Animated LED Fire Necktie

Updated 2014/3/22

The Hunger Games costumes are catching fire, so how about an animated LED fire simulation necktie. With this electronic wearable you can be virtually warm in winter.

I  built the display using an 8x8 color LED matrix from and an Arduino Pro Mini 5V/16MHz  controller from 

Gilad Dayagi (giladaya) wrote the original software and described his animation work and algorithm in the Arduino forum: 

I modified his code to use the Adafruit NeoPixel  8x8 display and placed the updated code in at:

The Adafruit LED matrix display, Arduino controller, and battery holder fit nicely in a 3 inch wide necktie. The parts do not add much weight to the tie when using coin cell batteries. Placing the LED matrix behind the lining in the tie helped to diffuse its light.

Parts List:

(1) Adafruit NeoPixel NeoMatrix 8x8 64 RGB LED Pixel Matrix (
(1) Arduino Pro Mini 328 - 5V/16MHz controller  (
(1) 2 x 2032 Coin Cell Battery Holder 6v output with on/off switch and connector JST (
(2) CR2032 Lithium Coin Cell Battery
Velcro Strips
Stranded wire ( I cut up a network CAT5 flexible cable and used the internal wires )

An alternate power source that lasts much longer is a 3 x AAA battery Holder with on/off switch and 2-pin JST. This power source weighs down the tie noticeably and is more bulky.

I soldered all the wire connections. The circuit is very simple. Here is a diagram of my layout and circuit:

Note that header pins were soldered on the Arduino controller to program it.

If you don't want to use headers you can use the sparkfun pro micro and program with a USB connection. I used the Arduino 1.0.5 SDK and installed the Neopixel library from
Adafruit has very nice tutorials about Neopixel programming. Highly recommended reading for this project if you want to build one yourself.

I have an Adafruit Flora that I could have used as a controller, but I wanted a smaller board to be able to fit everything behind the 8x8 display board. If you are new to Arduino projects, I recommend the Flora.