MONITORING FIT OF WEARABLE DEVICES
Tightness of a wearable device can be evaluated through direct observations of how the device responds to a physical stimulus. For example, by applying a haptic stimulus to a device strapped to a wrist or other body part, the optical response of the device can be measured to infer the amount of tension that is retaining the device against the body, or more generally, to evaluate whether the device is properly fitted to a user. Results can then be presented to a user objectively using Newtons or some other metric, or subjectively by providing qualitative assessments of fit. Recommendations for adjustments may also or instead be provided to the user for optimal performance of the wearable device.
1 . A computer program product comprising computer executable code embodied in a non-transitory computer readable medium that, when executing on one or more computing devices, performs the steps of:
causing a vibration of a wearable heart rate monitor coupled to a body of a user with an elastic strap by activating a haptic output element on the wearable heart rate monitor;
measuring an optical response from one or more optical sensors of the wearable heart rate monitor to the vibration;
calculating a level of optical coupling of the wearable heart rate monitor to the user with a signal from the one or more optical sensors;
calculating a tension of the elastic strap of the wearable heart rate monitor about the body by applying a physical model for the wearable heart rate monitor and the elastic strap to the level of optical coupling; and
providing adjustment information to the user based on the tension indicating whether the tension is within an acceptable range.
2 . The computer program product of claim 1 , wherein the physical model is a resonance model.
3 . A method comprising:
causing a vibration of a wearable monitor coupled to a body of a user;
measuring a response of the wearable monitor to the vibration;
calculating a level of optical coupling of the wearable monitor to the user with a signal from one or more optical sensors;
evaluating a fit of the wearable monitor to the body based on the level of optical coupling; and
providing adjustment information to the user to adjust the fit to a predetermined target.
4 . The method of claim 3 , wherein the predetermined target includes a tension in a band securing the wearable monitor to the user.
5 . The method of claim 3 , wherein the predetermined target includes a normal force of the wearable monitor against a skin of the user.
6 . The method of claim 3 , wherein calculating the level of optical coupling includes calculating the level of optical coupling based on a cross-correlation between the signal from the one or more optical sensors and a motion signal from one or more motion sensors.
7 . The method of claim 3 , wherein causing the vibration includes activating a haptic output element coupled to the wearable monitor.
8 . The method of claim 3 , wherein calculating the level of optical coupling includes calculating the level of optical coupling with a processor on the wearable monitor.
9 . The method of claim 3 , wherein providing the adjustment information to the user includes presenting the adjustment information in a user interface of a computing device associated with the user.
10 . The method of claim 3 , wherein the adjustment information indicates a tightness of the wearable monitor.
11 . The method of claim 3 , wherein the adjustment information includes an instruction for adjusting the wearable monitor about the body.
12 . The method of claim 3 , wherein measuring the response includes receiving optical data during the vibration from one or more light detectors.
13 . The method of claim 3 , wherein causing the vibration includes activating a linear haptic output element.
14 . The method of claim 3 , wherein the wearable monitor includes a wrist-worn monitor coupled to a wrist of the user with a wristband.
15 . The method of claim 3 , wherein the wearable monitor is secured in contact with the body with an elastic article of clothing.
16 . A system comprising:
a wearable monitor including at least one optical sensor and a haptic output element; and
one or more processors configured by computer executable code stored in one or more memories to test a fit of the wearable monitor by performing the steps of:
causing a vibration of the haptic output element,
receiving an optical response to the vibration from the at least one optical sensor, and
calculating a level of optical coupling of the wearable monitor about a body of a user based on the optical response to the vibration,
evaluating the fit of the wearable monitor to the user based on the level of optical coupling, and
communicating adjustment information to the user based on a difference between the fit and a predetermined target fit for the wearable monitor.
17 . The system of claim 16 , wherein evaluating the fit includes comparing the fit to one or more predetermined thresholds.
18 . The system of claim 16 , wherein the one or more processors include a first processor executing on the wearable monitor.
19 . The system of claim 16 , wherein the one or more processors include a first processor executing on a remote server coupled in a communicating relationship with the wearable monitor.
20 . The system of claim 16 , wherein the one or more processors are configured to automatically test the fit of the wearable monitor in response to detecting a deterioration in data quality below a predetermined threshold while the wearable monitor is being worn.