep pressure off of the emitting surface

while applying pressure.

 

here's an image of the packaging of the washer, inner diameter was 1 1/4"

cobwashersize.jpg

 

here's the cob with the washer over the top, you can see the small gap between

the light emitting surface and the inside of the washer.

cobwasher.jpg

 

here the cob has thermal paste applied, just waiting for a stack of books over the top

to thin the thermal paste. cob hangs over the edges of the heat sink slightly, but you can

see the thermal paste coming out around the edges just slightly if you look at it closely

from the bottom. i hope that means i have good contact between the thermal surfaces.

cobsetup.jpg

 

while working with electronics, wear an anti-static wrist band to avoid destroying any

components. static is extremely high voltage and can fry some electronics.

cobstatic.jpg

 

variable voltage power supply for the fan, i will run it @ 12v, current is 300mA.

i couldn't find any high efficiency drivers for the fan locally, so i had to get this one from

radio shack. it is about ~25% efficient, and i was looking for a 90%+ version. goes to show

you what total crap radio shack carries.

cobfansupply.jpg


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#19 torn2bits

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Posted 25 September 2014 - 10:13 PM

Very good thread, I've never seen anyone build a led aray.

Tap wise, if you can get 2-3 fluke taps always do when there small,this gives the tap more core material it won't break as easy.
Cutting fluid,even when hand taping use a drop of oil ,kerosene/naptha for aluminum.

Soldering is tuff to get the hang of, flux is the name of the game.
Paste flux sucks if you have no choice and use paste flux I melt it prior to use, this way you can paint it on the 2 connections.
Alligator clips for work -as-you go heat sink.
Alligator clip each wire/connector and solder in between the clips, the clips will work as your heat sink.
As you soldier the heat will travel through the wire to next component, with a clip being before the components the clips absorbs excess heat.

This if just an effort to help, if ya already know these things disregard them.
Best of luck man

#20 torn2bits

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Posted 26 September 2014 - 08:06 PM

In comparison to price, how do these add up compared to HPS? off shelf purchase?

I realize this has to be built, but what does a dit project amount to roughly?

The reason for asking is to see if for disable/ very sick people would this be an alternative for a medical grow?
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