Patent Publication Number: US-2021169345-A1

Title: Ring for optically measuring biometric data

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/439,467, filed on Jun. 12, 2019, entitled “RING FOR OPTICALLY MEASURING BIOMETRIC DATA.” The disclosure of this application is herein incorporated by reference in its entirety for all purposes. 
    
    
     BACKGROUND 
     Recent advances in technology, including those available through consumer devices, have provided for corresponding advances in health detection and monitoring. For example, devices such as fitness bands and smart watches are able to determine information relating to the health of a person wearing the device. One use of these devices is to detect pulse oximetry. Pulse oximetry is a noninvasive method for monitoring a person&#39;s oxygen saturation and can be useful in monitoring a variety of health conditions. Traditional devices for monitoring oxygen saturation which are found in hospitals are typically tethered and are generally uncomfortable and unsuitable for normal wear. Smart watches and other “smart” devices that have attempted to measure oxygen saturation are generally less reliable and have limited battery life. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various embodiments in accordance with the present disclosure will be described with reference to the drawings, in which: 
         FIG. 1  illustrates an example ring according to various embodiments. 
         FIGS. 2A-2E  illustrates example light source and photodetector configurations according to various embodiments. 
         FIG. 3  illustrates an example cross section of the ring and finger according to various embodiments. 
         FIGS. 4A-4D  illustrates example light techniques for controlling light according to various embodiments. 
         FIG. 5  illustrates an example organizational diagram for example components within a ring according to various embodiments. 
         FIGS. 6A and 6B  illustrate example techniques for retrieving data from the ring according to various embodiments. 
         FIG. 7  illustrates an example method according to various embodiments. 
         FIG. 8  illustrates components of an example computing device that can be utilized in accordance with various embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, various embodiments will be described. For purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the embodiments. However, it will also be apparent to one skilled in the art that the embodiments may be practiced without the specific details. Furthermore, well-known features may be omitted or simplified in order not to obscure the embodiment being described. 
     Approaches in accordance with various embodiments provide for the measurement of biometrics using a ring placed on a digit, such as a user&#39;s finger. The ring can comprise a compact housing including light source(s) for sending light through, or towards, the finger and photodetector(s) for detecting the light that is reflected from and/or transmitted through at least a portion of the finger. The combination of the light source(s) and the photodetector(s) can be used to detect absorption of light at, for example, one wavelength in comparison to light at another wavelength. The different rates of absorption can be used to calculate biometric data, such as the oxygen saturation. Such a ring-shaped device can monitor other biometric information as well, and can transmit the biometric information to another device for further analysis, display, or other such usage. 
     Various other functions can be implemented within the various embodiments as well as discussed and suggested elsewhere herein. 
     Many portable electronic devices such as smart watches include functionality for measuring various biometric information. For example, many include capability for measuring oxygen saturation using reflective techniques. For example, an LED and a photodetector might be on an inward facing side of a smart watch. The LED can illuminate a user&#39;s skin and the photodetector can detect light that reflects back towards the watch. This approach however suffers significant drawbacks. One problem is that an interior surface of a watch does not always rest flush against the skin of the wearer. While reflective detection might generally provide more noisy data in comparison to transmissive detection, the noise can be exacerbated when there is not contact with the skin and the exterior surface of the skin reflects light towards the photodetector  202 . Another problem with traditional smart devices is that they have limited battery life. Because they include display screens and other functionality outside of biometric monitoring, their battery life is limited to typically less than a day. A limited battery life makes all-day monitoring impossible. For example, if a user wears their smart watch during the day, they will likely recharge their watch at night. This is problematic for users who wish to monitor their oxygen saturation throughout the day and night. 
     Dedicated oxygen saturation measurement devices are traditionally unsuited for casual every-day type of wear. For example, they are typically clamped onto the tip of the finger thus preventing the user from performing typical daily operations such as grabbing items, typing, etc. Further, these devices are typically tethered to an external power source or external processing equipment which severely limits the mobility of the user. 
     The present solution enables users to wear a biometric device in such a way to accommodate their lifestyle. Disclosed herein is a ring with a light source and a photodetector directed inwards on a ring. The ring can thus detect oxygen saturation of a wearer based on light transmitted through the wearer&#39;s finger. The ring can include power saving measures to extend the battery life. A motion sensor can help determine opportune moments for data collection such as when the wearer is still. The motion sensor can be used to remove noise from the data caused by motion. After data is collected or during data collection, the ring can wirelessly communicate the data to another portable electronic device such as a phone or watch. In some embodiments, the data can be communicated over near field communications (NFC) protocol while the user is holding their phone and the ring is in close proximity to the phone. 
