LED Lighting DIY for Ikea Detolf Cabinets

Motivation

I knew right from the start I wanted to LED light my detolf cabinets after seeing so many impressive setups on the tfw2005 forums.  I also knew I wanted to do it cheap, and that doing it via a DIY path was viable for me.  Looking at other people's installs, the devil is in the details and often people would skimp a bit on the tidy side of the wiring, and people also weren't very specific in their descriptions of their builds!  So I had the idea, but no build details.. so here is my write-up of my install for future buyers :)

LED Source

This is driven by personal choices and availability more than anything.. but there are some basics.  

• Single color vs RGB - This is a cabinet display, so I knew I didn't need the ability to change colors except for 'just because I could'.  Single color is also only 2 wire, where RGB is 4 wire.  2 wire was going to be much easier to install and smaller to hide cables... so Single Color it is!
• Warm White vs Cool White? - You can find a natural color 'warm white' if you desire.. but since we are playing with toys here, I want the higher tech looking cool white
• 3628 vs 5050 - The numbers refer to the actual LED size 3.6mmX2.8mm vs 5mmX5mm.  Again because we are going for tidy... I wanted the smaller LEDs.. so 3628 it is.  3628 strips are 8mm wide.  5050 can be brighter, but also take more power and larger.
• High Density? - The strips normally come in 300 LEDs per meter or 600 LEDs per meter (high density).  In theory more LEDs = more light.. but it depends on the actual components used.  Try to look for luminance specs when comparing products.  In my samples, I actually preferred the light output of my 300 LED strip over the 600!  The other advantage of high density is the points where the strip can be cut and joined are more prevalent.  In my samples, the 300 strip could be cut every 3 inches, the 600 was every 1 inch. In my install, the trimming was not a showstopper.  

My conclusion was to use a 3628 cool white strip with 300 LEDs per meter.  Source - Amazon - http://www.amazon.com/gp/product/B005EHHLD8  $8 with prime shipping.

Note this strip is a 'waterproof' strip.  Waterproof obviously isn't needed, but I didn't notice it when initially ordering, but now that I have it, it was ok and I didn't mind it.  In some sense, it helped support the strip making it easier to work with and diffuses the light some.

NOTE:  These kinds of products can change components and be slightly different from different sources.  The strip I purchased had wide angle LEDs, and when purchased again from a different seller, the LEDs were different.  So be careful if buying at different times.  I bought the item sold by Amazon directly and I was happy with that set (twice).

Power Supply

You can use any 12V power supply with enough power to drive your load.  The load is specific to your wiring layout and LED choice.  Amps = Watts / 12V 

I wanted to run everything from a single power supply so it could be controlled from a single controller.  I calculated the theoretical load for my wiring and LEDs as 1 Amp @ 12V per cabinet.  Since I was doing two, and wanted plenty of head room, I got a 5A supply.  A single cabinet could be done by a 2A or 3A supply easily.  My 5A supply - $17 from Amazon Prime - http://www.amazon.com/gp/product/B00PK0N14M  5A power supply with 2.1mm plug

Wire

Approximately ~20ft of 20 or 22 awg stranded single conductor wire per cabinet is needed. Here you can go multiple ways depending on what you have available.  Ironically this was the hardest part to source!  You want smaller wire to make it easier to hide.. any 20 to 24 awg stranded should be fine for this load.  Home Depot/Lowes won't have it, but Train Hobby Stores will and call it 'Layout Wire'.  My preference was black wire for the jumpers (you'll need about 2ft per cabinet) and white for the cabinet wiring.  Worse case you can use 18" speaker wire, but it's a lot more bulky and hard to hide/bend.  You may also find red/black speaker wire in smaller sizes, but will be harder to hide.  Once you find the correct cable, you should be able to get a spool of 50 or 100ft for ~$8-12

Other Misc parts needed:

Wireless LED Controller - I didn't have a switched outlet handy, so I wanted a remote power switch.  This fit the bill and has other features like dimming!  This is the version with 2.1mm plugs already attached - $6 from Amazon Prime - http://www.amazon.com/gp/product/B00MHKCTLE 

Clear/White Wire Ties - Get a bag of the smallest tie size you can.. Usually about 4"  ~$4 from your home improvement store

Wire Shrink Wrap - ~10 inches of 1/8" heat shrink colored to match your cabinet wiring.  I just bought a big box of everything from Amazon Prime to replace the leftovers I was using - $12 from Amazon Prime - http://www.amazon.com/gp/product/B000FIDTYG 

The following components could be made redundant if you hardwired everything, but I opt'd using these so it could be plugged/unplugged in pieces.

