Adafruit 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 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. We recommend you purchase a coin cell battery to use with this product.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 our affordable PCF8523 RTC breakoutCheck out our detailed guide for wiring diagrams, schematics, fritzing objects, library code and more! 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