This project uses an Arduino Duo R3 and 3 push buttons to control a RGB LED.
The 1st button selects which color of the RGB LED you want to adjust. The other 2 buttons allow you to adjust the brightness of that color either up or down.
There are 3 green LEDs the indicate which color of the RGB LED will be adjusted and a 4th green LED that indicates the individual brightness of that color component.
A beeper is also used to provide audio feedback that the button is being pressed (ticks) and if you have reached the minimum or maximum value (chirps).