About the alarm. The alarm is more accurate.
As a child, I was fascinated by radio hobbyism, well, in the sense of listening to the radio and spinning radio details in the name of progress. I got caught up by chance, but it turned out – for the rest of the time...Where I taught Morse’s alphabet, there was a collective radio station and the elderly guys were talking to different countries. It was 1976! Then there were no televisions in the country, and some had them at home...After radio communication with a new country, a bulldozer with a flag was stuck into the world map and everyone was jealous of the one who made such a feat. In short, the line to work at the radio station was around the clock and I, as the youngest, once or twice a week got two hours, but at the very "this" time - 3 or 5 nights-morning. No alarm clock could beat the school sleep, and in the morning he almost cried that he had spent his time on the radio station. I honestly don’t remember who gave me the advice. The advice is this: before going to bed, already in bed, 3-5 times mentally (at the same time it is desirable to look at the clock sheet) say - "I wake up at... hours", then knock your left foot on the wall and... all - sleep. It worked from the first time, as if someone had pushed at three o’clock in the night. And it has been working for more than thirty years. The mechanism of this phenomenon is unknown, and not very much wanted...