If you fancy making your own smart clothing, then Kitronik's new Igloo project is something you should check out.
Kitronik's system is based on a programmable miniature control board (pictured above) which is sewn into a piece of clothing and then by using conductive thread it can be hooked up to other boards also tucked away in the garment.
Don't expect to be able to wire up a shirt which can detect your heart rate, though, as the tech involved is more basic here – it's designed to be cheap (the main board itself only costs just over a fiver including VAT if you buy in batches of 10) and usable by schoolchildren exploring the world of wearables as well as keen consumers who want to experiment with the technology.
Aside from the main control board, the other boards available include different coloured LEDs, simple buttons (which can be used to switch on said LEDs), buzzers, and various sensors such as for example a light sensor which can trigger functions based on whether it's light or dark.
There's also a sewable coincell battery board, of course, to power these little pieces of electronics (or you can use AAA batteries for more longevity, although obviously these will be far bulkier when being attached to a shirt or similar).
On the software side, the PICAXE Programming Editor offers a simple flowchart style method of programming your kit, ensuring that this system is accessible even to complete computing novices (or you can program in BASIC if you prefer).
It's certainly an interesting project and before long we will probably see wearable kits which offer more advanced functionality to create your own custom smart clothing with.