Again shift registers can come to the rescue. There are other times when you have a lot of sensors, displays or other I/O devices and can’t spare a lot of pins for LEDs or switches, but you need a multi-LED display or a small keypad. The shift register will allow you to address a large number of LEDs using only a few Arduino I/O pins. There are many ways to solve these issues, including running the LEDs ina matrix or using a shift register.

non-addressable) RGB LEDs would put you past the limit. If you wanted to expand to a 5x5x5 cube then you’re out of luck, you’ll need 125 LEDs for that and you can’t control them individually with one Arduino.Įven a 4x4x4 cube using standard (i.e. A cube with a 4x4x4 dimension would require 64 LEDs, within the capability of an Arduino Mega 2560 if you “borrow” a few analog pins. So with 70 potential I/O pins you don’t usually have a need for more. Expand your ArduinoĪrduino’s have a number of digital I/O ports already, in fact, the Arduino Mega 250 boasts 54 digital I/O pins plus another 16 analog inputs that can double as digital I/O pins.

These handy devices are used for all sorts of purposes like data conversion, buffering and storage, but today we will be seeing how they can also be used to expand the number of digital I/O ports on an Arduino or other microcontrollers.īy learning to use shift registers you’ll be adding another handy tool to your designers’ toolkit. Today we will work with a couple of basic electronics “building blocks”, shift registers.

Serial shift register