Step 1: Gather Your Materials
For this project you will need:
An appropriate length of 5050 LED strips with 60 LEDs per meter (there are some that are only 30 LEDs per meter, get 60 per meter) - I got this for ~$6.50 a meter of eBay
A 12V DC adapter - I got a 6A one of Amazon for ~$10
Junction box - ~$3 @ Lowe's
An appropriate length of red/black wire - ~$5 a piece for 25 feet of 16 gauge wire at Lowe's
Heat shrink tubing (optional) - ~$8 total from electronics store
Heat gun to shrink tubing - I used my wife's hair dryer
Soldering Iron/Solder - Already had
Hot glue/ hot glue gun - Already had
Nail down clips - Already had
The total project cost for doing a 2 meter section of cabinets came out to just under $50 for me.
Step 2: Measuring and Choosing a Power Supply
Once you've figured out how many meters of strips you need, you can choose your power supply. These 60 LEDs per meter 5050 LED strips use <6 amps per 5 meters (and have a viewing angle of 120 degrees if you're interested) them means you need 1.2 amps per meter of LED strips used. Since I was going a little under 2 meters, I could have gotten by with a 2A power supply. I chose a 6A one, however, for two reasons. First they were roughly the same price and it's not like it will use any more electricity to be able to provide 4 more additional Amps. Secondly, this was a bit of test run for me. If things went well (which they most certainly did) then I was considering expanding this out, so I can power another 3 meters of light off this one power supply at no additional cost.
But that's just me. The only important thing is that you purchase at *minimum* a 12v DC power supply rated at 1.2A * (the number of meters you are lighting).
Step 3: Tapping the AC and DC Power
I didn't get a very good picture of it, but on the DC side of the adapter, I cut off the coax connector it came with and wired the positive cable to my red wire and the negative cable to my black wire.
Step 4: Distributing the Power
From the DC adapter, I took my single pair of red/black wires down to my under cabinet area. I got lucky here and had an empty space where my cabinets meet in a corner so I didn't have to drill through them. Once I got them down there, I spliced one pair of red/black wires per strip. I did three different areas so that is three pairs of red black wires.
For this part, rather than put in another junction box, or just have some electrical taped up twist caps, I went ahead and soldered them together than shrunk white, heat shrink tubing around them.
I proceeded to shrink white, heat shrink tubing (to match my cabinets) down the entire length of the wires. It probably wasn't necessary in the long run since you can't really see them, but on those few occasion where you would, it makes it look *very* nice. I don't own a heat gun, so I ended up using my wife's hair dryer and a towel. You place the tube between the towel and the hair dryer and it quickly gets hot enough to shrink. Be careful to let the hair dryer rest often so you don't damage it or trip it's temperature sensor forcing it to shut down for a while. Once all your wire is in place you're ready to move on!
Step 5: Wire and Stick the Strips
1) Make use of the preinstalled wires. The strips I bought already had a red/black wire soldered on correctly. There's no point in re-inventing the wheel, use what they provided!
2) The strips I used turned out to be red/green/blue that give a "pure white" when you solder the negative cable to all three pads this can be tricky but once you get used to it it's fine (be sure to google how to solder led strips for reference)
3) I was having a problem on a strip where I had to solder two strips together to make it long enough. It turned out that the strip was folding a little on itself and the positive and negative terminals were touching. I was fortunate that my power supply had built in protection to disconnect on a short circuit or else I would have been out a power supply! The solution I came up with was to put a dab of hot glue around the solder once I was done. This creates a physical barrier between the terminals, so even if it tries to fold over, they can't touch! It also helps restore a bit of the waterproof back in the strip. Once I it had cooled I wrapped the wire bridge in white electrical tape to match my cabinets
Once you have the strips all wired up, peel off the adhesive backing and stick them in place. As you can see in the picture, I get them very near the front, but not quite all the way. They send out light at 120 degrees (normal LEDs do something around 90 degrees, and I didn't want to loose any of that light by having that lip block the light
Once they were in place and I had tested everything, I used some nail down cable clips to secure the wires to the cabinets so they didn't droop down.
Step 6: Admire the Work!
1st is the area with no light at all. It's about 2PM and I have the curtain drawn so there's still a little light coming in, but you get the idea.
2nd is the same conditions but with the LEDs I just installed lit up.
3rd is the area with normal lighting
4th is the normal lighting with the LEDs lit up. This one really shows just how bright those LEDs are!
5th is a look at the LED strip in place and lit up
Last is the a picture I took that night after the sun set with the all the lights in the house turned off