DS1339 Real Time Clock Module
Created with EAGLE v9 - Information here including a free version - https://www.autodesk.com/products/eagle/overview
If you simply want to order this board, here is an OSHPark link: https://oshpark.com/shared_projects/rNxANV7V
This is a basic implementation of the Maxim DS1339 Real Time Clock. The I2C and Interrupt pins are all presented on a 6-pin header. There is also a 2-pin header to allow for other sources of battery backup power should you not chose to use the CR1225 coin cell on the back.
This is open source hardware, please feel free to use and improve according to the attached license. This hardware was developed by See Insights LLC for a project sponsored by Jay Ham, Colorado State University - Thank You!
The original library by Shridhar Rajagopal - https://github.com/sridharrajagopal/DSRTCLib
An adaptation of Shridhar's project I made for the Particle platform - https://github.com/chipmc/RTC-Watchdog