I2C expanders, or ADCs will give you plenty of pins for whatever project you have in mind. All these require extra components, though. Enter the ExtraCore library for Arduino, a software library ...

By using a protocol called Inter-Integrated Circuit (I2C), the Wire library greatly reduces the number of wires required to connect devices. The protocol is supported on all Arduino boards ...

Using an Arduino Pro Mini, a handful of buttons ... you to control the Si4735 from your microcontroller of choice over I2C. He’s currently tested it with several members of the official ...