Abstract: A wearable device, such as a wearable ring device, configured to transition between multiple discrete ring sizes is disclosed. The wearable ring device may include a discontinuous ring-shaped housing that extends radially around at least a portion of a circumference of the wearable ring device, where a first end and a second end of the discontinuous ring-shaped housing are separated from one another by a radial distance and configured to move relative to one another. The wearable ring device may further include one or more sensors positioned at least partially within an inner circumferential surface of the discontinuous ring-shaped housing, and one or more mechanical components configured to transition the wearable ring device between the multiple discrete ring sizes.

Abstract: A wearable device, such as a wearable ring device, configured to transition between multiple discrete ring sizes is described. For example, the wearable ring device may include multiple rings coupled to one another (e.g., adjacent, parallel, or concentric rings), where a user may manipulate or adjust the rings relative to one another to transition between multiple discrete ring sizes. In some cases, the multiple rings may be oval or elliptical-shaped, where rotating the rings relative to one another may change the size of the ring. In some other cases, the multiple rings may be threaded such that they may be screwed into and out of one another. In some other cases, the wearable ring device may include a long housing that may coil into itself to form multiple concentric loops, where coiling or uncoiling the concentric loops adjusts the ring size.

Abstract: A wearable device, such as a wearable ring device, configured to transition between multiple discrete ring sizes is described. For example, the wearable ring device may have an adjustable inner circumference and a rigid outer housing. The inner circumference may be adjusted to transition between multiple discrete ring sizes. For example, a wearable ring device may include a ring housing that exhibits a constant outer circumference, where mechanical components of the ring are configured to adjust at least a portion of an inner circumferential surface to transition the ring between the discrete sizes. The ability of the wearable device to transition between multiple discrete sizes may enable the wearable device to achieve a better fit on a user, thereby improving contact between one or more sensors of the wearable device and the skin of the user, leading to more accurate physiological data readings.

Abstract: Methods, systems, and devices for adjusting a power output level of a light source on a wearable device are described. A photodetector on the wearable device may measure a first photoplethysmography (PPG) signal derived from an ambient light source that is powered externally to the wearable device. The wearable device may calculate a quality metric of the first PPG signal based on measuring the first PPG signal. The wearable device may adjust the power output level of the light source powered by the wearable device based on the quality metric of the first PPG signal.

Abstract: Methods, systems, and devices for contact detection for a wearable device are described. The system may measure, by the one or more optical components, a photoplethysmogram (PPG) signal for a user of the wearable device and detect a change in the PPG signal or a change in morphology between cardiac pulse waveforms that are based on the PPG signal and reference cardiac pulse waveforms. In some cases, the system may determine, based on the change in the PPG signal or the change in morphology coinciding with a change in a metric measured by the wearable device, that the change in the PPG signal or the change in morphology is based on a change in contact between the wearable device and the skin of the user of the wearable device. The system may output the PPG signal and an indication of the change in contact.

Abstract: Methods, systems, and devices for identifying representative photoplethysmogram (PPG) pulses are described. A method may include acquiring a first set of PPG pulses from a user via a wearable device. The method may include comparing a set of morphological features of the first set of PPG pulses, and determining one or more PPG profiles for the user, where the one or more PPG profiles each include a set of morphological value ranges for the set of morphological features. The method may include acquiring a second set of PPG pulses from the user via the wearable device, and determining that one or more PPG pulses from the second set of PPG pulses match the one or more PPG profiles. The method may include determining one or more physiological metrics associated with the user based on the one or more PPG pulses matching the one or more PPG profiles.

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: A wearable device is described. The wearable device may be constructed of one or more flexible materials, and may be referred to as a flexible wearable device. The flexible wearable device may include a flexible housing that is made of a material that is elastically deformable, where the flexible housing at least partially surrounds components of the flexible wearable device. The flexible housing may include apertures disposed within the surface of the flexible housing to enable light to be transmitted and received through the flexible housing. The flexible wearable device may also include a printed circuit board (PCB) disposed within the flexible housing (e.g., within a cavity formed by the flexible housing). The PCB may include sensors configured to acquire physiological data from a user by transmitting light and receiving light through the apertures. The PCB may be constructed of flexible regions that are elastically deformable.

Abstract: Methods, systems, and devices for analyzing fluid using a wearable device are described. The method may include collecting a bodily fluid of a user using a fluid collection component that includes one or more measurement channels configured to change color when exposed to the bodily fluid. Further, the method may include transmitting light associated with one or more wavelengths and generating one or more signals based on the light reflected off the one or more measurement channels of the fluid collection component and received by a wearable device. Moreover, the method may include determining a color of the one or more measurement channels based on the one or more signals and determining a presence or concentration of one or more substances within the bodily fluid based on the color.

