Connecting an Arduino to a 7 segment display – part 2: reducing microcontroller pins

connecting an arduino to a seven segment display

In my previous post, I showed how to connect seven segment displays to your Arduino microcontroller and how to drive them through multiplexing to display numerical values from your program.
In this post, I will build on that circuit and reduce the number of pins used on your microcontroller, as promised.
The circuit so far had 12 microcontroller pins used up to drive the seven segments (and decimal point) and select each individual digit display. What if you can reduce the number of pins to just 3? Easy! We can do this using shift registers.

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