Thank your for your quick replies, I appreciate.
In the meantime I’ve found batteries (originally from fishing) with LEDs which fit into the inner space of arrows for sure.
The idea now is, to replace the colored LEDs with pure white LEDs and additionally use golf finder goggles (which filter out all colors except white). I’d imagine, the white LED would boost the effect of those goggles. At least this is a quite cheap way for the first try!
And if this try fails, I’ll come back to I0TA probably, since the battery could used for active RFID technology probably very easy.
Thank you all!