One beauty of a smart phone is just before laying down to sleep, just ask your phone to set an alarm in eight hours, and put it well out of your reach. And don't get back into bed (or the couch) when you get up to cancel the alarm. Just get moving.

I have done this when I got caught up in a really good book and read until 4:00 AM. Generally, I wake up on my own, before the alarm goes off, but it is a safety valve.