The parts are fairly cheap and the project is fairly easy. You will need to strip wires, solder leds, and be able to use a power drill. With LEDs cheap and long-lasting this project will add a warm glow to your house.
Once you have purchased the parts you need (You likely have most of them already) actually putting the bar together should take about 3 hours (if you are inexperienced).
This instructable is designed to teach with pictures as well as words. Most of the pictures have notes added to them with tips and information.
*** I am not liable for any injury, property damage, or any other losses that happen within this project. You will be working with electricity and should be careful. Though the voltage and amperages I used in this project are not harmful (or even be felt), using a more powerful electricity source, and the use of hot objects (Soldering Iron & Hot Glue Gun) can cause damage. ***
Step 1: Parts & Tools
Most of these parts were purchased at The Home Depot and Lowes.
Metal Wire Cover (Light Bar) $5.00 for (1) 5' bar. Used to keep people from tripping over wires in the home or office, I modified it to become my light bar. You could also use wood, PVC pipe, or another material. (Though I suggest something compact and tidy).
Rubber Insulated Clamps (3) $1.25 for 2 - These are used to mount the light bar to a surface.
Electrical Tape (1) $4.00 for 66' - Used to hold pieces together and insulate wires from bar.
Wet Rag - Any cloth or sponge will do, just soak it in water, its used to clean leftover solder off your soldering iron.
LEDs (18 for one light bar) $10 for 100- Pick whatever colors you want. I also suggest fading LEDS. You can use any voltage you want, though most colors fall in two categories, 1.9-2.1v(red, orange,yellow), and 3.0-3.4v (green,blue,white). Brightness is up to you, 10000mcd-18000mcd (Millicandelas) are plenty for night lighting, something like 25,000mcd may be too bright for night time, but good for accent lighting (glowing under furnitur, though 35,000mcd or higher can even be daytime lighting. Real life stores are far too expensive, so on EBay you can get them from Hong Kong for 1/20th the price. I suggest the sellers HKJE LED or LED-HK
Hot Glue Gun $5 - Get a lot of glue sticks, as they will hold things in place and insulate.
Power Supply (1) $1- Any source of power will do, though LEDs run on DC. Your voltage can be whatever you want, but you must choose your own resistors. (Supply Voltage should be higher than the LEDs Forward Voltage, around 300mA for one light bar (Milliamps are the max amount of LEDs you can have). I got three supplies for $3 at my local GoodWill charity.
Resistors (At Least 10) $3 for 100 on EBay, I suggest ResistorsPlus- These keep the LED from taking in too much electricity. It can change a 9 volt or 12 volt power supply into a 3.3 volt for an LED. For my 9 volt supply, I needed 150 Ohm resistors (9 Volts for 2 LEDs in Series). Calculate yours @ ledcalc.com A common rating is wattage, this simply means heat dissipation, you can always have the W number higher than recommended, but never lower. A higher wattage rating costs a tiny bit more, and is larger, for the most part 1/2 watt is fine, unless you begin using ultra-high power LEDs (like Luxeon Stars which can need 3-10W resistors).
20 Gauge Speaker Wire (Around 8-10 feet) - Used to connect the LEDs to the power supply.
Soldering Iron $10 (1) - Cheap, everyone should have one around. A 15 Watt iron from Radioshack works fine.
Solder (1) $3 at Radioshack- Solder with flux. I recommend silver solder at 0.022" thickness and a rosin core, it's easier to flow and more durable. Used to connect LEDs to the Speaker Wire.
Needle-nose Pliers - Used to bend LED legs.
Insulated Quick Disconnects (Optional) $2 for 12- This is used to easily plug the power supply into the light bar. You could just solder the power supply wires straight to the speaker wire, but then you always have the cord attached. (***Update, I now recommend using 2.5mm DC barrel plug connectors, they are much more durable, easier to plug in, and make a stronger connection. Buying them online is semi-random, try eBay as always**
Power Drill (1) - If you don't have one, ask a friend.
13/64" Drill Bit (2) - $1.50 for one. Used to drill the holes in the light bar. 13/64th" is the perfect size for a 5mm LED, it keeps them from going through the hole and holds them in place.
