Why does Ken’s alarm ring early? It is a smart alarm. This alarm watches his sleep. It looks for light sleep. Light sleep means easier waking. Ken sets his wake-up time. In the morning, his phone checks movement. Then it rings a little early. Ken opens his eyes. He feels less shocked than usual. But here is the turn. The phone can make mistakes. It only guesses his sleep. So Ken still goes to bed early. A smart alarm can help. Good sleep starts before the alarm.