Duty Cycles with 555 Timer

In combination with capacitors of different sizes and variable resistors/sensor inputs, 555 timers can be used to cycle through repetitive outputs, such as blinking lights or an RGB led shifting through vales from 0 to 255 and back without programming through a purely analog circuit. Using resources such as House Of Jeff, it becomes easy to calculate the resistance needed to acquire the desired frequency (sound based and time based) of chosen outputs.