[rives]

The VolksLED –

After my experience with building up my hybrid fixture, I wanted to come up with a way for people to house their DIY LEDs without going to the amount of work (and material cost) that was required in that design. While having a bare heatsink with a bunch of components attached to it will work, I like the idea of having everything enclosed so that the wiring is protected and the fixture is more aesthetically appealing. This is my answer to a DIY fixture for the masses!

I had a spare heat sink left over from my hybrid project, and decided to use it for a foundation. The design of the California Lightworks Solar Flare caught my fancy – the top center fan placement, pressurizing the housing and allowing the exit air to escape through ports at the end of the heat sink all seemed both very effective and easy to duplicate. It struck me that an electrical “gutter”, or wiring trough, commonly used in industrial wiring could be readily adapted to form a housing that incorporated these design elements. The spare heat sink was 4” x 22”, so a 2’ long section of 4” gutter was purchased.






A sawzall was used to trim the extra 2” of length off, and also to trim down the gutter endplates for exhaust-air ports. Cutting the holes for the power switch and the fused power-cord header were probably the most tedious part of the project. You would think that since the parts are made out of plastic rather than some high-dollar material that they could give you more than .025” of flange to cover the hole, but being user friendly obviously wasn’t in the design criteria. This minimal flange, plus the odd shape of the device, made it necessary to do a lot of file work and test fitting to try and avoid a gaping fit. A MOV was placed across the power leads on the back-side of the header to help with spike suppression. The LEDs come with Zener diodes installed on the MCPCBs to further protect the devices.








The cooling fan was selected for it’s quiet performance – Noctua fans are well known by computer enthusiasts for their exceptionally low noise levels while still being able to move a reasonable amount of air. This model is a NF-B9-1600, which will move 38 cfm while generating less than 18 decibels. The fan is an 80mm unit, so a 3-1/4” hole saw worked well for creating a hole for it in the gutter.





Since the fan is intended for the computer market, it is 12vdc and required a separate 12v power supply. This worked out well because the two Meanwell drivers could use a 0-10vdc signal (optionally using resistance or Pulse Width Modulation) to control their dimming function. Using the voltage option makes it very simple to limit the maximum current that the LEDs will see, in this case using two small trim pots (potentiometers) that are mounted on a piece of Radio Shack circuit board. These pots were set up as a voltage divider, and the output from them was directed to the large dimming pots accessible on the top of the housing. The 2-watt power supply is from Digikey – the fan pulls 1.3 watts and the dimming circuits are only a couple of milliamps.

[rives]

The drivers selected were the Meanwell LPF-60D-54 units, capable of pushing 60 watts at 54 volts. For anyone interested in using these, they mean it when they say that they are limited to 54 volts. Other drivers that I have used in the past would go far beyond their nominal voltage rating as long as you kept the total wattage within spec. Unfortunately, these units top out at 54.2 volts, which caused me to change out one of the white LEDs that was originally in place for a red one. The four white LEDs required 57 volts and 900ma at 57 watts, and the drivers just wouldn’t get there.









The LEDs used were the LedEngin 10 watt units that come pre-mounted on MCPCBs. The 660nm red units were the LZ4-00R200, and the cool white units were the LZ4-00W00. These come with glass lenses installed, the red lens has a 95-degree viewing angle and the white one is 105-degree. Rather than gluing them down, #4 self-tapping Torx screws were used, along with Arctic Silver thermal compound to aid in the heat transfer. I liked this mounting method better than gluing them down, which I used previously, but it is a real bitch to drill that many holes in aluminum with a #43 drill bit (.089” diameter). The slightest hang-up while using the bit in a drill press gives you a short drill bit and a problem to deal with in the heat sink!





The heat sink was recessed into the gutter slightly when it was mounted. This keeps the LEDs below the face of the opening so that the lenses are protected by the gutter flange. It also allows the shortened cover plate to be used while transporting or storing the fixture, making incidental damage unlikely. The fixture weighs 12 pounds and draws 108-110 watts.

[rives]

Parts List - To come as soon as I can figure out how to format the damn thing!

[supermanlives]

wow that is kick ass. very professional looking .

[FunkBomb]

That thing is badass, just like the other one you built.

-Funk

[analogue]

Damn good job.


I don't have power tools but I would love a fixture kit like that.

[rives]

Thanks for the kind words, guys. Analogue, the tools needed for this aren't real extensive by design, but it is necessary to have a drill press and a metal-cutting saw of some type. It does seem like it would hold some promise as a DIY kit, doesn't it?

[Mr Apricot]

Very cool! How much do the supplies add up too? I want to order these supplies online and build one of these!

[rives]

Originally Posted by Mr Apricot

Very cool! How much do the supplies add up too? I want to order these supplies online and build one of these!

Total price was about $425. You are better off buying the gutter locally at an electrical supply house - they only run about $25-30, but the shipping could get ugly. They are also made in 6"x 6", 8"x 8", etc and available in much longer lengths. The larger gutters would probably need the depth cut down some to keep the weight down and keep the air volume to a point where fans would be effective.

[max 6699]

cool fixture Rives, are you not using your es 330 anymore?