I made the task lights from C6 mini LED Christmas lights, bought on "after holiday" special.
I will be using acrylic strips cut from scraps left over from another job to mount the LEDs.
In case anyone is wondering, I am renovating the kitchen as money allows. And since this is a working kitchen, there is bound to be a few things sitting on the counter. Yes, those are custom built cabinets, that I made. To see more of them, check out our website.
Total cost for this project comes in at around $3 per unit, not including the build time. The most expensive part of the system is the $15 universal adapter bought from wallyworld.
Anyway, on with the show.
My first instructable, so have fun with the rating wars for good or bad!
I'll try to answer any questions anyone might have about this or the cabinets. When the weather warms a bit, I will try to put together another instructable showing how I build the cabinetry.
Step 1: Harvesting the LEDs
On these, the teardrop jewel is just pressed into the lamp base, easy to pull apart.
The leads are then bent straight, and the LED removed from the base.
Step 2: Preparing the Acrylic
I cut the acrylic with my skilsaw, but there are many methods available for this, use your favorite search engine to find a method you like.
My strips are approximately 1-1/4 inch wide, you can use whatever width is suitable for your application.
I bent my strips to give a bit of room for the leads from the components. A word of warning here, acrylic gets somewhat more brittle after heating and forming, so make a few extras. You might break one or two while performing the next step.
I won't go into how I heated the acrylic strips, the method I used was inherently dangerous. I would suggest using stand-offs made from short lengths of plastic tubing.
Step 3: Drilling the Acrylic
Drill your holes in whatever pattern you need for the area you will be lighting.
I didn't worry about accuracy on hole placement, close enough is good enough.
Next, I drilled holes for the resistor leads.
A good source for small drill bits is a torch cleaning drill set, procured through a welding supply house, or auto parts store like NAPA. I don't think places like Pep boys, O'reilly's, Auto Zone, etc would have this.
Step 4: Stuffing the Components
I am powering my lights with a 12V source, so I used an online calculator to figure the correct resistor value for the LEDs. Yes, I could have figured it out using Ohms Law, I was being lazy.
My LEDs have a Vf of 3.5V for the white and most of the colored, and Vf of 2.6 for the remainder of the colors. I cheated a bit, and reduced the required current in the calculators to compensate for the different Vf. Works fine.
I didn't have the proper value resistors on hand, so I figured up a series-parallel set for the required resistance.
I places all the white LEDs next, making sure of the anode/cathode positioning. Next, I added the colored LEDs. Without the colors, the light output was too white.
Next I bent the leads together, and soldered. Be careful with this step, you can easily overheat the LEDs.
Step 5: Wiring It All Together
I used 24awg bell wire I had on hand to wire up the sets. Red for positive, White for negative.
Yes, I hooked it all up as a parallel circuit. Before anyone shoots me for it, in this case it works well with the power I'm supplying to the setup.
Step 6: All Done, Checking It Out.
I am using a universal adapter from wallyworld to power the task lighting, set for 12V 1300mA max. Total draw as currently installed is 460 mA. As I get more upper cabinets built and installed, I will be extending the low voltage wiring and adding a second low voltage circuit when the first one nears 900mA draw. I have been running the setup as currently installed for almost a month, with no failures yet.
I have installed a mains switch controlling a single outlet in the basement under the kitchen. The adapter plugs into this, with the low voltage wiring brought up through the wall to the underside of the cabinets.
For all you purists out there, I know I risk having to replace burnt LEDs wiring it up as I have. It works. No LED sees more than 16mA. With all of this, the light level on the countertop is very good.