Controlling Multiple LEDs

Multiple LED Control Using Minimum I/O pins



A truth table for controlling six LEDs using three I/O is shown below:

H = Output Set high (5V)

L = Output set low (ground)

I = Input

More LEDs can be controlled by using this equation:

Numbers of LEDs = (Numbers of PINs) x ( Numbers of PINs – 1)

For example:

Number of LEDs = 4 x (4-1)

                        = 4 x 3

                        = 12 LEDs