How to Get High Quality LEDs for Pennies





Introduction: How to Get High Quality LEDs for Pennies

About: I'm an Electrical Engineer who dabbles in just about everything. By trade, I'm a controls engineer and design machines for the largest manufacturing plants in the world. At home, I make a lot of embedded sys...

Update: When I published this instructable years ago, LEDs were quite a bit more expensive than they are today. If you find yourself with a tangled up set of Christmas lights, this may be a good way to salvage them. With the current cost of LEDs, the only reason I would recommend grabbing a set of new lights to cannibalize would be if you like/need the shape of the diffusors for an aesthetic purpose. One of the best ways to buy LEDs (IMHO) is Ebay. If you go with an international seller, just know that it may take a month to get your LEDs through customs.

Lets face it, electronics aren't cheap. High quality, high brightness LEDs are expensive and hard to find most places.

I have a solution. How about great LEDs that only cost 6 cents a piece new?

Wait until after Christmas and bombard your local hardware store for their "after-Christmas Clearance" sales. You can find strands and strands of LED Christmas lights for 75% off normal, which means you spend about $3 for 50 LEDs. That saves you about $22.5 if you were to buy similar LED's at online retailers. Your LEDs cost you 13% of what they would before. 6 cents for mine vs $1.50 retail.

I like to do things visually, be sure to look at all of the pictures and the image notes for in depth comments and hints to make your life easier and this instructable better!

Step 1: Materials

 Alright, this is what you'll need:

-LED Christmas lights
-Electrical tape
-Power supply
-2 large coins

-Wire strippers
-Time, lots of time......

Step 2: Prepare the Strand

Take the strand out of the box.

If you lay out the chord and look closely, you'll find a few LEDs with three wires sticking out.  Because LED's can only use electricity running one direction, and AC current (what your wall outlet puts out) runs in two directions.  Two of the wires on the LED are directly connected as to let current flow backwards through another set of LEDs and allow the LEDs to function.

These LEDs don't let us unravel the LEDs from the rest of the strand very easily, so we'll need to cut off the outlet/plug as well as the 3 wire LEDs. Set them aside, we can use them later.

Step 3: Unravel the Strand

 This seems pretty self explanatory, but let me give you a few hints:

-Unravel the single LED strand from the two power strands - it makes for less tangles
-Keep tidy...bundle and tie the LED strand as you go, also makes for less tangles
-Don't pull, twist apart the strands...again, this will lead to less tangles and knots

You will reach another two or three 3-wire LED's along the way, so keep those wire strippers/cutters out.

Step 4: Cut and Strip

 To make a good finished product, you should cut as close to the middle between the LED's as you can.

It might be smart to leave some of these LEDs in sets of 3 or four in case you need them for a later project that way - it saves time by not having to solder together strings of lights.

After you get all of the LEDs separated, you'll need to strip the sheathing off the wires.
A good rule of thumb is to strip off one half the diameter (ie the radius) of a penny.  This will give you plenty of extra space for twisting, soldering, or what ever you'll be doing to the wires.

If you plan on using these on a breadboard, you'll either want to strip less off (see the next step) or solder on a solid core 22 GA wire.

Step 5: Do the Twist!

 No, no, not the dance.  To keep things tidy in storage and in use, we need to twist the ends.

This will also make it easier to use with breadboards as well, though you might want to cut them shorter to make it easier.

Step 6: Test the Leads

 LED stands for Light Emitting Diode.  A diode is an electrical component that allows electricity to flow in one, and only one direction.  As a result, LEDs will only work when electricity flows in a specific direction.  This step will help you label your LEDs so that you know which way to use your LEDs in future projects and save you time.

I'm using my Arduino Mega fed by a wall-wart as a power source.  With my particular LEDs, I don't need to use resistors with my power source, but you should use resistors between your VCC and your LED.  

To make testing the LEDs easier and faster, I've wrapped and taped wires around two US quarters (any large coin will do) to give me a larger contact points.  One of the wires has been labeled with a white bit of electrical tape to signify it is the VCC and the other is the ground.

You'll need to test every single LED and put a small piece of white electrical tape around the positive lead.

Step 7: Finished Product Demo Video (Shiny!)

