DS1307 Real Time Clock Module Board

This little, RTC (real time clock), will keep track of time even if reprogrammed or if power is lost. Use it in projects for data logging, clock-building, time stamping, timers, alarms, etc.
Since an Arduino microcontroller’s time keeping ability (millis()), is very limited in capability—i.e. can only keep track of time since its last power-up—it’s useful to have a separate RTC chip to keep a consistent count.
This module will keep track of time by seconds, minutes, hours, days, months, and year. You can program it to run either by 24-hour or 12-hour formats with AM/PM. It even accounts for months with less than 31 days and leap-years.
While the battery is not included (we recommend a coin cell battery), from this tiny RTC’s low power consumption you can expect it to run 5 years or more. If there is a power failure, the built-in power-sense circuit will automatically detect and switch to backup supply, preventing an interruption in time-keeping. It works best with 5V power.

Features:
    Consumes less than 500nA in battery-backup mode with oscillator running
    Automatic power-fail detection
    56-Byte, battery-backed, general-purpose RAM
    Backup by AT24C32 32Kbit
    I2C Serial Interface

For More Details on PC Click here

For More Details on Portables Click here.