I have listed my MCP79412 Real-Time Clock/Calendar breakout board as a Fundraiser on Tindie
I am hand-assembling the boards in batches. Once the Fundraiser minimum is met, I will order boards and parts. Check the Updates section on Tindie for current status.
The Microchip MCP79412 RTCC offers several advantages over other low-cost real-time clocks. Among these are on-chip calibration, dual alarms, power fail/restore timestamps, 64-bit unique ID, 128 bytes EEPROM, 64 bytes battery-backed SRAM, power supply 1.8 - 5.5V, I2C clock frequency to 400kHz.
I have written an Arduino library to support the MCP79412, which is available on github. (For other applications, the MCP79412 uses a standard I2C interface.) This is an open-source project (CC BY-SA), please see my blog post
for code, Eagle files, and additional information.