Introduction: Under Cabinet Lighting

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Like many people, the counters in our kitchen never seem to have enough light on them.  This isn't too surprising since we have a single light fixture by this area and we block it every time we want to use the counters!  After looking around it became abundantly clear that traditional under cabinet lighting was *way* to expensive and too large.  The recess under the cabinets are less than an inch deep (~3/4 of an inch).  There are decorative solutions around that, but that just drives the cost of the project up higher!  The ultimate solution came in the form of waterproof 5050 LED strips with 3M adhesive backing.

Step 1: Gather Your Materials

This projects requires some soldering (at least the way I did it).  I've seen people get by with hot glue but I'm going to assume that you are comfortable with a soldering iron so there won't be a lot of details on those parts (there are lots of great instructables on how to solder if you want to brush up on them).

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

First up you need to measure the amount of under cabinet space you want to put these lights on.  When I first started this project I though I would need two rows to get enough light, but by the time I was done it was clear that a single strip placed near the front of the cabinet was all you need that covered the entire length of the cabinet (or close to there) was more than enough!

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

Next you need to get power to the AC adapter.  If it works for you to just plug it into an available outlet and put an in-line switch on it, that is all you need!  I wanted something a little fancier though.  I already had an over the sink florescent light that is controlled by a light switch.  After turning off the light switch and confirm that that killed power to the cable, I cut the line and did an in-line solder to reroute the AC line to the top of my cabinets.  I placed a junction box up there and sent a cable back down to my light to provide it power and after cutting off the AC plug on my adapter I used a twist cap on all three sets of cable to power my adapter.  I suppose I could have just as easily put a power outlet up there, but I liked this on better.

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

One thing I read about these strips is that they can suffer from voltage drop over the course of the strips (meaning the lights at the end of the strip may appear dimmer than the ones at the beginning).  Now this might have been talking about longer runs than I was going to do, but just to play it safe, I made sure to send one pair of wires to each strip rather than going from strip to strip.  It took more wire, but I think it was worth it.

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

I'm afraid I didn't get a shot of this process, I was rather busy at the time but there's a couple things that I found very useful through this process.

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!

Here's some pictures of the final project.

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