Athletic performance monitoring system utilizing heart rate information
An illumination source may be configured to illuminate the skin of the user. An illumination detector may detect electromagnetic radiation reflected of the skin of the user. A compensation module may be configured to determine the position of the skin of the user relative to the illumination detector. A processor may be configured to determine a heart rate of the user by analyzing information corresponding to an amount of the electromagnetic radiation detected by the illumination detector. The processor may also determine the heart rate of the user by compensating for the position of the skin of the user as determined by the compensation module.
1. An optical detector comprising:
a first illumination source module that includes a first near-field light-emitting diode (LED) configured to provide infrared (IR) illumination and a first far-field LED configured to provide IR illumination;
a second illumination source module positioned substantially orthogonal relative to the first illumination source module that includes a second near-field LED configured to provide IR illumination and a second far-field LED configured to provide IR illumination;
an illumination detector comprising a photodiode positioned proximate to the first near-field LED and the second near-field LED and configured to detect an amount of IR radiation reflected off skin of a user;
a first pair of lens elements configured to focus the IR illumination provided by the first and second near-field LEDs such that the IR illumination achieves maximum reflection off the skin of the user with the skin positioned a first distance from the illumination detector;
a second pair of lens elements configured to focus the IR illumination provided by the first and second far-field LEDs such that the IR illumination achieves maximum reflection off the skin of the user with the skin positioned a second distance, greater than the first distance, from the illumination detector;
an interface configured to provide information corresponding to the amount of IR radiation reflected off the skin of the user;
wherein the photodiode is offset from at least one centerline of the optical detector and positioned proximate to a corner of the optical detector; and
wherein the first illumination source module is positioned proximate to a first edge of the optical detector and is oriented in a first direction along the first edge, and the second illumination source module is positioned proximate to a second edge of the optical detector and is oriented in a second direction along the second edge, the second direction being substantially orthogonal to the first direction.
2. The optical detector of claim 1 wherein the optical detector is incorporated into a heart rate determination system that determines a heart rate of the user based, at least in part, on the information corresponding to the amount of IR radiation reflected off the skin of the user.
3. The optical detector of claim 2 wherein the heart rate determination system is incorporated into a wrist-worn device that is configured to measure movements of an individual wearing the wrist-worn device.