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 one or more processors, 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 operating in the skin characterization mode comprises: (i) emitting a plurality of light pulses using the light source in the heart rate monitor, (ii)detecting the plurality of light pulses using the light detector in the heart rate monitor after the plurality of light pulses interact with the user's skin, (iii) generating a plurality of data points, each data point comprising an intensity value of a respective light pulse of the plurality of light pulses as emitted in (i) and an intensity value of the respective light pulse of the plurality of light pulses as detected in (ii) that corresponds to the emitted light pulse of the plurality of light pulses as emitted in (i), and (iv) fitting a mathematical relationship to the plurality of data points; (b) using the mathematical relationship to determine a light source emission intensity setting that provides a pre-determined light detection level; and (c) adjusting a light source emission intensity to said light source emission intensity setting determined in (b) for operating in the first mode.