YOU WILL NEED THIS BOARD

The RTC Pi is a battery-backed real-time clock module for the Raspberry Pi and other compatible single-board computers. It keeps track of the time while the Raspberry Pi is switched off and allows it to retrieve the current date and time from the RTC Pi when it is switched back on.
This knowledge base section contains articles and tutorials on the RTC Pi, showing how to use the development board.
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.