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 breakout Technical Details Revision History: As of October 2022 – we've updated this PCB with Adafruit Pinguin to make a lovely and legible silkscreen - you may get the new PCB or the older version with vector fonts - both are identical other than the fancy silkscreen. We also may have a slim metal or chunky plastic 32.768KHz crystal placed, both are functionally identical. 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