Hello,
I tried the RGB Led included in the Arduino Starter Kit, it's perfect and very simple to select the desired color. So I bought others which I thought was the same kind but they are "addressable". What does it mean?
I tried them as I did with the first one, but I only have the blue color in different intensity (in the 3 anodes). Any idea?
The addressable RGB LEDs typically mean you send it 3 bytes of data, each byte sets the PWM level for an LED from 0 to 255.
If they are WS2812B, then Adafruit.com has a Neopixel library to interface to it, a single data line is used that contains clock/data info.
If they are something else, a different library is used. Some use both clock & data so that SPI.transfer() or shiftOut() commands can be used. SPI.transfer will be the quickest, with up to 8 MHz clock speed.
Ah ok, it's more complicate for the same result finaly! Yes, they say they are WS12812.
So, I just need to connect my Arduino to that led and use the Adafruit_Neopixel library?
So, I just need to connect my Arduino to that led and use the Adafruit_Neopixel library?
Yes
it's more complicate for the same result finaly!
But if you want a string of 400 LEDs then these do it just as easily as lighting one. Try that with with your original type of LED.
I understand better, it's for many LEDs, not just one like I need 
Thanks for your help!