Assume that you are moving towards a complex microcontroller project bundled with blinkers, beepers, and a display panel. To link a standard 16×2 LCD directly with the microcontroller, for instance ...
A while ago I received a couple of I/O port expander modules that use the I 2 C protocol. Using that Chinese module, you can use only the SDA and SCL pins of your Arduino, or any microcontroller ...