Power Plug Adapter - These make the wiring easy and are useful for quick testing too. The build needs one per cabinet.. A set of 10 is only $3 - http://www.amazon.com/2-1mm-5-5mm-Female-Power-Adapter/dp/B003MHUN7S

Power Splitter - Since I was doing two cabinets.. this splits the power supply to two 2.1mm male jacks.  You can get higher #s of spliters if you need to do more cabinets and your power supply is strong enough. - 1 to 2 splitter $4 with Amazon Prime - http://www.amazon.com/gp/product/B007Q8IKRE 

Single color LED Wiring Connectors - In the spirit of pluggable, I ordered these as well, tho in hindsight it might be advisable to skip these.  I'll cover that at the end.  This guide is written assuming you are using them.  Pack of 10 $7 from Amazon Prime - http://www.amazon.com/gp/product/B00LGK8FL4 

Tools

• Soldering Iron + solder
• Razor Blade
• Wire Cutter and Wire Stripper that can strip 20-24 awg wire
• Electrical tape
• Scissors
• Small Precision screwdriver
• Small needle nose plyers
• Diagonal cutters or similar nub cutters
• Hair Dryer, lighter, or torch to shrink heat shrink
• Scrap cardboard.  One piece for cutting with the razor blade, another roughly 2'x2' for making a template

Design

The driving factors in my design was 1) sufficient, even light  2) clean look - hide wiring as much as possible 3) Serviceable if need to deal with failures/dis-assembly.  

In researching other people's installs I found where the lights were installed varied, but taping directly to the glass shelf was more common than I expected.  I originally thought I would connect to the shelf bars, but I abandoned that once considering how to keep them aligned, stuck, and still look tidy.  In what order, lengths, etc where the LEDs connected was a topic not well covered in other people's pictures.  

In the interest of minimal cabling I went for a 'common bus' design.  One set of wires runs the full length of the cabinet, and each shelf has a string of LEDs that taps into the common bus.  This design puts a series set of LEDs per shelf, in parallel with the other shelves.  

Each shelf has three LED strips wired together to go around the edge of the shelf, and the set is connected to the common bus wires running the length of the cabinet.  The bus wires are terminated with a 2.1mm adapter for easy plug/unplug, which is connected to a 2.1mm splitter so multiple cabinets can be fed from the same power supply.  The power supply is connected to the LED controller, which is in turn connected to the splitter.

Build

Each shelf in the cabinet is the same, so my design uses the same setup on each shelf, including the cabinet top, to ease the build.  The LEDs go along each side and the front of the shelf.  Make note of where your LEDs can be cut - there will be small pads and lines to show where you can cut the LED strips.  The LEDs can be cut with simple household scissors - make sure you cut in the middle so the pads left on each edge are as large as possible. 

Layout the LEDs on one of the shelves and cut three strips to mock up how they would lay out on the shelf if attached to the underside of the shelf.  For the LED strips I used, this resulted in a 11.75" strip for the front, and 9.75" strips for the sides. In my layout, the strips are about 3/8 of a inch inside the shelf supports, and about 0.5" from the front of the shelf.

Make note of which side of your cabinet you want the common bus wires and connects to be.  I chose to run them on the inside edge of my cabinets to try to make it harder to see.  Measure the glass shelves' length and width dimensions.  Note where the inside edge of the bar supports are relative to the shelf edge.

