I would want to do something like a police siren with 12 RGB leds. As I want to control them individually I need 36 pins and I think that there´s a lot (i would need arduino mega and it consumes a lot of battery)
could you recommend me something???? And... I have seen that using random pins for my RGB led it does not work equally; could you tell me why????
Please read the forum guide in the sticky post, then modify your post above so that we have some chance of helping you.
You can consider an addressable LED strip. That will only cost you one pin.
You can also consider multiplexing (there is a section on the forum for that).
Regarding power consumption, the two determining factors are how many leds are ON at a time and how bright you want them to be.
And... I have seen that using random pins for my RGB led it does not work equally; could you tell me why????
Please explain in detail.