For these LED bracelets we used the following: felt fabric in different colors (from amazon.fr), LED lights (from amazon.fr), conductive thread (from Kitronik), 3V Coin cell battery holder with the latch (from Kitronik), 1 x CR2032 Coin Cell Battery and velcro strap and/or snap buttons.
To start with, cut a rectangular shape from felt fabric. Make sure that it is long enough for the wrist of the bracelet holder. Then cut another slightly slimmer piece of the same length for color effect. Design your circuit: how many and which color of LEDs you’d like to have. Sew your circuit.
The basic E-Textile LED circuit is very simple. It is created by placing the LEDs in parallel with the battery holder. You need to attach the + sides from the battery holder with the + side (longer leg) of the LED and the – sides from the battery holder with the shorter leg of the LED. We’ve used a battery holder with the latch in these projects for easier switching on/off.
After your circuit is functional, cut some shapes from a colorful felt of your choice. Cut a small hole in the middle of them and slide them through the LEDs. If they slide out, attach them with few stitches.
Lastly, to fasten the bracelet, attach a piece of velcro strap or snap buttons for each end of the bracelet.
See this excellent Blog post on How to Make Basic E-Textile LED Circuit from Kitronik for additional information on circuits and LEDs.