Adafruit DS1307 Real Time Clock Assembled Breakout Board

Description

This
is a great battery-backed real time clock (RTC) that allows your
microcontroller project to keep track of time even if it is
reprogrammed, or if the power is lost. Perfect for datalogging,
clock-building, time stamping, timers and alarms, etc. The DS1307 is the most popular RTC - but it requires 5V power to work (although we've used it with 5V power and 3.3V logic successfully)

Works great with an Arduino using our RTC library or with a Raspberry Pi (or similar single board linux computer)

• PCB & header are included
• Plugs into any breadboard, or you can use wires
• Two mounting holes
• Will keep time for 5 years or more

Note: This product does not come with a CR1220 coin cell battery.

The DS1307 is simple and inexpensive but not a high precision device. It may lose or gain up to 2 seconds a day.