I’ve recently made this necklace with LEDs and glass beads, and it is controlled with a small micro controller and accelerometer.
I used the Anio Magic kit for motion sensing using the Chiclet. It was fairly easy to use and to put together with two slight issues. One was the inputs (particularly on the accelerometer) were not clearly labeled (+ and -) and the conductive thread seemed to break and ripped was easily.
The battery, pre-programmed micro controller, and accelerometer were all sewn to one side of a piece of neoprene. This was then covered with a cotton fabric and the LEDs were then sewn to this.
The glass beads were then also added to the fabric and then the piece was attached to the necklace.