USB Powered LED Christmas Tree




About: I'm a just a not-so-average human with a passion for making. I see a world of hackers, makers, and producers as the sun rises in the near future. I'm starting olopede, an educational electronics kits com...

For the holidays, I wanted to give a couple of my friends something cool, by that time I had taught myself simple circuit theory and was infatuated with LEDs.

SO, I ordered the LEDs two weeks from Christmas, thinking this would be ample time for shipping and production. (I bought 200 LEDs for a cheap $12 on e-bay from sureelectronics) Unfortunately, it takes two weeks to ship from Hong Kong, and I got the LEDs on Christmas day. Now it's a bit late, as Christmas was about 5 days ago, but they are nice little presents for the future. And plus, I still might give them to a few people this year ;-)

This is my first Instructable and I hope you like it.

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Step 1: Gather Materials

You'll need:
Thick Copper Wire
19 LEDs (you can use multiple colors, I used green, blue, red, and white)
Red: 2.7 v @ 13mA
Green: 3.2 v @ 10 mA
Blue: 3.2 v @ 10 mA
White: 3.2v @ 10 mA
390 ohm X 4
330 ohm X 2
aluminum sheet
green wire
USB cable
wood (preferably circular, 1 inch diameter)
two peanut butter jar caps
cotton balls (optional)
shiny cloth (preferable)
hot glue

Soldering Iron
Tin Snips
Propane Torch
Diagonal cutters
wire stripper (if you want, I use teeth)
dremel tool
Chop saw
drill bits

Step 2: 1st Step

To straighten the copper wire, just clamp it in between two large pieces of wood, then rotate the wire until it's decently straight.

Then, with the wire in the clamp, use the propane torch to heat up the wire, then put a band of solder about two inches from the bottom of the wire. (I only took a picture the second time I did it, so the heat shield is already there)

Once you do this, bend one of your base colored LEDs' cathode about 3mm from the end and tin it. Now, you should be able to hold the LED so that the bent stub lines up with the wire, and quickly melt both the solder on the lead and some of the solder on the wire. Note: you will not be able to melt all the solder on the wire, because the copper wire draws the heat away from it.

Step 3: Making 1st Ring

so, you have your first LED on, now I'd stick to that color led (green for me), and put another 7 on the bottom row. (total = 8) Also, don't forget to bend the Anode left or right, it doesn't matter which, but you'll have to stick to that direction for the rest of the ring

so, prepare the led EXACTLY the same way you did the other, bending the cathode the same amount, tinning it, and soldering it to the wire. REMEMBER: BEND THE ANODE IN THE SAME DIRECTION

repeat this until you have a ring of 8 (green) LEDs

Then evenly space out all the LEDs in the ring, the anodes WILL overlap- this is a good thing
Tin all of the anodes on top, going around in a circle, then solder them to the anodes below them.
-I just did it this way, feel free to just solder it at first

Then, trim off all excess leads - you don't need no stinkin' excess leads

Step 4: Making 2nd Ring

Now, you're going to have to put on another ring of solder, about 3/4" away from the first ring, but the LEDs are there and you don't want them do melt, do you?!

Make your aluminum heat shield using some aluminum, tin snips, and 300 mana points
cut a square, circle, or any euclidean geometric shape large enough to protect the LEDs and cut out a slit into the center of it with the snips.

slip the shield on the wire just after the first ring and bring out the torch!

Make another ring of solder on the wire, and prepare your LEDs. BUT:
This time, you are using 6 LEDs, I alternated colors, using your base color and some other
one (I used green and blue). Also, you must make the cathodes shorter this time, so bend
the cathodes a decent amount in, maybe half way or 1.5 cm closer to the head.
NOTE: make sure you check the voltage and differences between the two different colored LEDs
This is important because if there is a large difference, then you will have to run a separate wire for that colored LED, and just put those LEDs in parallel with themselves and not the other LEDs

Step 5: 4th and 5th Ring

This time you will again alternate some color with the base color (I did red & green)
For the 4th ring you only use 4 LEDs, and make the leads really short, maybe 1 .5 cm total in length
Okay, you know the drill: heat shield -> PROPANE -> solder -> prepare LEDs -> solder LEDs ->solder anodes together
NOTE: you may be saying "But you said the red voltage was 2.7 and the green was 3.2, what did you do?!"

well, I soldered the two green LED in parallel and the two red LEDs in parallel, later I will run a wire just for the reds and the greens will be attached to the rest of the tree like normal


This one isn't really a ring.
Using tin snippities and MANLY MAN POWER, cut the wire about 1/4 in from the 4th ring, then tin the cathode, and solder it to the 4th ring's cathodes/ the solder ring down there. you can adjust the height of the 5th "ring" to whatever you want. I kept the height change constant. I suggest wrapping the anode in a circle around the cathode, this way all the green wires will be easy to solder to the top. I also used a white led, for super-coolness points!

