Is This the World's Most Perfect Alarm Clock?

The only thing worse than waking up for work is being jarred awake by the sound of your partner’s alarm clock ... well before you actually need to get up. The new Lark alarm clock and sleep sensor solves that problem, as long as you don’t mind shelling out $129—and you have an iPhone. The sleep sensor, which is worn in a wristband and connects wirelessly to your phone, gently and silently vibrates at your preferred wake-up time so that your partner isn’t disturbed.

As an added bonus, the vibration doesn’t cause the adrenaline rush of a typical alarm clock, meaning you’ll be less likely to crash later in the day, according to the experts who developed it. The vibration also changes each day, making it more difficult to ignore; but if you do, the iPhone acts as a back-up, playing a tune specific to Lark. The sensor also measures quality of sleep and tracks sleep patterns when coupled with a free app; for $60 more, you get a seven-day sleep assessment and personalized advice. Katherine Boehret had her fiancé test out the device, which was developed with the help of a Harvard sleep expert and a sleep coach for pro athletes, and writes in the Wall Street Journal that it "worked like a charm. I was so undisturbed in the morning, I didn't notice him getting out of bed. " (And, yes, there is a snooze button.)