After this tedious step, he designed a PCB that hosts an Arduino Nano to accept input, two MCP23017 GPIO expanders to give it enough outputs, and CD4066BE CMOS switches to trigger the connections.

Create a new folder called "LiquidCrystal_I2C" under the folder named "libraries" in your Arduino sketchbook folder. Create the folder "libraries" in case it does not exist yet. Place all the files in ...