Programmable Christmas Tree Lights by slumou

Last crawled date: 3 years, 3 months ago

Christmas tree lights based on an Arduino and addressable RGB LEDs with embedded WS2811s. This allows you to program virtually any pattern you can think of, and the LEDs can be replaced if any fail. Unlike traditional fairy lights, the failure of any single LED will not cause the others to get a higher voltage and fail as well - it may cause a break in the circuit but you will know exactly where it is and you can repair it.
2 pieces are 3D printed:
the box+lid for the controller
the individual LED holders+covers - one for each LED
Electronic parts needed:
some addressable LEDs (I used 40) https://www.pololu.com/product/2535
Arduino Uno
220 ohm resistor
390 ohm resistor
2.8k resistor
10k resistor
10 mF capacitor
some stripboard (or any other means of building a circuit) and connecting wire
3-core flexible AWG22 or similar cable (number of LEDs x distance between LEDs + lead from controller to first light)
any pushbutton
16x2 LCD screen (can leave this out if you do not want to see what pattern/mode is running)
5V USB charger
Some plugs and sockets (I used audio plugs/sockets I had lying around, and split my LEDs into 2 strings that are daisy chainable)
The circuit diagram is included. The LEDs are simply daisy chained (data in, power in for first LED; then each LED after has its data in connected to the data out of the previous one and power connected to previous one) - this is why you only need a 3-core cable.
The Arduino code I used allows for multiple patterns and a random or sequence mode.
For a power supply, I used a 5V USB quick-charger. It needs to push out enough amps for all your LEDs - 170mA for arduino + 50mA per LED at full brightness. I went with 3A to allow for a little expansion. To prevent the quick charger from increasing the voltage to higher than 5V, I had to connect the 2 data pins together - this is critical! If you opt to use a USB quick charger, make sure you test this before blowing up your arduino and/or LEDs.