Adafruit DS1307 Real Time Clock Assembled Breakout Board

Adafruit 3296 - DS1307 Real Time Clock Assembled Breakout Board 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 it has been used with 5V power and 3.3V logic successfully) Works great with an Arduino using Adafruit's 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 The DS1307 is simple and inexpensive but not a high precision device. It may lose or gain up to 2 seconds a day. For a high-precision, temperature compensated alternative, please check out the DS3231 precision RTC. If you do not need a DS1307, or you need a 3.3V-power/logic capable RTC please check out the affordable PCF8523 RTC breakout Required Battery (Not Included) CR1220 Coin Cell Technical Details Dimensions: Length: 25.8mm/1.02in Width: 21.7mm/0.85in Height: 5mm/0.2in Weight: 2.3g/0.09oz Mounting holes are 2.2mm(0.086in) diameter, 25mm(0.98in) apart This board/chip uses I2C 7-bit address 0x68