So, in keeping with current trends (not really but it sounds good), I've started to gather the parts for an led swap on my BC 29. I'll try to do a step by step as well for anyone that has questions. I'm following CJerome's build for my swap.

Parts list and cost (what's on the way for the moment):

$ 40 (shipped) 1 Heat sink--14"x7.26"x1.3" heat sinks usa (ebay)
$156 (shipped) 12 Cree XR-E RB leds, 2 Meanwell ELN-60-48P rapid led
$ 54 (shipped) 12 Cree XR-E Q5 (WG bin) deal extreme nearing 3 weeks on delivery just be aware that hong kong doesn't always ship fast.
$ 2.57 Alloy Steel Socket Cap Screw, Button Head, Hex Socket Drive, #4-40, 1/4" Length (Pack of 100)" amazon free shipping
$ 2.70 2 packs Nylon Flat Washer, ANSI, #4, 0.125" ID, 0.375" OD, 0.04" Thick (Pack of 25) amazon free shipping
$ 8 (shipped) Multi meter ebay

Today (2/25/2010)
$ 3 Yate Loon 92 mm fan D90SM-12 12v .19A (used)
$ 8 2-6 ft computer power cords (used)
$ 4 wall wart 12v .5A (used as well)
$ 4 heat sink grease 2 little tubes
$ 1.30 Gov'na's share (tax)

$ 18.70 parts to build 2 pwm boards (2/26/2010)
$ 2.25 solder
$ 9.34 50' 22g stranded wire (25' blue, 25' white)
$ 2.30 Gov'na (tax)


$316.18 total

$16.18 over $300 goal

fan cover ($?)

two timers to power on/off lights (unless I can set up an adruino for the same $?) ($15)

Looking like I'll end up at $330 for everything I need. Not bad, only 10% over my estimated budget.

Some quick questions:

What would a desirable CFM rating be on a fan for cooling the heat sink? Just because maybe I'll go with an 80, 92, or 100 mm fan instead of a 120.

Anyone have a more or less $ total on the PWM circuit? and a pic of the finished board front/back?

where is everyone mounting their meanwells? And the PWM bit? Stand, in hood, hanging on tank?

How much should I expect an arduino to set me back $ wise? (newb on this bit)

You don't need much airflow. It's where the airflow is that is most important. If you are cutting a hole in the top directly over the heatsink, focus on noise more than anything. If you are just using the stock fan locations, more airflow. You will get more noise from that though.

For the pwm circuit, you can get the parts much cheaper online, and you could get away with less than $10 in parts for 2, before shipping though. Radioshack will rake you over the coals, but it's more convenient. About $15 per circuit.

Arduinos vary in cost, but average about $35 for a buit unit.

So the other day I spent $35 at the local electronics store, getting all the stuff to build some pwm and wiring etc.

Then today I sat down and built a pwm. Then I hooked it up to my cheap wall wart (which says 12vdc @ 500mA output) which puts out a cool 16.77 volts no load and 2.3A no load. Go figure. However the wall wart doesn't matter much, it's the pwm I'm having issues with.

With the wall wart hooked on it gives either 0-.33v DC with the pot all the way down or 5.03~ v DC with the pot turned up--no in between, no adjustments. All or nothing. Please don't laugh at my nasty looking solder job, first circuit board I've ever soldered up.

I followed this diagram (see below), and have attached pics to show how I wired and hooked it all up. Any ideas?




I can always use it to turn the meanwells to 50%, but really was looking to get full dimming capabilities--I'm stumped though, not so great on what all the little pieces do but I can put them together.

You won't be able to acurately measure the output voltage with a multimeter. If you were to look at the output on an oscilloscope, it would be a square wave with 10v peaks. No way to measure that with a meter. If you are confident that you have wired it up 100% the way I have shown it, then you should be fine and you will get 100% dimming range.

So I finally got my heat-sink this weekend, and mocked it up tonight. I was using CJerome's layout, but found I was having issues getting the measurements to work in a way I liked (my bad math is all). So I redid the measurements and spacing to try and make it as even as possible, this is my end result (with some numbers for anyone else following along). I also plan on using a drill press to tap all 48 holes and get them mostly straight, then I have the fun task of tapping all 48 holes. . .

Heat-sink measurements:

14" L x 7.25" W (7.29 exact).

The 14" corresponds to left and right, and the 7.25" corresponds to front to back.