 Alright, here is a demonstration of the LEDs in action on my Arduino Mega micro controller.  Nothing too fancy - I just finished putting together the box this morning.  This is the test sketch to make sure that everything is working correctly..  Enjoy!



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    32 Discussions

    Sadly, Radio Shack pretty much concentrates on beginner electronics, anyway.
    Advanced stuff is just not stocked.

    I Think is a great idea, except that in Oz, they are still dumping incandescent product on us.

    nice post!...

    Im interested in the end project. What did you use to control the leds?

    seemed like there was too many leds for the MEGA alone to control?

    Did you use some sort of shift register or something?


    I'd just like to say that blurry photos and all, this is a fantastic Instructable and very well written. Extremely simple and helpful. thanks.

    I've done this before... it's a lot of work. The more practical (time wise) application is to KEEP the light string intact... and get an AC relay switch to cycle the whole thing on and off. Then you can use the light strings as part of an (for example) Arduino LED lightshow (keeping in mind that the relay would not let you control individual light bulbs, but that's fine if you want to manipulate several strings individually).

    Agreed with some other commenters that this may not be the cheapest way to go - but they have a rugged housing and nice stranded wire already terminated to the leds with resistors built in...saves a lot of work in the long run for a lot of types of project.

    Great writeup; shame some of the pictures turned out blurry.

    3 replies

     Sadly, as a college student, I can't afford a nice camera...I used the camera on my phone :)  Thanks for the complements, and criticisms, as well :)

    You would be surprised how great cellphones are for pictures, "if" you make a tripod for it. This is even more true if your camera has a "delay picture" feature (so that while taking the picture you do not move the camera any).

    Velcro brand hook and loop is one of the best materials for turning a camera into a tripod. You can use anything as a weighted base.

    Even if your camera lacks a timer delay for taking pictures, the tripod is totally worth it (and perhaps it would make for a good Instructable... hmm...)

    These probably work best around 3.8V. I've had these running directly off of 5V for a while, and some of them are starting to go bad. For short term use, 5V gives you really great brightness, for anything you plan on using for a long period of time, I'd recommend you add some 120 ohm resistors.

    I would like to make an addition to this.  Some LED bulbs are indeed 100% removable.  Also, you can sometimes get only orange LED's in the same way for after Halloween sales.  I myself got over 600 orange LED's for just about $8.  You can pull them out like normal Christmas lights and bend the LED leads back from the special plastic insert, and pull them straight out.  Time consuming, but hey, pennies for LED's.

    2 replies

     What brand were they?  Do you remember? I grabbed the button ones because they looked removable, shame they weren't.... 

    Sorry for taking so long, they weren't a specific brand. They were generic "Target" brand. Yeah, orange box, retro-simplistic styling.

    Should have thought of that... Until I just saw this. At least I learned were to get LEDs for cheap!

    Darn. Just stumbled across this again -- I was meaning to pick up some of the leftover LED lights in January, and completely forgot. Next year, maybe. This isn't necessarily the cheapest way to get 'em, but it's convenient.

    1 reply

     Just keep in mind that it does take a while to clip and sort through a few hundred of these things.  While they are pretty hardy little LED's, they aren't very convenient :)

     Are They DC, i haven't ever had LED Christmas lights so i don't know if there is and adapter or not.

    2 replies

    LED's, by definition, only allow current to flow in one direction.  They will work in both AC and DC circuits, but read below.

    A DC source is one that flows constantly in one direction. If you have them connected to a DC source, the direction of your LED is correct, and the power us under the threshold, they will work just fine. 

    AC sources are a different story.  AC stands for "Alternating Current" which means your current oscillates between a high and low according to a sin wave.  If your high is positive, and your low is negative, your LED will flicker on and off with the period of your sine wave. If your high and your low are both positive or both negative, your LED will throb with your sine wave.

    Another important thing to know, is that if you should use an AC source for your LED's, make sure to place sets of LED's in opposing direction.  The electrons in an AC source move back and forth (which saves energy, read up on Tesla), so you'll need allow current to move in both directions.  This actually works in your favor, because your will always have an LED lit.

    leds when used in the rectangular sine wave type ac in turn are brighter at a high voltage.