Multiplexing Seven Segment Displays

Video explaining what multiplexing is, why we do it and how it is done.  Covers using the Arduino to handle the multiplexing and using a 7219.  Using the 7219 we can control up to 8 seven segment displays while using only 3 pins from the Arduino.  The 7219 also handles all refreshing of the display and requires no additional drivers on the common signal of each seven segment display.