Use some scrap cardboard as a cutting board, take your three cut LED strips, and using a razor blade, trim the waterproofing off the end of the strips.  Cut the vinyl material back to a point near the first component on the strip.  Slice through the vinyl portion being careful not to cut the strip itself, and pull the waterproofing off.  Make a cut, bend back, repeat, etc.  You can try to get under the edge and separate it, but I found just making a vertical cut, then bending and working the cut till you get separation and you can tear the piece off

Because all shelves are the same - it makes sense to use a template to ease your build.  I just used the bottom of the Amazon box my stuff came in!  Transfer the dimensions of the measured shelf to the cardboard and draw out your shelf.  

Next, layout your trimmed LED strips as you will want them to be on the shelf.  Lay them out with their backing down, LED facing up.  This is the layout if you were looking the shelf from the bottom.  If your bus wires will be on the right side of your cabinet, they will be on the LEFT REAR side of your template because you are looking at it upside down.

If you will be using the wiring connectors, they need about 1/4" clearance on the strip to connect to the strip.  On the LED strips I used, a diode near the edge of one side of the LED cutting points meant only one side of trimming point had enough clearance to use a connector so you had to orient the strips a specific direction.  If the power is on the LEFT side of your template, orient the LED strips so the + pad of each strip is to the middle of the shelf.  This should put the edge WITHOUT the diode near the left rear of your template.  If your power is on the RIGHT side of your template, orient the strips with the - pad to the middle.  Again, this should result in the LED end with the most space being the end near your power corner.  Each LED strip should be laid out so the + and - pads are on the same side of two adjacent strips.  

With the shelf marked out on the template, arrange the LED strips as you would have them on the shelf.  Use strips of electrical tape right over the top of the strip to help you make the layout.  In my setup, I arranged the three strips so the side strips ended slightly before the inside edge of the center strip, and the entire assembly would align so the wire connector on the power side would be right inside the edge of the shelf.  This resulted in a layout where the center strip was approx 1/2" from the front edge centered left to right, and the side strips were oriented approximately 3/8" inside the shelf supports.  You should be able to make L shape lines between the like +/- pads on adjacent LED strips.  Use one of the wire connectors to help you gauge where the power side should end so the connector is still 'on' the shelf.

Corners arranged

Connector staged to place the strip at the correct location

Once you have the layout as you want it, use a pen and mark on your template the + and - symbols near each edge to help remind you, and mark around the edge of the strips near the joints so you can easily align the next set of LED strips.

Template notes to help arrangement - Note, + or - locations will depend on which side the power connector is wired - don't follow this example blindly :)

The photo below is an example template with power connector on the RIGHT, so - is to the inside.  Note each LED end has lines around it, the - and + symbols to help, and the electrical tape holding things in place.

Using the soldering iron, load up each strips' pads with solder.  Do NOT put solder on the ends connecting to the wire connectors, only the joints between the center and side strips.  Just place the iron on the pad, and touch some solder to the point and create a small ball.  Don't worry about sloppy here, just don't short the pads together or have huge spikes of solder poking out.  

Next you will have to connect the + pad of the center strip to the + pad of the adjacent strip using a small jumper wire.  Do the same for the - pads, and then repeat for the other side of the center strip.    Start with the inside pad, and then repeat for the outside pad.  

To make the jumper wires, cut a small portion of your layout wire, shape it into the L shape needed to fit between the pads.  I recommend cutting the piece about 1.5" long, then trim about 1/4 of the insulation off one end with your wire strippers.  Twist the exposed wire to tighten the strands, then trim the exposed wire to about 1/16" long.  Lay it on the template, and bend the wire to layout between the LED strips.  Trim the wire long, strip the insulation back about 1/4", twist the wires, and again laying the piece on the template, trim to final size needed.  Keep it a little long and trim as needed.  Repeat this till you have a jumper that lays between the pads well.

Hold the jumper with a pair of needle nose pliers, melt the solder on the pad, and solder the wire to the pad.  You won't get beautiful joints because of the pads, but it will hold very strong.  Just try to keep the wire from spreading out or shorting to the adjacent pad.  The wire should have good contact with the pad and the pad should move in unison with the wire when moved.  Then repeat for the other side of the wire.  Install all four jumpers needed to connect the three LED strips.

These photos show white jumpers - I experimented with both white and black and found black to be preferable as it tended to draw less attention to them once installed.

