A little toy project I started a while ago. Simulating the WWV audio broadcast on a esp32 based M5stack. Automatically sets UTC time via gps, as well as has local database lookup for local time display. It is by no means "time nuts" quality, but does discipline the audio dma buffer to the gps PPS for "ticks" within a single audio sample of accuracy. Added automatic leap second support via gps information for added fun.
Oh yeah, wait till the end (also includes the voice announcement)
https://youtu.be/IL36d7pj_qc