Wire Clippers - Used to cut the legs of LEDs. You can use some small scissors as well.
Awl - Something sharp with a fine point. I'm sure you can find something.
Scissors - Used to cut speaker wire and electrical tape.
Wire Stripper or Knife - Used to strip plastic insulation from the speaker wire.
If you are new to LEDs or soldering, I suggest viewing this guide @ llamma.com
Step 2: Light Bar Material
You don't have to use metal like I am, or even a wire cover. If you can find a piece of wood and drill holes through that, awesome! Plastic wire channels work even better, and are much easier to drill through. I chose this because it's cheap, I was unexperienced when I made this guide, and I wanted the bars rigid, today I suggest plastic channels, don't get the thin ones though.
For mine, it has a metal clip that is just smashed on top of the bar. Just push on it with some pliers to pop it out.
Step 3: Mark and Measure
Light Bar = 5 feet = 60".
Take off 2" on each side for the Insulated Clamps and connectors = 56".
9 Modules of 2 LEDs each = 18 LEDs.
56/8= 7" of spacing. (We divide by 8 rather than 9 because 2" is the where the first module goes).
For a light bar 5 feet long, each module should be spaced 7 inches apart. Get a measuring tape or yard-stick and with a pencil mark these slots for a 5' light bar.
Now the LEDs should be spaced 1 inch apart. So at each of the previous marks, measure 1/2" on each side and make a plus with a pencil (Try to put it near the middle of the width of the bar). This is where each LED will go.
Measure the Length of the Speaker Wire.
This is fairly simple. Just stick your wire along the bar and measure out 8 or so extra inches. These 8 inches make up for any slack within the bar, and provide extra wire to connect to power supply. When you are finished, you'll just cut off the extra anyways.
Pull the two speaker wires apart from each other, we want them to be separate (see picture).
Step 4: Measure Twice, Drill Once
Remember the marks we made on the inside of the bar? Well, take your awl (or another sharp pointy tool) and put it on the line you drew for a LED. Try to line it up with the middle of the bar and smash the awl with a hammer. Initially you should make a dent and punch a very tiny hole, later you will punch a small hole back through.
Flip the bar over, and put the awl on the new dent pointing towards you, and smash it downward to leave a bigger dent (this is thanks to metal fatigue). Hit it until there is small hole (less than the width of an LED), and use your 13/64" drill bit to clean it up.
Repeat 18 times for 18 holes, and then we will prepare the wire.
Step 5: Power
Your power supply can be from pretty much anything. An old PSU from a computer, a leftover hard drive power brick; I prefer small and compact power supplies such as those in cordless phones. Laptop power supplies are an amazing power source, they are super cheap and available, usually can supply 3-5 amps (which means a max of about 230 LEDs), and are regulated [which are normally super expensive] at 12v DC. No matter what the plug on the end is, you can bet there are two wires in there: Positive and Negative.
I obtained three 9 volt power supplies at my local goodwill for $3. eBay also has a plentiful selection of power supplies, though it will take some searching. The supply needs 350mA or more to power 18 LEDs. mA determines the maximum amount of LEDs. 99% of 5mm LEDs use 20mA each, so just multiply the number of LEDs by 0.020A (18 LEDs * 0.020A = 360mA, which is technically overloading it, but it still works).
The speaker wire will carry the electricity from the power supply wires to the LED wires. Decide right now which of your two speaker wires will be your positive, and which will be your negative.
As a general rule, the red, yellow, white, or lined wire is the positive, while the solid (usually black) is negative. After the next step, you will have two LEDs and a resistor soldered together. Just try touching them both to the speaker wire, whichever lights up for you is your correct solution.
This step is optional. It makes it easy to plug and unplug the light bar from the power supply. If you don't want to use Quick Disconnects and want the power supply always attached, just twist the wires of the speaker wire and the power supply together and solder them. Wrap them with electrical tape to keep anything from shorting out.
