These exist in smartwatches. Not reading your brain activity but tracking your micro movements (or macro) and vibrating on your wrist when you are in a lighter stage of sleep around your alarm time.

I believe this does actually exist but the most reliable one is from a company that went out of business, so you have to buy second hand

Edit: Its the Zeo Sleep Manager

Along somewhat similar lines, I wouldn't mind a fan that monitored my temperature while sleeping and adjusts its speed accordingly.

Similarly I want something that I can set to put me to sleep for X hours guaranteed. Insomnia is a bitch and ambien is awful. I just want to get ready for bed, set my alarm, and wake up exactly when I need to.

Sounds like a fun Hack a Day-esque project for someone out there. If you can secure it well enough to stay in place while you sleep, can probably make something with a repurposed Star Wars Force Trainer headset, an Arduino, and some means of triggering an alarm (the fact that we're just out there selling EEG tech as a kids toy is nuts to me).

I just wake up a few minutes before my alarm due to my internal clock. Doesn't matter what time I go to bed.