I’m trying to build a Lego Technic panel with some RGB LEDs (do you know they fit perfectly in Technic’s holes?) driven by an Arduino.
Anyway, my question is: how do I connect multiple (say, 9) RGB LEDs to be driven simultaneously? I want to use RGB LEDs because, although they all have to show the same color, this color may vary. There are tons of info about how to drive them independently but I’d like to light them up all the same, like they are a single one.
I know I have to use an external power supply, probably transistors activated by Arduino to power the LEDs and resistors but I have no idea about the whole circuit, what goes where. I don't have a power source yet but best thing would be to use USB from PC, if it would suffice.
LEDs need to be driven from an Arduino UNO which decides what color and luminosity to display; this is going to be some kind of semaphore on my desk.
I know the question is a bit broad but worth a shot. Any help would be really appreciated.