Calibration & battery update 2023-09-27

A project log for Remarkably Accurate Quartz Clock

Shooting for 10 sec/year accuracy with an ATmega and software-based, temperature-aware frequency correction

gaborGabor 09/28/2023 at 09:580 Comments

In 5 weeks the clock became 1.5 seconds late. This is an accelerating rate of drift after the many stable months leading up to the previous calibration! The updated error has gone from -6.37 PPM to -6.85 PPM. Extrapolating the currently corrected error, this would be about 15 seconds late per year.

Battery is sinking noticeably too, now below the 3 V line at 2.998 V.