Slim under shelf light fixture - need suggestions

cdrake261 · Jul 9, 2012

I just recently put up a shelf over my desk and needed a slim light fixture to add some light right above my desk, I'm thinking 3 or 4 led's spaced out, small heatsink of sorts, and can be dimmed to several level of brightness. Any suggestions?

mds82 · Jul 10, 2012

i did something similar to under counter lighting. I used a aluminum bar from home depot and glue'd on some LED's. for a driver, do you have 110AC or DC power to that area. Depending what you have will determine what kind of driver to use.

cdrake261 · Jul 10, 2012

mds82 said:
i did something similar to under counter lighting. I used a aluminum bar from home depot and glue'd on some LED's. for a driver, do you have 110AC or DC power to that area. Depending what you have will determine what kind of driver to use.

What LEDs did you use? Ac is what's avaliable to this area now

AnAppleSnail · Jul 16, 2012

I suggest this build:

Go to Home Depot and get aluminum C-channel.
Get 3 neutral-white LEDs on 10mm or 20mm stars. I like Cree's 5A tint.
Get an LM-317 from Radio shack, and a switch.
Source a 12v wall wart.

Make an LM317 constant-current source. It's basically "connect Vout to Vadj with a resistor and drive the LEDs from Vadj." Find resistors to make the levels you want, and limit yourself to 3 watts per foot of C-channel.

Connect the LED in series at the bottom of the C-channel, mount that under the shelf.

Connect your driver and selector switches conveniently, and you're set.

I don't think switches commonly come over three poles...

cdrake261 · Jul 16, 2012

If I did the simple math right, that's about 1 amp to led's max?

AnAppleSnail said:
I suggest this build:

Go to Home Depot and get aluminum C-channel.
Get 3 neutral-white LEDs on 10mm or 20mm stars. I like Cree's 5A tint.
Get an LM-317 from Radio shack, and a switch.
Source a 12v wall wart.

Make an LM317 constant-current source. It's basically "connect Vout to Vadj with a resistor and drive the LEDs from Vadj." Find resistors to make the levels you want, and limit yourself to 3 watts per foot of C-channel.

Connect the LED in series at the bottom of the C-channel, mount that under the shelf.

Connect your driver and selector switches conveniently, and you're set.

I don't think switches commonly come over three poles...

cwloo · Jul 19, 2012

Try use those SMD5050 strip. It's better that more even light

blasterman · Jul 19, 2012

No, SMD strips are not better than going DIY. Some of you are just afraid of a soldering iron.

There are excellent SMD strips out there populated with Osram, Phillips, and Cree LEDs, but by and large the majority are trash made from no-name Asian factories. 'Neutral-white' in this case may by 2700K, or 8000K, and the color is usually terrible. If you can find SMD strips at a local big box store with good color and out-put, then go for it. I can't find decent ones that don't cost a fortune for 12" lengths.

If you didn't need dimming I'd advise something like a Mean Well LPC-20-350 (or equivelant) which costs a whopping $12 at Jameco. The LPC-20-350 can drive 4-14 Rebel ES's or Cree XP-Gs or XT-Es in series at 350mA and all it needs is a plug to go into your wall outlet.

For dimming, usually DC/DC drivers are cheaper and more convenient for small builds. Either use the gear AnAppleSnail advised, or if you want spend a bit more money on a LuxDrive wired buck with built on dimming. These cost around $15.00, and have pot you can turn to get full range dimming. Feed it 12volts if you want to use three LEDs listed above, or more voltage if you want to use more. Spare laptop bricks usually work very well for this.

cdrake261 · Jul 19, 2012

blasterman said:
No, SMD strips are not better than going DIY. Some of you are just afraid of a soldering iron.

There are excellent SMD strips out there populated with Osram, Phillips, and Cree LEDs, but by and large the majority are trash made from no-name Asian factories. 'Neutral-white' in this case may by 2700K, or 8000K, and the color is usually terrible. If you can find SMD strips at a local big box store with good color and out-put, then go for it. I can't find decent ones that don't cost a fortune for 12" lengths.

If you didn't need dimming I'd advise something like a Mean Well LPC-20-350 (or equivelant) which costs a whopping $12 at Jameco. The LPC-20-350 can drive 4-14 Rebel ES's or Cree XP-Gs or XT-Es in series at 350mA and all it needs is a plug to go into your wall outlet.

