Computer Controlled Christmas Lights

It’s that time of the year again, and the halls are being decked with trees, the trees covered in lights.  You know holiday season is getting close when the Christmas light projects start rolling in! Christmas is almost here so it’s time to kill a tree, set it up in your living room, and put a few hundred watts of lights on it. It is dark outside, so it would be a good idea to cover some trees or your house with some lights. When you have lots of lights, it would be nice If I you could control then with computer… So here are some links to interesting Christmas lights related projects:

How to find broken bulb in light string? It is hard. Having one light fail becomes a major hassle especially after they are installed on the roof of the house or on a fully dressed Christmas tree.  Simple tester checks Christmas-tree lights article gives one simple idea how to test main powered light string. This simple gadget is really simple and works great, but it exposes the user to potentially lethal line voltages. Bad-bulb finder fixes Christmas lights article gives plans for modernized safe to use LED version of that one. Santa’s elves fix Christmas lights faster but now demand higher pay article tells how “Light-Keeper–Pro” to tester helps fixing the Christmas lights easier (and gives idea how that device works).  It also tells how how some light vendors have eliminated the extreme frustration of an entire string’s going dark, leaving you to frantically search for that one bulb that’s the culprit.

How modern multi-color LED light strings work? It is pretty easy to do the PWM controlling for RGB LED string where all LEDs have the same color (you just need Arduino for PWM controlling and some FETs). But how those strings where each LED can be controlled individually are built? The answer are special LED modules that have built-in control IC in then, and they can be controlled with one wire bus. WS2812 addressable LEDs have been seen in many Hackaday LED light projects  (for example Cypress PSOC 4 + ESP8266 WS2812 RGB XMAS Lights). Another IC for that is APA102.

The Epoch Christmas Tree article tells that Dan has a tree and a bunch of programmable LEDs, but merely pumping jollity down that strip of LEDs wouldn’t be enough. The Nerd Quotient must be raised even higher with a tree that displays a Unix timestamp.

Deck the Halls with a Raspberry Pi Controlled Christmas Tree page shows a Christmas Tree light show controlled by a Raspberry Pi. Yes, it could have been done it with an Arduino, or a 555 timer IC, but the Raspberry Pi makes for a convenient platform. With a WiFi module, code changes can be made remotely and the Raspberry Pi’s built-in audio interface also makes it easy to sync music to flashing lights.

Google Gets Thousands Of Girls To Program The White House Christmas Tree Lights article tells that the 92nd annual White House Christmas tree lighting ceremony is getting a tech twist this year. Over 300,000 people, mostly young girls, participated in Google’s Made with Code campaign to program the way the lights will dance on the 56 official White House Christmas trees during this evening’s lighting ceremony. Aach girls’ code has a very specific time, down to the “exact second.

In  German house displays over 400,000 Christmas lights – video a homeowner explains the process of decorating his house in Calle, Germany, with more than 400,000 Christmas lights he has acquired since 1999. Rolf Vogt says his home has become somewhat of a local attraction.

Christmas Lights And Ships In A Bottle article tells about wireless Christmas lights idea. AURA: The first ever, wirelessly powered Christmas lights Kickstarter campaign is selling wireless Christmas lights, controllable with a smartphone. If it works and passes all the certifications (especially EMC), it looks like a brilliant idea.

Here are links to some interesting Christmas Lights display videos:

Best Christmas Lights Show 2011 – The end is awesome!

Sandstorm Christmas Lights Techno

Sandstorm – 2010 – Lights For Riley Christmas Lights

2010 Light-O-Rama SANDSTORM in HD

Behind the scenes videos:

Setting Up a Holiday Light Show

Christmas Display Behind the Scenes

2011 Heather Lake Christmas Light Show – Behind the scenes

Introduction to Light-O-Rama, (the holiday light show software) part 1 

Then some over-the-top idea from few years back: Oh sweet Jesus, what is this? Tesla Tree, Tesla Tree: Merry Christmas from the Eye of Sauron web page shows that some guy in Australia has been making Christmas trees out of Tesla coils: the tree shape will be outlined by sparks from a rotating rod on top of the Tesla coil.

For more ideas check my previous Christmas light related postings.



  1. Tomi Engdahl says:

    Related article link:

    Arduino LED controller shield makes complex RGB LED lighting apps a snap

    The Arduino-compatible lighting RGB LED lighting shield reviewed here was designed to give designers a low-cost easy-to-use open-source platform for fast prototyping and inexpensive evaluation of multiple LED light engines. It is based on a XMC1202 MCU which integrates an ARM Cortex-M0 processor and a dedicated Brightness & Color Control Unit (BCCU) core. The BCCU contains 3 independent dimming engines with 9 independent Pulse Density Modulated (PDM) channels. Due to space limitations on the PCB, the shield only provides access to 1 dimming engine and 6 channels. The shield includes an I2C bus which the MCU uses to communicate with a host controller. The shield’s reference firmware supports 10 basic sets of commands which can be used alone or in combination to produce a wide range of lighting effects.

  2. Tomi Engdahl says:

    Glowing Xmas Snowflake Sculpture
    Used NeoPixel LED strips to build an interactive Christmas Display for an office

    I chose Adafruit NeoPixels as the filler because they are individually addressable and easy to use (see edges of sculpture in sidebar photos). 70 meters of Neopixels in 28 addressable strips are controlled from an Arduino Mega/Due combo (see photo in sidebar). The controller talks over RS-485 to the Sensacells, using their API to request sensor states. A big lookup table associates NeoPixels with neighbouring sensors. The colors (both idle & triggered state) are set by external dials.

    To get this working was more complicated than I expected, especially in terms of communication and power distribution.

  3. Tomi Engdahl says:

    Use Ruby to Make Any Window A Blinken Window

    [Akhil Stanislavose] wanted to spice up his window decorations for the holidays. Inspired by blinkenlights, he decided to make his front window interactive. The Blinken Window is a grid of 6 x 10 programmable LEDs running on a Raspberry Pi. Since a RasPi doesn’t have enough GPIO pins for 60 LEDs, [Akhil] built an expander board using 8 daisy chained standard 74HC595 shift registers to accommodate them.

    [Akhil] demonstrates how you can use the Blinken Window to play a version of Pong using your smartphone as the controller. [Akhil] has also provided a few basic animation examples that can be expanded upon. We’d enjoy seeing an implementation of Tetris.

  4. Tomi Engdahl says:

    MacBook Air survives 1000-foot, 125mph fall from plane

    A South African pilot appears to have taken the name of his MacBook Air a little too literally, managing to drop it from the light aircraft he was flying when the canopy flew open. The MacBook, along with his flying license and logbook, fell 1000 feet into the fields below–but amazingly survived the experience.

    the unibody casing was bent, the glass trackpad shattered and the cooling fans were damaged, but the screen remained intact and the MacBook continues to work …


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