Forget step counts using the accelerometer, the iPhone is about to become much more of a medical device if Apple gets the FDA & FCC's to approve its external heart-rate (HR) monitoring peripherals to feed into the iPhone. Although another device has already been cleared to accept HR via the Raisin Health Monitor, according to the USPTO application the device will be able to identify HR, the individual user, and even mood. Skip the mood ring, bring on the iPohone!
Using the detected signals, the electronic device can identify or authenticate the user and perform an operation based on the identity of the user. In some embodiments, the electronic device can determine the user's mood from the cardiac signals and provide data related to the user's mood.