I would not call that a hack: many timekeeping systems rely on this principle. There was a great write up on Hackaday: https://hackaday.com/2018/03/29/ask-hack

I would not call that a hack: many timekeeping systems rely on this principle. There was a great write up on Hackaday: https://hackaday.com/2018/03/29/ask-hackaday-is-your-clock-tied-to-mains-frequency/ https://hackaday.com/2018/03/29/ask-hackaday-is-your-clock-t...