Step 6: Wiring the Tree

Okay, so the tree is built, and now all you need to do it hook it up to the USB cable, and plug this sucker in.

First, you're going to need to get all of the green and blue LEDs in parallel. As of now, there are 8 greens in parallel (bottom ring), 3 greens and 3 blues in parallel (2nd ring), and 2 greens in parallel (3rd ring). In order to get them all into parallel, you will need to jump some wires from the anodes of each ring to the anode of the next. Note: you may want to make these connections look like a Christmas tree, as the curves normally found in drawings of Christmas trees, this is quite simple to do.

Now, you can also add more of these connections to make more of the "Christmas curves" around the tree. The light from the LEDs should color them in later, if you don't have any green wire laying around. (I used Hard Drive cable)

Next, hook a wire up to the red LEDs' anode, and snake it down to the bottom of the tree. This wire will have its own resistor.

Finally, hook up the White LED's wire, and like the previous step, snake it down to to bottom. This wire will also get it's own resistor.

Step 7: USB TIME!

Take the male USB cable and strip the end of it, you should see red and black wires, and two other colored wires. Cut off the two other colored wires, these are for data transfer and we only need the POWER!

The USB will supply 5V @ 100 mA, so if you aren't using the same LEDs as I am, you can calculate the resistor values needed with OHM's Law

Now, we will have to make our resistors.... using other resistors!
In order to get the correct value with what I had lying around the house, I had to put two resistors in parallel.
If you are using different LEDs than I am, and need different values, use this formula:
R3 = (R1*R2)/(R1+R2) I wanted two 178 ohm resistors and one 200 ohm resistor
(I know that 390/2 = 195, but it's close enough)
Now, put one of the 390s in parallel with one of the 330's and make two of these R3's
Next, put two 390's in parallel with each other to make the 195 ohm resistor

Take the three calculated resistors (178, 178, and 195 ohm) and solder all the leads on one side together, so that the other side can be attached to 3, separate wires. Make the resistor "pack" as small as possible. (look at the photo, it's easier to understand)
Clip off all excess leads on the side that you soldered em' all together.

Now, with the cable stripped and the + and - wires stripped as well, tin the wires and attach the red wire (+) to the resistor "pack" on the end where all three resistors are connected.
Also, extend the black wire a bit, we need it a couple inches longer

Now you are ready to make the base!

Step 8: Base Tree

Take the wooden block (or circular shape) and drill a hole in the center of it with a bit that is a tad bit larger than the diameter of the wire/coat hanger you used. Now, cut the block in half with a chop saw.

now, using a dremel and the cutting tool, cut off the top part of one of the peanut butter jar covers.

Heat up your hot glue and glue one of the wood pieces to the peanut butter top piece so that the hole lines up in the exact center of the cap (there's a little nipple so it's easy to do). Next glue the other piece onto the still-intact peanut butter jar lid. Then take the same drill bit you used for the wood and drill into the intact peanut butter cap through the hole you made in the wood.
Now, in the mostly intact lid, using a file (or dremel), make a 1/4 in by 1/4 cut into the side of the lid, this is for the USB cable.
Next, pull the three wires (one from the green/blue LEDs, one from the red LEDs, and one from the white LEDs) through the hole, and then put the tree trunk through the hole as well. It should fit pretty snugly.

Now, solder the wire from the green/blue LEDs to one of the 178 ohm resistors( one 390 and one 330) , the wire from the red LEDs to the 195 (two 390's) ohm resistor, and the wire from the white LED to the other 178 ohm resistor ( one 390 and one 330). Cover all the open connections (except the open end of the black wire) with electrical tape, you don't want a short, and hot glue the USB cable into place giving it about an inch inside the lid.

Now, you can try and solder the extended black wire to the tree trunk, but I suggest just stripping it pretty long and contact fitting the wire between the trunk and the bottom wooden piece. (the trunk goes in the hole, but first take the stripped wire and put it across the hole)
Next, hot glue the tree trunk into the bottom wooden piece, and test the usb cable/tree. Everything should light up and you should be very happy.

