Abstract: Methods, systems, and devices for adaptive sensors are described. A system may acquire physiological data from a user via multiple optical channels of a wearable device, where each optical channel includes a light-emitting component and a photodetector. The system may determine respective measurement quality metrics and respective power consumption metrics associated with each optical channel based on the physiological data. Additionally, the system may select one or more optical channels of the multiple optical channels of the wearable device based on a comparison of the respective measurement quality metrics and the respective power consumption metrics associated with each optical channel. The system may acquire additional physiological data using the one or more optical channels based on the selecting.

Abstract: Methods, systems, and devices for determining blood pressure based on morphological features of pulses are described. A system may include a wearable device that uses one or more light emitting components configured to emit light, one or more photodetectors configured to receive light, and a controller that couples the one or more light emitting components to the one or more photodetectors. The wearable device may transmit lights associated with multiple wavelengths, and acquire photoplethysmogram (PPG) data that includes one or more PPG waveforms associated with the respective wavelengths. The system may determine respective sets of morphological features associated with each of the PPG waveforms based on systolic and diastolic peaks corresponding to the heartbeat of the user. The system may determine one or more blood pressure metrics for the user based at least in part on a comparison of the respective sets of morphological features.

Abstract: Methods, systems, and devices for hardware noise filtering are described. A wearable device may emit light from a set of light emitting elements (e.g., light emitting diodes (LEDs)) based on a known input signal. The wearable device may measure an output signal at a set of photodetectors. The output signal may be generated by passing the light emitted from the set of light emitting elements into a material in contact with the wearable device. The wearable device may compare the known input signal to the output signal and may determine a hardware noise component of the output signal based on a known environmental noise component of the output signal and the comparison. The wearable device may store the hardware noise component for filtering hardware noise from sensor measurements.

Abstract: Methods, systems, and devices for wearing detection are described. A wearable device may perform a measure of oxygen saturation (e.g., blood oxygen saturation (SpO2)) in a first series of measurements and a second series of measurements at a first locality of an anatomical feature of the user and a second locality of the anatomical feature of the user, respectively. The wearable device may send the first series of measurements and the second series of measurements to a user device of the user. The user device may determine an oxygen saturation calibration by comparing the first and second series of measurements. The user device may calibrate the second series of measurements according to the oxygen saturation calibration.

Abstract: Methods, systems, and devices for wearing detection are described. A user device may determine a condition to trigger an oxygen saturation measurement, or a measure of blood oxygen saturation (SpO2), for a user of a wearable device. The condition may be based on a physical state of the wearable device, a physiological state of the user, or both. In some examples, the user device may determine the condition based on one or more relationships between sensor data from the wearable device, application data, physiological data from the wearable device, or any combination thereof. The user device may receive a measure of oxygen saturation of the user from the wearable device. The user device may cause a graphical user interface (GUI) of the user device to display an indication of the measure of the oxygen saturation for the user.

Abstract: Methods, systems, and devices for blood oxygen measurement are described. A method may include receiving, via a wearable device, a first photoplethysmogram (PPG) signal for a user acquired during a time interval using a first set of PPG sensors, and receiving a second PPG signal for the user acquired during the time interval using a second set of PPG sensors that are different from the first set of PPG sensors. The method may include comparing the first PPG signal and the second PPG signal, and determining one or more blood oxygen saturation metrics for the user during the time interval based on the comparison of the first PPG signal and the second PPG signal. The method may include causing a graphical user interface (GUI) to display an indication of the one or more blood oxygen saturation metrics.

Abstract: Methods, systems, and devices for optical signal measurement are described. A wearable electronic device may activate a first combination of optical sensors, the first combination of optical sensors including a set of transmitter sensors and a set of receiver sensors. In some cases, one or more optical sensor of the first combination of optical sensors may be positioned under a protrusion on an inner surface of the wearable electronic device. The device may measure, at the set of receiver sensors at a first time, one or more signals from the set of transmitter sensors, determine a signal quality metric associated with the one or more signals, and select a second combination of optical sensors for use at a second time based on the signal quality metric.