For the shape we used the laser cutter of http://www.by-wire.net/ (thx a lot!) and for the moment two kinds of perspex.
The principle is the back-light for amongst others a liquid crystal display.
Step 1: Needed
the 3mm led's
3 coin battery cell of 3V
The second kind of perspex is transparent like glass. In this case the light of the bright pointed led directed forwards has to be broken to other directions.
That is why in these transparent add-ons there are little round shapes and lines in the center line of the led beam.
The shapes are made with Illustrator and exported as a dxf file, which can be used for the laser cutter.
Some of the ai files can be found here: http://contrechoc.com/blogProjects/led_3mm.zip
Of course other types of perspex can easily be used, like colored perspex. Experiment!
With a bit of (super-)glue the add-on is attached more permanently to the led.
(Most of the led's function around 3V so the coin battery provided a nice source of energy without needing resistors.)
Step 4: The Whole Collection
Using colored led's seems to be cool,
using colored perspex....
and than using it in clothing...
many things to explore!