Computer Heatsink LED Build

[Mr. Microscope]

Hello All,

 

I found this the other day in my lab. It had an IC mounted on it for a computer. I took it off and cleaned up the thermal adhesive with some acetone. It has a 12volt DC fan mounted to it already.

I worked up a model of it in Google Sketchup. I think I'm going to attempt a build on this as practice before I make the big light for the cube.

What do you think? Would 6 LEDs produce too much heat on this little guy? It's approximately 2.5 x 3 inches and about 2 inches thick. BTW, the yellow are NWs, there's one CB, and the rest RB. Thinking about ditching the CB and using 4 RB instead.

 

Thanks in advance!

[TheStar]

I have some of those kicking around too. I thought about trying something similar. What are you going to mount it onto?

[evilc66]

With the fan, it should be fine. I'd be more nervous if you said you weren't going to use the fan.

[blasterman]

Yeah, PC heat sinks tend to have terrible natural convection because the fins are too cramped. Heat just bottles up between the fins and they got hotter than hell. A small fan though fixes things.

[Mr. Microscope]

I have some of those kicking around too. I thought about trying something similar. What are you going to mount it onto?

I'm not sure about the housing or how I'll mount it, but it'll probably go over my picotope.

 

With the fan, it should be fine. I'd be more nervous if you said you weren't going to use the fan.

Thanks evil! I can't wait to build it.

[redfishsc]

Agreed with the above. The first time you light it up, run the fan and LEDs at full blast for several hours (checking it well) to see how hot it gets. My guess is you'll be fine.

[Mr. Microscope]

Yeah, PC heat sinks tend to have terrible natural convection because the fins are too cramped. Heat just bottles up between the fins and they got hotter than hell. A small fan though fixes things.

Great! Thanks!

[rockryno]

how much heat is tolerable for the heatsinks? Ive got a 9.5x5.5" heat sink with 12leds on it and with all lit up it gets pretty hot. I can touch it, but its pretty hot. not running a fan, but think i may need to.

[doctaq]

microscope..if i were running a fan on that baby i would put as many leds as i could fit on there..you could probably fit more if you used tri emitters, then put super tight elliptical optics on it..then put it in your closet

 

in all seriousness that will be tons of heatsinking and your leds will last forever

 

rock.. an IR gun is the only way to test for sure...oddly enough front side ambient air temp also plays a major role in lumen maintenance (shh.. its a secret)

[Hans Dorn]

The intel boxed heatsink has a better fin layout and a copper core. There's not much room on it, but it would take a 3-up board or something smilar.

 

 

You can get those for a couple of bucks.

[blasterman]

Cool. Thanks Hans.

 

Good, radial heat-sinks are rare, and their advantage is they work very well in the vertical position. Standard brick style heat-sinks have a convection problem because heat will pool up on top of the fins because there's no natural air flow flow. Radials allow heat to pass as it rises. and hance are much more efficient in the passive mode.

[ReggieF]

Thinking about ditching the CB and using 4 RB instead.

Yea, I'd go with 4 RB just because they look cool! ... But on the other hand, the CB idea might provide a fuller spectrum.

 

I love the fact that you did a google sketchup that looks exactly like your pic just to lay out 6 LEDs haha, ever hear of photoshop?

[Mr. Microscope]

microscope..if i were running a fan on that baby i would put as many leds as i could fit on there..you could probably fit more if you used tri emitters, then put super tight elliptical optics on it..then put it in your closet

 

in all seriousness that will be tons of heatsinking and your leds will last forever

 

rock.. an IR gun is the only way to test for sure...oddly enough front side ambient air temp also plays a major role in lumen maintenance (shh.. its a secret)

Awesome! Thanks! I didn't realize that it would be that efficient.

 

Yea, I'd go with 4 RB just because they look cool! ... But on the other hand, the CB idea might provide a fuller spectrum.

I love the fact that you did a google sketchup that looks exactly like your pic just to lay out 6 LEDs haha, ever hear of photoshop?

Thanks for the suggestion. I'm going to see how much I want to spend on drivers. to decide if I'm going to use the CB or not. I want all colors dimmable.

 

I'm actually quite proficient in photoshop, but i wanted to mock up my light in Sketchup so that I can design the housing and everything ahead of time and order my supplies cut to the proper size. You know, measure twice, cut once and so forth. I actually added the brackets and fan to my design this weekend. This thing is accurate to within 250 microns! I know, it's probably a little overkill, but I'm having fun with it. I am a microscopist after all. I'll post the image later.

