WEARABLE HEART RATE MONITOR

摘要

Some embodiments provide a wearable fitness monitoring device including a motion sensor and a photoplethysmographic (PPG) sensor. The PPG sensor includes (i) a periodic light source, (ii) a photo detector, and (iii) circuitry determining a user's heart rate from an output of the photo detector. Some embodiments provide methods for operating a heart rate monitor of a wearable fitness monitoring device to measure one or more characteristics of a heartbeat waveform. Some embodiments provide methods for operating the wearable fitness monitoring device in a low power state when the device determines that the device is not worn by a user. Some embodiments provide methods for operating the wearable fitness monitoring device in a normal power state when the device determines that the device is worn by a user. Some embodiments provide methods for using response characteristics of the user's skin to adjust a gain and/or light emission intensity of the heart rate monitor.

主权项

1. A method of operating a heart rate monitor of a wearable fitness monitoring device, wherein the heart rate monitor comprises a light source and a light detector, the method comprising:
(a) operating the heart rate monitor in a first mode while also operating in a skin characterization mode for determining a characteristic of a user's skin, wherein the first mode is configured to determine one or more characteristics of the user's heartbeat waveform, and wherein the skin characterization mode comprises generating data points representing emission intensity from the light source and corresponding detection levels from the light detector; (b) fitting the data points of the skin characterization mode to a mathematical relationship relating light source emission intensity to light detector detection level; (c) using the mathematical relationship to determine a light source emission intensity setting that provides a pre-determined light detector detection level identified as providing good heart rate monitor performance; and (d) adjusting the light source emission intensity to said setting determined in (c) for operating in the first mode.