Of course, to make things light up really cool, you need some kind of microprocessor. I have always used a bicycle safety LED flasher from my dollar store as the core unit of several ibles because It was an inexpensive self contained unit that had everything I needed, battery case, on/off/pattern switch, 5 LEDs and could cycle through different lighting sequences. You can make everything from light up hoodies, signal gloves, stoplight scarfs and logo scarfs.But then you feel the restraints imposed by the limits of the bicycle flasher. I finally got an arduino a few months back and started to experiment with it. Using it with an accelerometer allowed me to create a set of necomimi arduino cat ears.
Well, they are all examples of wearables but another part of the puzzle was missing. I had always used wire, regular insulated wire, as the circuit path for the circuits. Conductive thread is what makes it a true wearable. I finally have a few bobbins to experiment with. Conductive thread is fine metal fibers twisted into a soft thread or yarn. It is truly flexible but needs to be insulated when crossing wires.
But then you will find, jumping into the world of arduino is not really cheap. Costs add up with additional components. I only have an Arduino Uno. Now what to do when all the wearables are done with a Lilypad. No one can get their hands on a Adafruit's FLORA yet.
Here is my solution to using your ordinary Arduino as the microprocessor unit on your wearables. An easy mounting "shield" and a bus adapter to get the pinouts from the headers on your Arduino to your fabric...sort of a digital to real-world analog interface. I think it is hard to prototype when all of your input wires to the arduino are hard sewn to the "header". When you troubleshoot or prototype, you have wires that you need to disconnect or rearrange. This wearable shield also takes your prototyping directly to the finished product. The core arduino can be removed easily for use with other projects. Also, remove the arduino if you need to wash the garment. Hmmm, dry clean copper wires only?