Now, close up the two lids and hot glue them together, MAKE SURE that the tree is perpendicular to the top lid, we're not making the leaning tower of treeza.

NOTE: The one thing I regret is not making the base heavy enough, you can weigh it down with some bolts, washers, what ever. Just make sure you insulate it so that you do not short out any of the circuitry.


Finally, we're almost done!

there are tree (rofl) options here:
1: Take some of the cotton balls and "fluff" em' up to make fake snow. then hot glue your fake snow to the wooden base of the tree. Try and cover up as much of the lids as possible, make it look nice.

2: Use shiny cloth to make your tree shine! Hot glue around the base and attach a 9.5 X 3" strip of shiny cloth. use ultimate folding techniques to make the strip meet up nicely in the center. (You can combine more than one option)

3: USE YOUR IMAGINATION! Make it UUber cool and mod it with more LEDs, or whatever you want.

Also, if you don't mind tedious soldering and wire cutting/ stripping, you can continue to make those little curves previously mentioned in step 6 all the way around the tree. this will make it look pretty darn cool, but WILL take a while. MAKE SURE that you don't wire any of the anodes to the grounded copper wire, and also that you don't wire the green/blues to the reds or whites, or the whites to the reds. (I didn't do this, I'm too impatient)


Plug it in and enjoy your holiday-spirited tree!

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    68 Discussions


    9 years ago on Step 9

    nice looking... just when you connect it to a pc does anything happen on the pc screen?


    9 years ago on Introduction

    Hey. Nice i love this somes pics, I created yesterday.. nice instructions  GREAT!! sorry about my english ....


    9 years ago on Step 7

    why do you need a separate resistor for the white LED if its the same voltage as the blue and green?

    1 reply

    Reply 9 years ago on Step 7

    So each color LED draws different amount of current at different voltage levels.  If you were to try putting a while LED in parallel with a green LED, the white LED wouldn't ever 'clamp', or turn on - even though the specs say that both of them operate at ~3.5 volts.  This is just due to the material properties of the elements that the diode is composed of to produce that color light.

    Hope that helps, and sorry for posting so late.


    9 years ago on Introduction

    It's a good idea and i was looking for something to make for friends. But I found useful how u wire the USB cable. So I decided to make a ball out of leds soo i can use it even when its not xmas time :) thx dude cool instructable

    2 replies

    Reply 9 years ago on Introduction

    please post pics, i want to see how it turned out. it sounds really interesting!


    Reply 9 years ago on Introduction

    Zack i will as soon as i make it... workin on it its bit tough rly... ill maybe make some instructable for it dunno yet


    Reply 9 years ago on Introduction

    me too lol. it didn't burn my foot, but my new pair of shoes now look real funny with the burn spot on them


    9 years ago on Introduction

    Thanks for the inspiration.
    I put together this, it's not as tidy as yours, but it's powered from 2 AA batteries.

    1 reply

    Reply 9 years ago on Introduction

    WHOA!  Awesome work!

    Perhaps you have the right idea -> Not using a particularly thick piece of metal for the 'trunk.'  I sort of like the tilted rings, too.  It's got a 'firework tree' sort of feel to it.


    9 years ago on Introduction

    This is a nice instructable, but if i could make a suggestion. Please learn how to use your digitial camera, or build a light box to put your pics subjects in. Your pics are really not all that helpful in determining the position of the electronics. Drawn pics would have been a lot better for the quality.

    1 reply

    Yeah, sorry about that.  I learned how to use my camera after I posted my first (see the rest of my i'bles).  I want to re-take the pictures, eventually. 


    Reply 11 years ago on Introduction

    Most LEDs require only 3V to "clamp" or attain full brightness, so 5V is plenty. I used a resistor to drop 5V down to 3V, and from there it really just depends on the current. I gave each LED at least 10mA, which is what my spec sheets said my LEDs needed to clamp. Anyhow, if you're having trouble with your LEDs - let me know!

    If you wanted to be really pedantic you could have used a complex regulator so that the current went up as voltage went down, unless resistors do this already (correct me if im wrong, but dont they use up extra energy as heat?)



    Reply 9 years ago on Introduction

    usb ports have between 500mA and 1.5mA at least mine do lol and my leds need 20mA to clamp so its more than enough


    11 years ago on Introduction

    i am trying using chrismas lights instead and i can get from 8 to 12 lights working depending on the color. after that i get a box on my computer that says there is a SURGE IN THE PORT HUB. i thought that lights only take the power that you give them so you would think they would just dim down right?