Picture of A Charlieplexed Christmas Tree
Welcome to my first Instructable. I'd appreciate any constructive criticism you care to leave in the comments, but please be gentle.
Having recently built a 4x4x4 LED cube, I thought it might be interesting to apply the same techniques to building an LED Christmas tree. I used a single white LED as the 'star' and then a mix of red and green LEDs forming the sides. Initially I thought to make the tree star shaped in cross-section, but eventually realized that a six sided star would be easier as the supports could be made out of two identical triangles.
I used an Arduino to control the light patterns with a sketch loosely based on some sketches for a 3x3x3 LED cube.
What you are going to need:

1 medium white LED
15 diffused red LEDs
15 diffused green LEDs
6 resistors (values depend on the LEDs chosen, I used three 10 ohm and three 1k ohm)
some medium gauge copper wire
some fine gauge copper wire
an Arduino, I used a Freeduino
an Arduino compatable prototype shield
some male headers to attach the protoshield to the Arduino

Step 1: Building the frames

Picture of Building the frames
I decided to make the tree with five layers and a single white LED on top. This meant I needed to construct 5 six sided stars to support the different layers. I decided on a base 8 cm across which implied that the stars should decrease around 1.3 cm per layer. I then measured out an 8 cm equilateral triangle on a piece of hard wood and drove in three nails at the vertices. I then bent some medium gauge copper wire around the nails to form a triangle. I cut off the excess wire and soldered the two ends together.
I then built a second identical triangle. The two triangles were soldered together to form a six sided star.
Four more stars were made similarly by decreasing the distance between the nails by about 1.3 cm per layer. The smallest layer was pretty tiny and I might try decreasing the amount of change per layer next time.
alcurb7 months ago

Very nice effects in the video.

I can't find the schematics on your instructable. I have a visually-oriented learning style and I need to see a schematic to build one that I can scale up.

Thanks for posting.

cgrrty1 year ago
I like it
donce161 year ago
Very nice job :)
Geekaton1 year ago
what size LEDs have you guys used for this?
lmperkins (author)  Geekaton1 year ago
They were normal 5mm LEDs.
LeskoIam2 years ago
Hello again! Just to show off here is my christmas tree (just some pictures). Keep up the good work, man
lmperkins (author) 2 years ago
You are correct, see my comment in step 4 on choosing resistors. I usually find measuring the actual current flow in a system once it's built works better than simply using a calculated value as components vary a fair bit. The suggested resistors worked well for me, but YMMV.
LeskoIam2 years ago
Just one thing. I looked up the specs for original Arduino (2009) and just want to say that pins can safely sink or source 40 mA of current. So if you light up a column of LEDs (20mA per LED times 5 = 100 mA) is more than twice as much.... Just be careful and do the math and use transistors or driver IC. And correct me if I'm wrong. Otherwise, great project with a lot of educational content!
teeh3 years ago
Nice work! A will be good gift with a small barebones arduino clone. Congrats for the first non cube charlie.
nobusato933 years ago
What is the power rating of your LEDS? :)
lmperkins (author)  nobusato933 years ago
According to Sparkfun they are rated to 20 mA at 2.2 volts. This works out to 40 milliwatts.
sjswanner3 years ago
Great project. Just got done building and programming. This is the first project that I have done like this and programming it was fun.
lmperkins (author)  sjswanner3 years ago
That's great! If you have a picture to post, it would be fun to see how it turned out.
Slittape3 years ago
Nice workmanship! Very clever to use a 6 pointed star.
mikeasaurus3 years ago
This looks great!
thank u..it was very informative...:)
Very nicely done.
Kiteman3 years ago
Ohhh, pretty....

I have great respect for folk that build stuff like this - I never seem to have enough fingers, myself.