Save some space in your dorm and leave an AC plug open for other gadgets. Many smartphone apps come with more robust features than your standard alarm. For example, Sleep Time for iOS is one of several apps that detect your movements while you're sleeping to determine what phase of sleep you're in. As a result, the app prompts your phone to wake you at exactly the right moment, and also comes with an Instant Heart Rate meter to measure your pulse when you awaken. Granted, alarm clocks can come as cheap as $10 to $20, but that's still more than you'd be paying for an app like Sleep Time, which costs $1.99.
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