I measured in .75" (3/4") from both left and right sides. I then measured in .625" (5/8") from both front and back.

I then drew lines in 2.5" increments from left to right and 2" increments front to back (this gave me the most symmetrical grid I could work out).

I then measured my star boards and found that .75" spacing set the screw holes perfectly for my button head hex drive screws (4-40, 1/4" L). I then centered the .75" on each junction of the grid for the 4 inner rows, left to right.

The two outer edges left and right required different measurements: I started on the same front grid intersection, but then measured .875" (7/8") from the last screw hole mark, and made the new set. So screw holes set at .75", measure .875", screw holes at .75", measure .875" etc. This spaces them evenly and leaves space for the fan cutouts.

Since I didn't want to pull my hood apart to check the fan spacing, I simply made the same cut on both sides--from left (and right) measure in 1.5", and from the back forward measure in 1". You now have a nice little rectangle to cut out.

Also the center notch--Measure in 6.625" from either left or right along the front edge of the heat-sink, and draw a box .75" wide by .75" deep (I plan on just using a large drill bit to remove the box--a .75" drill bit if I can find one easily enough).

Here is a pic just to help make sense of my ramblings. I did one test hole just to see what I was up against--and of course I didn't have a tap driver so that made my life difficult for a while--but once finished the screws tighten down wonderfully.

The black dots are where I will be tapping out holes for the screws. I also plan on pre-cutting and tinning all the ends of the wire for the leds (the blue's are mocked up on the paper) just to have smaller bites to chew on each step.



To anyone who knows: Can I use the fiber style washers they sell for computer stuff to insulate my screws from my star boards? The nylon ones I got are too big (wasn't paying attention to OD size) and I can't find any nylon ones that are the same size as my screw heads.

Fiber washers are fine. They serve the same purpose.

So I finally finished tapping out the 48 holes, after breaking 2 taps 3 times (WD40 worked better than everything else for lubricant) and mocked up the lights. I then cut to length some of the wire and started soldering the blues together. Took me a couple hours, but I got them all done. I did put shrink wrap on anywhere it looked like the bare wire might touch a pad.

Then I wired in the dimming circuit and plugged it in, making sure it was all the way down, then plugged in the meanwell (which I soldered on just to test the lights). Slowly turned up the pot--and nothing. Nothing at all. Unplugged it all and after about 6-7 seconds all the blue led's flashed on and off.

Pulled off the dimming circuit and found an 8.7v 200mA phone charger and hooked it up. Then plugged the meanwell in, and wow those are bright.

I now need to adjust the meanwell to 8.7v so that the mA match (to give me up to 1000mA @ 10v), take all the lights off and machine out the fins for the fan, then put thermal paste on the blue's then wire up the whites and add thermal paste after a test of them as well. And then figure out what I did wrong with the dimming circuit (pain in the butt).

Here are a couple of pics, and the whites will probably get done tomorrow, or friday.

So I did finish my lights. The whites went about as well as the blues for soldering them together--about 2 hrs, and they light up perfectly as well. I ended up not using anything between the screws and the pads, no shorts (sigh of relief).

To notch out the top for the fan I ended up using a chop saw and some rough finesse--I found that I could slowly lower the chop saw down and it would cut a U shape almost perfectly from front to back, then if I flipped it over it would evenly match both front and back. Took a few minutes, is rather barbaric but after 30 min with a dremmel and metal bit, and only 2" on one fin it was a welcome advancement. I used a table saw and the chop saw to trim out the center post slot.

I did put thermal paste under each led before my final tighten down.

To mount it I went to my local hardware store and found some metal straps that were a couple inches too long--trimmed them to size and bent them over another piece of metal. Of course I bent them crooked and had to adjust for that, but each has 3 screws attaching into the hood, and the heat sink was threaded to allow attachment.

I did cut a hole in the hood for the main air in fan, but need to re-adjust my mounting bracketry to center it better, though with one 92 mm fan blowing in, and the two stock BioCube fans blowing out in stock locations the heatsink barely even gets above room temp.

I ended up getting some 7 strand outdoor sheathed sprinkler wire that I used to route fans and lights to the hood from the stand.

Things left to do:
Center whole assembly better (re-do mounting brackets) to allow fan to center, and to keep front of splash shield from touching.

Get a fan cover and some foam rubber to seal the intake area of the main fan.

Re-build the dimming switch, or maybe just work on an arduino?

Finish tidying up the cabinet down below.