in one aspect of the teachings herein , a physical activity tracking system includes a wearable electronic device that uses dual touch points for detecting control inputs by a user . processing within the device complements the dual touch point interface by requiring simultaneous touch detections to register user inputs to the device , and by mapping dual - touch detections of different duration to different control actions . use of the dual - touch arrangement and the associated processing provides a number of advantages , including intuitive operation and minimization of accidental activations by the user . other advantages of the touch interface include the ability to seat or mount the device in a variety of carriers , such as bracelets , etc ., that complement wearability of the device , while still allowing for convenient charging .