For dimming, usually DC/DC drivers are cheaper and more convenient for small builds. Either use the gear AnAppleSnail advised, or if you want spend a bit more money on a LuxDrive wired buck with built on dimming. These cost around $15.00, and have pot you can turn to get full range dimming. Feed it 12volts if you want to use three LEDs listed above, or more voltage if you want to use more. Spare laptop bricks usually work very well for this.

Thank you for the input...I've considered smd strip, either too much money for quality set or crappy light output. I would like even light coverage on my 6 foot long countertop I use as a desk, maybe 4 xm-l's should do it? Needs to be dimmable...if the LEDs are 36 inches off the desk, there's about a 37.5" spread of light without use of reflector and/or optics...thoughts? Also, what color to go with?

lightwater · Jul 19, 2012

I can't show you an image as it's in a rental property. 3 years ago I put an adhesive LED strip under the new kitchen cupboards, 2 metres, warm white, still a touch cool for my personal liking, but not too offensive, the supplier made a mistake & originally sent the cool white, & that really looked terrible. The warm white is bright enough, but as I can't compare side by side with with some Philips 2700 & 3000 mr16 down lights, I can't really say how cool, but probable about 3500 - 4000k roughly. But in general it gives enough light for a kitchen bench top & colour wise more or less ok!

lightwater · Jul 19, 2012

Found some photos. The 4 lights are CFLs, but with these off, there is plenty of light. (The background light is a very cool daylight on the shadow side of the building coming through the windows, so as a result the light look too warm, the image is a Canon RAW temperature 4450 & Tint +1 file)

cdrake261 · Jul 19, 2012

lightwater said:
I can't show you an image as it's in a rental property. 3 years ago I put an adhesive LED strip under the new kitchen cupboards, 2 metres, warm white, still a touch cool for my personal liking, but not too offensive, the supplier made a mistake & originally sent the cool white, & that really looked terrible. The warm white is bright enough, but as I can't compare side by side with with some Philips 2700 & 3000 mr16 down lights, I can't really say how cool, but probable about 3500 - 4000k roughly. But in general it gives enough light for a kitchen bench top & colour wise more or less ok!

What are these led strips exactly? Where do I find them?

lightwater · Jul 19, 2012

I would be battling to find the info. But it was a 5 metre roll & I bought 2 metres. The second section of lighting I had to solder on the extra wires, & then I connected the LED strip to a small transformer I got from Jaycar. The original transformer was having a "domestic" with the range hood every time I turned it on, it fried! No issues with the Jaycar run of the mill transformer. About 1 amp from memory!

I'll have a look around for some more info!....

cdrake261 · Jul 28, 2012

lightwater said:
I would be battling to find the info. But it was a 5 metre roll & I bought 2 metres. The second section of lighting I had to solder on the extra wires, & then I connected the LED strip to a small transformer I got from Jaycar. The original transformer was having a "domestic" with the range hood every time I turned it on, it fried! No issues with the Jaycar run of the mill transformer. About 1 amp from memory!

I'll have a look around for some more info!....

Any recent info?

lightwater · Jul 28, 2012

Found the details, but it was a bit thin. I bought it with all the other light fitting for a renovation from a retail outlet Ozlighting in Sydney

Description is: HV9733 Warm White Weatherproof au$74.00 for 2 metres back in 2010.

Did a bit of further research and this is most likely an old product. But found out that the product is sold in Australia by Havit whether they actually make it I don't know. (I don't know if I can post links so just add .com & .au to Havit) & the current products are on page 180 of there catalogue downloaded from "I am Building or renovating my home" button.

There are the HV7331/2/3/4 kits.

The one I got had an adhesive tape on the back so it was easy to install. I cleaned the surface first with some lighter fuel to make sure the surface was absolutely clean.

I'm sure you can get this lighting a lot easier than us.

lightwater · Jul 28, 2012

I didn't look properly! The HV9733 is on page 216 of their catalogue.

Just a reminder their transformer was cooked when I turned on the rangehood, tried to test as best as I could, there was some sort of spike from the fan starting.

If you need more light you could just run a second strip.

Slim under shelf light fixture - need suggestions

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