[Mr. Microscope]

Okay, I finished the heat sink, brackets, fan, and LED design. Going to figure out the housing next. Here's a little movie:

 

[Reef Casa]

This is really a cool idea and I can't wait to see how it turns out. Keep updating!

[Mr. Microscope]

Thanks!

 

I've done a little more work on this design. I'm planning to make the housing out of acrylic. It'll be somewhat cubic with shiny white acrylic on the sides and a piece of clear acrylic on the bottom for a splash gaurd. I'm not sure how I'm going to attach the splash gaurd yet, but I'm planning to use 1 inch spacers to attach the white acrylic to the heat sink. I may have a white acrylic cover on top and then cut some holes/slats for ventilation. I'm not sure about this yet. I found a good source for acrylic. I think their prices are okay. The white might be 1/8 inch thick and the bottom is 1/4 inch thick. I found this neat stuff for the bottom instead of the standard clear acrylic. It looks like the sides are cyan.

http://www.tapplastics.com/shop/product.php?pid=520&

 

Here's another movie:

 

I wanted to add potentiometer knobs to the sides, but Sketchup 8 seems to have problems with installing plugins. Here's the model I think I'll use:

http://www.stewmac.com/shop/Knobs/Dome_kno...Details#details

I think they'll look nice with the white acrylic.

[Mr. Microscope]

Supply Update:

The holidays came and my wife got me some of the supplies for my light. I got 5 RB's (only need three or four for this build, but planning to use more later), 1 CB, and 1 NW. I still need to order one more NW for this light, but I may order a few more for the future. Also in the package, were some of the hex stickers from nanotuners to attach the LEDs to the heat sink.

Additionally, I went to my sister's house. Her and her husband are both engineers. So, they let me dig through all of their spare parts to salvage what I could for the build. I found three 5K Ohm pots to use with Buck Pucks (save's me about $15 on not having to buy the ones with the cheap plastic pots on them). I think I'll use the small ones on the NW's and CB and the larger one for the RB's. I'm not sure about the sizes of the posts. I think the small ones are either 3mm diameter x 15mm or 1/8" x 5/8", and the big one is either 6.5mm x 8mm or 1/4" x 5/16". Why isn't everything METRIC!!! If anyone has any suggestions on pot knobs. please feel free to chime in. I'm having a hard time finding knobs the right sizes.

 

Also, I got these two 12 volt power supplies. I'm planning to use one for the 3RBs and the 12 volt fan and the other for the NW's and CB LED's.

 

Here's what's left on my list of stuff to buy (that I can think of):

• 1x NW LED
  
• 3x 1000mA wired dimmable BuckPucks
  
• 3x potentiometer knobs
  
• Soldering Iron
  
• Solder
  
• Wire (21 gauge?)
  
• Wire twisty caps (whateverthey'recalled)
  
• Acrylic
  
• Some sort of container to contain the mess of wires and power supplies
  
• An additional outlet timer
  

For soldering irons, I'm considering the following:

$46 Weller WLC100 40 Watts Soldering Station for Hobbyist and DIYer

$26 Weller WPS18MP Pro Series High Performance 60-Watt Soldering Iron

[redfishsc]

If you are just soldering a few LEDs, then nearly any 40 watt soldering iron from Radio shack or similar place will do fine.

 

Here's the one I got for under $10. Works quite well for me.

 

 

http://www.radioshack.com/product/index.js...ProdsPerPage=60

[Mr. Microscope]

Thanks redfishsc. That could save some money.

[Mr. Microscope]

I just place an order with rapidled. I'm getting 2x 1000mA wired dimmable BuckPucks, 1x 500mA wired dimmable BuckPuck (all without pots), one more RB XR-E and two more NW XR-E's. I know everyone seems to be going with XP-G's and XP-E's, but this is my first build and I'm a few years behind the times anyways. I'll be using the old protocols.

 

I'd like to get a couple TVs from Nanotuners to add onto the 500mA driver along with the CB, but I figure I can add them later. Hopefully the TV's will be more redily available in the near future.

 

I've been having a heck of a time finding potentiometer knobs online that I'm positive will fit. So, I'm going to make my own out of polymer clay. I think I can craft something pretty nice.

 

All that's left to get for the basic build is a decent soldering iron, some rosin core solder, some wire, and wire connectors (from driver to PS).

[doctaq]

at the highest drive currents you may run into trouble running 3 leds on 12v, remember that buckpucks need two volts overhead. if you account 3.5 per led 3 leds would be 10.5, for peace of mind test your PS with a load and test the vf of your leds