LED Desk Lamp Project

Sam Colwell
Feb. 2007
This page describes my efforts to create an LED desk lamp for my electronics bench. I've tried to document the process step-by-step to make it easy for someone else to follow along and build their own. One of my friends works at LED Supply, so I got a lot of the stuff from there. The materials I used (and where I got them from) are provided below.
MaterialAcquired From
05027 LED StarLED Supply
Arctic Silver Thermal AdhesiveLED Supply
345-1066-ND 1.1"x1.1"x0.35" Heat SinkDigiKey
04023B-D-350 Bucktoot LED DriverLED Supply
DC "wall-wart" 12V Power SupplyMy "misc wall-wart" box
Mechanic's Wire and Screw/WasherLocal Hardware Store
Split Loom TubingLocal NAPA Auto Parts store
Block of WoodMy "misc wood scraps" pile
Heat Shrink TubingAll Electronics

Star LED mounted to a heat sinkHere I've mounted an LED Star to a heatsink.  While the 05027 Star usually carries a Luxeon K2 LED, here I've replaced it with a Seoul P4 that I was able to get my hands on.  I put some red and green wires on the star and then glued it to the heatsink using Arctic Silver thermal adhesive (make sure you use the adhesive version of the Arctic Silver if you want to glue the LED to the heat sink. Arctic Silver also makes a thermal grease, but you would have to drill/tap the heat sink and use screws to attach the star if you wanted to use that).  It is important to have a good thermal path between the LED and the heat sink to keep the LED cool.  This is because LEDs get dimmer when they get too hot, and it can also shorten their lifetime.

Note:The wires have to be soldered on before gluing to the heat sink because it is very difficult to solder them on after gluing.  The heat sink sucks the heat away from the solder pad faster than the soldering iron can add it.

BucktootThis is an LED driver called a Bucktoot made by LEDdynamics.  The neat part about this driver is its small size.  It's only 3/4" long!  The driver runs the LED with a constant current (350mA).  Because most electronics run with a constant voltage instead of constant current, it is much easier to get a constant voltage power supply.  The driver converts the constant voltage from the power supply into the constant current that the LED needs to run properly.

Soldered LED and BucktootHere I've soldered the wires from the LED to the driver.  It's important to make sure the + and - connections are hooked up properly as the LED will not light up if you hook it up backwards.

Heatshrink on LED and BucktootBy putting heat shrink tubing on the wires before soldering them, I can just slide the heat shrink over the solder joint and then heat it (I used a lighter) to make sure the wires don't touch and short out.  I like heat shrink tubing the best, but you can use electrical tape as well.  If using heat shrink, make sure to shove it a ways away from the wire ends before soldering or else the heat from the soldering iron will shrink it before you're ready.

WallwartPrepped WallwartHere's a cheap "wall-wart" type power supply I'm using.  It's rated for 12V at 200mA or 2.4Watts.  My LED will only be using around 1W, so this supply should be fine.  I've cut the end off because I don't have the mating connector handy.  I plugged it into the wall and used my multimeter to determine which wire was + and which was -.  I put some red electrical tape on the + wire so I could easily tell them apart.

Soldered Wallwart and BucktootOnce I identified which wire from the power supply was +, I soldered the two wires to the input of the bucktoot driver.  Again, it's important to make sure the polarity is correct before applying power.  Hooking things up backwards could damage the power supply, driver, or LED.

LED, Bucktoot, and WallwartHere is the completed electrical system.  The wallwart plugs into the wall and sends power to the bucktoot driver.  The driver converts that power to way the LED likes it, and then sends it on to the LED.  The next step is to hook it up and make sure it works!

Testing the Electrical SystemYay!  It works!  These LEDs are bright!  After waiting for the spots in my vision to go away, it's time to put the whole thing together.

All ComponentsHere are all the parts for my desk lamp.  I have the power supply, driver, and LED w/ heat sink from before.  Also in the picture are a block of wood with some mechanic's wire (a stiff but repositionable steel wire) screwed to it and some split-loom style tubing.

Base Showing Screw and WireTo attach the mechanics wire to the wooden base, I just bent the wire around the screw using my needle-nosed pliers and then screwed the screw into the base.  I added a washer to help pinch the wire against the wooden base and keep it from turning.

Mounted LEDAfter drilling a couple of holes in the heatsink, I bent the mechanic's wire through the holes in such a way that it holds the heat sink.  It's a bit difficult to see in this picture, but the heatsink and LED are about 8" in the air over the base.  You can see the bucktoot driver hanging in the air from the wires.  We'll hide that in just a moment.

Finished UnitI've hidden the colored wires, the mechanic's wire and the driver inside the split-loom tubing.  My lamp is complete.

Finished Unit Plugged InAfter plugging it in, I immediately start using the lamp.  It's awesome!  It's a lot brighter than my camera makes it look, and it makes it really easy to read those tiny numbers on electronic components or to identify resistor color bands.  My camera makes it look a little blue, but its actually a very nice white and it does a much better job with the resistor color bands than the overhead fluorescent lights I have in my lab.