Here is a view of black jumpers, installed in the cabinet

Next you will need to test the strip.  If your strip has the power on the left side of the template, grab a wire connector and find the end where clasp opens on the red wire side (if power is on the right, use the side with clasp on the black side - you want the clasp opening on the 'inside' of the shelf).  Measure back 3" from the connector and cut the the other end of the connector off.  Split the wires, and strip the insulation back approx 1/8".  Use one of the female plug 2.1mm adaptors and screw the adaptor onto the connector.  Use this connector+adaptor as your test plug to test each shelf unit as you build them.

On the LED strip where your wire connector will attach, pull back the adhesive tape cover on the bottom of the strip where the weather proofing has been removed and trim it.  Only remove the cover where the wire connector will be.  Open the clasp of the connector, insert the strip so the prongs make contact with the exposed pads on the strip, then close the clasp.  Plug the strip into your power supply and it should all light!

If no strips light, ensure the wires at the power adapter are secure and in the correct slot.  Check the wiring connector and ensure it's making good contacts with the pad.  If one strip doesn't light, first double check the + goes to + and - to - between each strip.  Press and/or move the strips around to see if you have a flaky joint.  Unplug the strip before making any corrections by re-soldering the jumpers in question.  Ensure all three strips light reliably and then take the set to your cabinet and lay out the set on the top side of a shelf, LED down and ensure it lays out as you want.  Try to avoid stressing the jumper connections when possible.  If you are not happy with the layout, make any adjustments to your template needed to guide your next sets.  You can remove the wire connector from the strip and use it again when testing other sets.

If you are happy with your first set, then using your template, make three more sets of the LED shelf sets.  The lines and +/- symbols you drew on the template will speed up the additional builds and ensure consistency.

Stage the Wire Connectors

The wire connectors provide a way to disconnect the shelf sets from the common wiring if need be for adjustments/fixes.  If you bought the back to back ones linked above, you only use one side of the connector for each shelf.  But which side you use matters.  You want to use the side where the clasp will open from side AWAY from the side of your cabinet so you can reach it.  Using your template as a guide, determine which side of the connector you will use so it matches the desired clasp direction and LED + / - pads.  If you can't get the pads to line up, red to +, black to -, don't worry about it you can ignore color as long as you are consistent when you wire everything up.

When connecting to the common bus, we will stagger the joints to minimize bulk.  In my design, for the wires coming from the connector, I left 0.5" to account for the bend, put the first joint 1" down, and the second joint 2" down from the connector.

Make a simple template.  On your scrap cardboard, draw a line marking 0, 1.5", 1.75", 2.5", and 2.75" lengths.  Grab a connector with the end you will use, lay it on the template it so the back end of the connector where the wire starts lies at the 0 mark, and cut the wires at the 2.75" mark.  Using your razor blade, split the black and red wires and pull them apart.  Pick one color to be the long wire - you will use this same scheme for all your shelves in this cabinet, so be consistent.  Using your template, strip 1/4" of the end of the long wire, and twist the strands.  Trim the other wire to the 1.75" mark, and then strip 1/4" of the wire and twist the strands.  You should have a connector with a 2.5" of covered wire with an extra 1/4" of bare wire, and the other lead 1.5" of covered wire with an extra 1/4" of bare wire.  

Repeat the process and make three more connectors.  Be sure to be consistent with which way the clasp opens, and which color wire is the long and short wire.  Check things against a LED set on your template if you need to double check stuff.. remember.. the cardboard is the BOTTOM of your shelf, so the clasp should open upwards and from the middle when sitting on the template.

The bus wires

The bus wire needs to be >65" to run the length of the cabinet.  I recommend starting with a longer wire, you can always trim shorter.  Cut a piece of wire approximately 85" long.  Trim 1/4" of the end of the wire.  Cut a piece of heat shrink about 5/8" long and slide onto the wire.  Take one of your wire connectors, with the long wire, and shape the bare wire into a hook shape (wrapping around the shaft of a small screwdriver is a quick trick!).  Do the same with the bus wire, then loop the two wire hooks together, then twist them tight.