Abstract: Methods, systems, and devices for measurement multiplexing for a wearable device are described. The method may include transmitting light using a light-emitting component of a wearable device via a set of transmission angles and receiving the light using a photodetector of the wearable device via a set of reception angles. Further, the method may include selecting a transmission angle from the set of transmission angles and a reception angle from the set of reception angles based on a comparison of a set of signal quality metrics associated with the set of transmission angles and the set of reception angles. The method may further include acquiring physiological data associated with the user using the transmission angle and the reception angle.

Abstract: Methods, systems, and devices for manufacturing a device are described. The manufacturing system may assemble a plurality of optical components onto an inner circumference of an inner housing member of a wearable ring device and align the plurality of optical components with a plurality of apertures of the inner housing member. In some cases, the manufacturing system may position a plurality of optoelectronic components affixed to a flexible printed circuit board onto the inner circumference after the plurality of optical components are assembled onto the inner circumference. The manufacturing system may adhere the plurality of optoelectronic components to the plurality of optical components such that the plurality of optical components are aligned with the plurality of optoelectronic components.

Abstract: Methods, systems, and devices for measuring a skin tone using a wearable device are described. The method may include the wearable device transmitting, using one or more light-emitting components, first light associated with a first wavelength, second light associated with a second wavelength, and third light associated with a third wavelength and generating a first signal, a second signal, and a third signal based on the first light, the second light, and the third light, respectively, received at one or more photodetectors of the wearable device, Further, the method may include the wearable device determining a first difference between the first signal and the second signal, and a second difference between the first signal and the third signal and determining a skin tone metric associated with the user based on a comparison between the first difference and the second difference.

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 manufacturing a wearable device are described. A method for manufacturing a wearable device may include coupling a printed circuit board (PCB) to an inner ring-shaped housing that contains a plurality of apertures by aligning a plurality of sensors of the PCB with the plurality of apertures. The method may also include coupling an outer ring-shaped housing to the inner ring-shaped housing by surrounding the inner ring-shaped housing with the outer ring-shaped housing. Additionally, the method may include injecting a filler material through an additional aperture of the outer ring-shaped housing to fill a cavity defined by the inner ring-shaped housing and the outer ring-shaped housing, filling at least a portion of the plurality of the inner ring-shaped housing with the filler material.

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: A wearable device is described. The wearable device may be constructed of one or more flexible materials, and may be referred to as a flexible wearable device. The flexible wearable device may include a flexible housing that is made of a material that is elastically deformable, where the flexible housing at least partially surrounds components of the flexible wearable device. The flexible housing may include apertures disposed within the surface of the flexible housing to enable light to be transmitted and received through the flexible housing. The flexible wearable device may also include a printed circuit board (PCB) disposed within the flexible housing (e.g., within a cavity formed by the flexible housing). The PCB may include sensors configured to acquire physiological data from a user by transmitting light and receiving light through the apertures. The PCB may be constructed of flexible regions that are elastically deformable.

Abstract: Methods, systems, and devices for wearable device are described. A wearable device may include a first light-emitting component positioned within an inner circumferential surface of the wearable device at a first radial position and a second light-emitting component positioned within the inner circumferential surface of the wearable device at a second radial position, where the first radial position and the second radial position define a segment of the inner circumferential surface between the first radial position and the second radial position. Additionally, the wearable device may include a photodetector configured to receive light emitted by the first light-emitting component and the second light-emitting component. In some cases, the photodetector may be positioned at a third radial position within the segment of the inner circumferential surface between the first radial position and the second radial position, where the third radial position is offset from a radial midpoint of the segment.

Abstract: Systems and devices for optimized structures for optical measurement are described. A wearable device may include a housing configured to house one or more sensors to acquire physiological data from a user. The wearable device may further include one or more light sources disposed on a surface of the housing and positioned to direct light into a tissue surface of the user and one or more detectors disposed on the surface of the housing and positioned to receive light from the one or more light sources along a plurality of optical paths where a first optical path may be through the tissue surface and a second optical path may be directly from the one or more light sources. The wearable device may include one or more light blocking components disposed on a surface of the housing that are configured to block stray light along the second optical path.

Abstract: Methods, systems, and devices for implementing an artificial artery to calibrate a wearable device are described. An artificial digit may be formed from a material configured with optical properties, thermal properties, or mechanical properties representative of human tissue (e.g., a human finger). The artificial digit may include one or more channels representative of human arteries, capillaries, or both. Additionally, or alternatively, the artificial digit may include electrochromic sheets that may adjust to light absorption properties of the material. A wearable device may be placed on the artificial digit, and one or more sensors of the wearable device may be activated to collect measurements when there is simulated fluid flow through the artificial digit (e.g., via a pump system). The wearable device sensors may be configured, or calibrated, according to the measurements.