Quantity   Component name
1 × Arduino Uno R3 Used a compatible board with 16u2 usb uC
4 × MCP23S08 | MCP23008 Used instead of '595 and '165 shift regs to allow either SPI or I2C connectivity
4 × CD4067 Used in multiplexer shield
1 × RepRapDiscount LCD breakout Used to allow basic UI menu, plus SD memory and a buzzer. Power hungry, might have to make changes in future.