Ask HN: Most effective and "non-invasive" morning wake up alarm method?

Seriously folks. Those with evening circadian rhythms will understand (and those without might appreciate) the question. Throwing this out there for your help on this: Is there an effective yet least jarring alternative to early morning alarms than the traditional alarm clock? Are we doomed to starting the day with the equivalent of a gunshot?

Interested in any and all alternatives that might exist, even in learning about morning routines that work for you