The joint should support itself.  Solder the joint securely and allow it to cool.  Then slide the heat shrink over the joint and shrink using a hair dryer, lighter, or torch.  Be careful not to burn the wires if using an open flame.  This will be the joint for the top of the cabinet.

Each shelf is 15.5" apart, and it's 15 1/8" from the top of the cabinet to the bottom of the top shelf.  Each joint will be 15.5" apart, and the first joint will be 15 1/8" from the start.  Because the of the lead on the wire connectors, the joints will be 1" and 2" below the shelf itself.

On your long bus wire, measure 15 1/8" along the wire from the solder joint and using your wire strippers, split the wire insulation and pull the insulation back to create a bare spot in the wire WITHOUT cutting the wire.  If you use wire strippers with the correct size for your wire, this is trivial.  Just cut and then tug on the wire to create a gap.

Take one of the staged wire connectors, lay the LONG wire along the bus wire with the bare end pointing away from the previous joint you just made.  Take the bare wire of the LONG lead and wrap tightly around the bare spot created on the bus wire.

Solder the wires, and allow to cool.  then cut a piece of heat shrink about 1/2" long, slide over the end of the bus wire and up over this joint, including where the wires lay parallel to each other.  Shrink with heat.

Repeat the steps for two more connectors.  Measure 15.5" down the bus wire from the solder joint (not from where the heat shrink ends - from the joint!), and repeat the process.  Split the insulation, lay out the LONG lead of a staged connector, wrap it, solder it, then cover with heat shrink.

Cut a second wire approx 86" long to act as the second bus wire.   Cut a piece of heat shrink about 5/8" long and slide onto the wire.  Strip 1/4" from the end of the wire.  Shape the bare wire into a hook shape.  Take the remaining short lead from the top most wire connector, form the bare wire into a hook, loop the two wire hooks together, then twist them tight.  Solder, and then shrink the heat shrink over the joint.  

The trick with the second wire is ensuring the wire connectors and bus wires are not twisted or crossing so they lay nicely when installed in the cabinet.  When connecting the wires of a connector, we need to lay the cables and connectors out tidy to ensure we don't introduce twists between it and the previous connector.  Grap the top most connector, lay it so the clasp is facing up, then layout the bus wire to the right until you get to the second wire connector.  Orient the second connector so it lays to the left along the bus wire, pointing at the previous connector, clasp up,  and the leads not crossing/twisted.  Now take your second bus wire, stretch it out and lay it along side the first bus wire so it lays flat and does not cross the first wire.  At the next connector, the goal is to have the connector pointing to the left, laying flat on the bus wires, clasp up, and no crossing of the leads.  

It should look like this diagram

With the connector and wires laid out, mark where the bare wire of the first unattached short lead crosses the second bus wire.  Using your wire stripper, split the insulation and expose a small gap.  Twist the bare lead of the connector onto the wire and solder the joint.  Cut a piece of heat shrink about 1/2" long, slide over the end of the bus wire up over the joint and shrink with heat.  Repeat this process for each of the connectors.  You do not need to measure distances as long as you layout the wires flat and oriented correctly.

An example of a completed wire connector joint

Now connect a LED shelf set to each of the wire connectors.  Pull back and trim the 1/2" or so of tape backing cover on the LED strip where the connector will attach.  This will make the set easier to install in the cabinet.  Open the clasp on the connector, slide in the strip making sure the pads make good contact with the prongs, and then close the clasp..  Once all are connected, strip 1/4" of the end of the bus wires and connect a 2.1mm female adapter.  Connect to the power supply and check that all LED strips light reliably.  Adjust any wire connectors or jumpers as needed to get the full set to light reliably.  This is also a convenient time to test your LED controller!

Install into cabinet

Empty out your cabinets to give yourself room and to avoid risking dropping anything!  With the full set complete, run the set of wires down the back of the cabinet by dropping them behind the shelves.  Starting at the top of the cabinet, test fit where you want the LED strips to be to mounted to the top of the cabinet trying to be uniform in layout and positioning so the wire connector aligns near the shelf supports and along the back edge of the shelves.  Starting at the wood top, remove the backing from the LED strip one at a time, and press the strip into place.  Repeat for all three strips and press firmly into place.  Make sure you don't create any binding in the corners.  You may need a short piece of electrical tape to hold the wire connector to the top temporarily to help keep it from pulling the rest of the strip down while doing the initial install.

