I am looking to use a 5050 RGB LED strip to show either green, blue, and red depending on the battery I want two monitors voltage. If I take my LED strip and connect 12 volts to it and then ground one of the RGB pads the corresponding color lights up. I need to make a circuit or use an Arduino or Raspberry Pi to monitor the battery's voltage and send 12 volts to the corresponding pad to show green, blue, or red depending on the voltage coming from the battery. This is assuming that I have the right idea. If this will not work the way I am thinking or there is a easier way of doing this I am open to suggestions.
The battery I'm trying to monitor is a 12v 3s 6p 18650 pack. I can power the circuit from a different Source if needed. The LED strip is only going to be maybe 2 1/2ft long.
If someone could please explain how I can achieve or point me in the right direction I would greatly appreciate it.