After the two boards with the resistors and connections was soldered to the LEDs (see post), now these two are sewn on both shoulders. The LEDs have a different cable length and were able to different shoulder, back and front areas. the two boards are wired to each other and need for the Arduino Uno only one PWM-pin and ground.
To scatter the light glow of the LEDs, we use fiber optic light cable and glue them on top of the LEDs. Then the length of the fiber optic cable has been adjusted on the costume.
To illustrate, here’s a video: