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 to adjust at least one setting for operating the heart rate monitor, wherein operating the heart rate monitor comprises:
(a) operating a light source in the heart monitor in a skin characterization mode by emitting a succession of light pulses, at least some having variable intensity with respect to one another; (b) detecting a variation in intensity of light from the light pulses emitted in the skin characterization mode after the light has interacted with the user's skin; (c) determining a response characteristic of the user's skin from the variation in intensity of light detected in (b); and (d) using the response characteristic of the user's skin to adjust a gain and/or light emission intensity of the heart rate monitor operating in a first mode for detecting one or more characteristics of the user's heartbeat waveform, wherein at least (b) and (c) are carried out by a processor, and wherein operating in the first mode comprises pulsing the light source in the heart rate monitor at a first frequency and detecting light from the light source, after the light has interacted with the user's skin, at the first frequency, and wherein operating in the skin characterization mode comprises pulsing the light source in the heart rate monitor at a second frequency, which is different from the first frequency, and detecting light from the light source at the second frequency.