It was already long time ago, I finished base coat paint. Before I start painting, I have to finish electrical work.
First, I attached the optical fiber. If I attached the fiber before I did base coat, there is some risks to break the fiber, so I decided that I attach them after finish base coat.
Also, I soldered all wires, connetting all LED, Arduino and AtTiny85.
I needed to solder the wires at very tight space. It was a very nervous job, because I could not touch irons to fiber or basecoat at all.
After attach all optic fiber, LED and Arduino, connect battery and checked whether all the LEDs are lit.
It seems that it works well.
Next, start painting, finally.