[jcdreads]

Any wrist-mounted Fitbit will do this, even the tiny ones without a screen. I've been using one as my only alarm for about a year, and it works great.

Disclaimer: I work for Fitbit.

Edit: Also, the battery needs a 90-minute charge only once or twice a week.

[jwong_]

Fitbits don't do smart alarms, which is what he's asking for. He wants an alarm to wake up him roughly around the end of a sleep cycle. No fitbit currently has this feature at all.

I was confused since I was sure it didn't have this feature. Had to look it up to make sure.