Carrera / Slot Car Startampel / Starting lights

Staring lights for the carrera slot car track of a friend. I had this lights in my stuff box for ages: https://www.pollin.de/p/led-matrix-opto-14431eg-rot-gruen-4x4-120748 and this was a nice reason to use it.
It uses a DigiSpark ATTiny 85 clone for control and features a beeper to indicate status.
If I have some more spare time I can extend the description of the electrical circuit.

Edit: I also uploaded the Arduino Sketch which is real basic and badly coded but I one can understand it :-)