Once the strips are attached, run the bus wires down behind the wire posts of the cabinet, using wire ties to organize the wire as you move down to the next shelf.  Avoid twists, and don't tighten the ties until you have mounted the next lower set of LEDs so you can shift the ties as needed.  I used 3-5 ties in-between each shelf.  I also used ties right under the wire connector to help support it's bend.

A look at the wire ties (final install)

Continue moving top to bottom, aligning the bus wires, then attaching the next shelf of LEDs, and repeat.  Once a shelf is installed, it helps to tidy up the wires above it and tighten the wire ties.

Once you get to the bottom shelf, you will need to run the bus wires out of the cabinet.  In my case, I chose to simply drill through the the bottom shelf and run the wires out the back.  I have the plastic feet on my cabinet, and they take up >1" in radius around the post supports, so you can not drill directly near the wire posts.  Instead, I moved approx 2" to the inside from the wire post, and drilled a 1/4" hole through the bottom of the cabinet.  The minimum size how you need will depend on your choice of wire.  Vacuum out the dust created.  I also painted the hole with semi-gloss black paint to help make it disappear.  While you have the paint out, it is useful to paint the front edge of the cabinet where the crappy laminate doesn't cover the wood on the seams very well.  Brush on the seam generously, then a quick wipe with your finger will remove the excess leaving a perfect look.

Pass the bus wires through the new hole, and use your wire ties to get the wire as in conspicuous as possible.  Trim the wires to the length desired depending on where you want your 2.1mm plug to be.  Strip the ends of the wire, and attach a 2.1mm female power adaptor.  Connect to the wire splitter if needed, then into the LED remote, and then the power supply.  Light it up, and tidy up the wiring to your taste!  If the lights don't work, try flipping the bus wires in the 2.1mm adapter.

Here is the white wire through the bottom of the cabinet up close

Finish up your job by clipping all the wire ties close and adjusting the locations and rotation to hide your bus wires as best you can and cleaning up the glass anywhere you put your finger prints on :)
 

Some final views

Retrospective and Improvements

What would I change in hindsight?  First, while the wire connectors were chosen for serviceability, I don't think they are worth the trade-off in reliability.  They can be a source of unreliable connections making a shelf flicker, and aren't as easy to attach while in the cabinet as I would have hoped for.  I would suggest substituting the connectors with simple hardwired leads between the LED strips and the bus wires.  Instead of a 2.75" and 1.75" wire leads on the connectors, add another 1/2" of length to a wire and attach the LED strips via these jumpers to the bus wires the same as you connected the wire connectors.

Wire?  I found the black wire better to be better for the jumpers between the strips, but was mainly indifferent when it came to the bus wires.  Black or white would do.   20 awg was more than large enough, if I could find smaller wire, I would have used it.

Bus Design?  Worked like a champ and would highly recommend it as a wiring setup for these cabinets.

I actually used laytex gloves when installing into the cabinet to minimize how many fingerprint/etc I got on the glass I had to clean up.  When vacuuming the dust from drilling is also a good time to vacuum any dust from the cabinet as well :)

Power choices?  Using the 2.1mm adapters and splitters was a great choice and having the box of adapters made testing things SOOO much easier.  The LED controller did not work with the first power transformer I had, but worked fine with the one I bought.  No idea why.. but having it all working via remote and easy 2.1mm adapters is very much recommended!

Total Cost for two cabinets?

$8 x 2 for LED reels

$10 for Spool of Wire

$17 for Power supply

$3 for 2.1mm adapters

$6 for LED controller

$4 for 2.1mm spliter

$7 for Wire Connectors

$12 for shrink wrap

$4 for wire ties

= $79 / 2 = $39 cabinet.  It would only cost about $12 more to add a third cabinet.  And could be as cheap as ~$15 /cabinet if you had wire/shrink wrap handy and hardwired things.