There are times when you don’t need much processing power for your project but you do need a lot of I/O pins. It often doesn ... the answer is to use a port expander chip.

The MCP23017, a 16-bit I2C GPIO expander, has always been a tasty chip. With 16 GPIOs addressable over I2C, proper push/pull outputs, software-enabled pull-ups, eight addresses, maskable ...