Quick Disconnects have a wire going into them, and usually you just crush it with pliers (Called crimping) and the wire stays in place. An optional purchase to skip this awl & solder method is a pair of crimping pliers. Regular pliers were incapable of doing the job for me, so I pierced and soldered them into place. Knowing from experience now, I strongly recommend just buying crimping pliers than this next awl + solder method. If you don't feel like spending money, then go for this method, which actually is a stronger connection than crimping alone.
Because its not possible to stick solder into the Quick Disconnect (its covered in plastic) and melt it and the wire together, you should coat the end of your wire with solder. Stick the wire into the quick disconnect. Now hit the Awl on top of the Quick Disconnect, this will pierce the casing and squish the metal and wire together. Follow it up with sticking the tip of your soldering iron into the hole to melt the solder. You should have a very solid connection between the wire and Quick Disconnect. Finally, wrap any exposed areas up with electrical tape.
Step 6: Snip, Sheath, & Solder
Use the pictures as a guide.
Soldering LEDs Together
Bend the legs of each LED to 90 degree angles. Clip the front positive leg so it is short , this is where the resistor will be attached. These are wired in a Series, meaning the LEDs legs meet back to back (postive-negative-positive). See the diagram for a visual illustration.
Set the LEDs into the drilled holes, as this keeps them aligned and pointing in the same direction. Make the legs meet, and touch the soldering iron at the meeting point. Touch your solder to the legs, and it should melt onto the legs binding them together. Now bend the front positive leg into a U shape, repeat for the resistor. This hooks them together and makes it easier to manage. Solder them together.
Soldering LEDs to Wires
After the resistor has been attached to the front positive LED, remove sheathing from the positive speaker wire, and solder the leftover resistor leg to it. Then remove sheathing from the negative speaker wire, and solder the negative LED leg to it. You can now test if your LEDs light up by plugging in your power supply.
Securing/Insulating with Hot Glue
Place the LEDs and the newly attached wires into the bar, and the LEDs go into the holes. Make sure that no LED legs or exposed wire is touching the bar. The LEDs and wire will naturally want to move around, so press the LEDs down with pliers so they are flush with the holes, pour on a lot of hot glue, and wait for it to dry.
Repeat this step 8 more times, and then its time to finish everything up.
Step 7: Finishing Up
If everything is set on your light bar, snip off any extra cord handing out the back end. Wrap the end with electrical tape just to keep it together.
If you find yourself making a lot of these, a step I don't cover is called daisy chaining. Basically you put quick disconnects on both ends, so it can be powered on via either side. Then you make a short (3 inch or so) connector cable that plugs the light bars into each other end to end, this chain can go on indefinitely. If the quick disconnects on both sides of the light bar are female plugs, then your connector cable would have male plugs on both ends of it.
Put the slide back into the bar, closing up the light bar. Reinsert the friction clip to lock the slide in place. And the light bar should be completed. Now you can choose where you want to put the bar itself.
This is where the Rubber Insulated Clamps come in. I like to use screws, however nails are equally good. One clamp goes in the middle, and two on the ends. This is why we saved 2" on each end of the light bar, making it easy to attach to a surface. Pictures show how it can be done.
This is a step you can use to change the appearance of your LEDs. If you feel that your LEDs are too bright or shining too strong of focused beams, you can sand the tops of the LEDs to more evenly diffuse the light. Go purchase some very fine (600-1200grit) sandpaper and just rub the top of each LED. you should have a smooth blurred LED, and this will scatter the light more effectively.
Step 8: Mounting the Light Bar
I've put some behind my couch so beams of green and blue lights shine out of the back. We also screw them into the ceiling to shine down the walls for our primary lighting in our house. For LAN parties (with the red and blue rooms of the house, each with red and blue LEDs) we place them in the corners to shine along the walls for each team's room color, and green LED light bars signify the neutral room with all the food and drinks. Use your imagination to place these bars, especially with the use of refractive (glass) or reflective surfaces.
This guide was focused on a 5 foot bar, but any size will work. If you have any improvements upon my methods, or great ideas on how to use a light bar, feel free to leave a comment.
Happy lighting - QuackMasterDan.