YOU WILL NEED THIS BOARD

The IO Pi Plus is a 32-channel GPIO development board for the Raspberry Pi and other compatible single-board computers. The board is based around two MCP23017 16-bit I/O expanders from Microchip Technology Inc, allowing you to connect up to 32 digital channels to the Raspberry Pi.
This knowledge base section contains articles and tutorials on the IO Pi Plus, showing how to use the development board with various input devices.
Also useful for your Raspberry Pi project
Temperature & Sensing
1 Wire Pi Plus
Connect dozens of 1-Wire sensors - temperature, iButtons, EEPROMs - via a single GPIO pin. Stacks directly on the 40-pin header.
Analogue I/O
ADC Pi
Read up to 8 analogue inputs - perfect for pairing with your temperature sensors or other analogue-output devices.
All-in-one
Expander Pi
Combines ADC, DAC, 32 GPIO ports and a real-time clock on one board. The most versatile board for complex Raspberry Pi projects.