       FIG. 1  illustrates an example ring  104  according to various embodiments. For example, a user can wear a ring  104  on a finger of the user&#39;s hand  106 . The user can then connect to the ring  104  with a portable electronic device  102  such as a phone or watch. The ring  104  can collect biometric data and periodically send the data to the portable electronic device  102  for processing, display, and/or retransmission to a networked service. The ring  104  can implement power saving measures to prolong the battery life. The ring  104  can generally be in a low power state unless it is measuring data or transmitting data to another device, thus extending the battery life in comparison to traditional approaches. The battery life can be a few days to a number of weeks depending on use. 
     The ring  104  can be worn on a wearer&#39;s finger. The ring  104  can be worn between two knuckles of the finger. This can leave the tip of the finger unobstructed for common tasks. The thickness of the band can be minimized to accommodate free movement of the finger in relation to other fingers. In some embodiments, a larger ring can be designed which fits over the thumb of a wearer. In some embodiments, a combination of multiple rings can be utilized wherein each ring has different functionality. The multiple rings can be worn on the same finger in a stacked form or can be worn on separate fingers. In some embodiments, one ring can be worn on a first finger and a second ring can be worn on another finger. A two-fingered setup can include a flexible or rigid connection between the rings. If multiple rings are used, they can be in electronic communication through electric contacts that physically can touch or wireless communication using a wireless protocol. In some embodiments, the “ring  104 ” can be wider than a traditional ring  104  and can be a flexible sleeve worn on a user&#39;s finger. For example, the ring  104  can be like the finger of a glove. In some embodiments, features of the ring  104  can be added to a traditional ring  104 . For example, a light source  204 , photodetector  202 , and other elements can snap onto a traditional ring  104 . The ring  104  can have an opening that is elliptical or any other shape through which a digit can pass. In some embodiments, the device can envelop a digit, taking the form of a thimble, glove, etc. 
     It should be understood that the principles herein disclosed in relation to a ring  104  can be applied to rings  104  worn on other places aside from the finger as well as other systems. For example, an earring can be worn on a user&#39;s earlobe and can shine a light through the lobe for detection on the other side of the ear. The principles can also apply to a navel ring  104 , nose ring  104 , anklet, bracelet, device placed over the tip of a finger such as a soft thimble, etc. In some embodiments, the principles herein disclosed can be applied to a glove (e.g., a photodetector  202  can be on one side of the glove and a light source  204  can be on the other side; light can then be passed through the palm of the gloved hand). Similarly, the principles herein can be applied to a shoe or sock whereby a light source  204  can shine light through a toe or arch of a person&#39;s foot. 
     A user&#39;s portable electronic device  102  can periodically receive data from the ring  104  over a wireless communications protocol. The portable electronic device  102  can be a phone, smart watch, fitness tracker, etc. The portable electronic device  102  can receive data from the ring  104  once a second, minute, day, etc. In some embodiments the portable electronic device  102  polls the ring  104  to determine if there is new data to receive; additionally or alternatively the ring  104  can push new information to the portable electronic device  102  as it become available and/or according to a power policy. In some embodiments, the ring  104  can transmit data to a less portable electronic device such as a desktop computer or networked computer. For example, the ring  104  can send data to the portable electronic device  102  using a low power wireless protocol and the portable electronic device  102  can send the information to a networked server using a higher power wireless protocol (e.g., WiFi or cellular network). 
     The user experience can generally be seamless as the ring  104  can have an extended battery life and can automatically transmit data to a portable electronic device  102  that the user already owns and uses. Further, the ring  104  can provide more accurate biometric information that a smart watch or similar device because the ring  104  abuts the users skin more completely and reliably. 
       FIGS. 2A-2E  illustrate example configurations of a ring  104  according to various embodiments. The ring  104  can include a light source  204  and a photodetector  202 . For the purposes of these illustrations, the photodetector  202  is illustrated using an empty rectangle whereas the light source  204   104  is illustrated using a rectangle with a dark rectangle inside.  FIG. 1  illustrates how a single light source  204  can be located separately from a single photodetector  202 . 
     A system can utilize the ring  104  to monitor the oxygen saturation (SpO2), pulse, blood pressure, glucose levels, lipid concentration, carboxyhemoglobin levels, hemoglobin concentration (hematocrit levels), etc. In some embodiments, the ring  104  can monitor pulsatile (arterial) blood oxygenation (“SpO2”) or non-pulsatile (arterial and venous blood, usually called tissue oxygenation or “StO2”). These measurements can largely be taken by measuring the transmission and/or reflection of light through a user&#39;s finger. For example the light source  204  can emit light through the finger of a user which can be partially absorbed by the finger and then detected at the photodetector  202 . Based on which wavelengths of light are absorbed by the finger, the system can determine the oxygen saturation in the user&#39;s body. 
     Oxygenated hemoglobin (HbO2) absorbs red light and infrared light differently than deoxygenated hemoglobin (Hb). For example, HbO2 absorbs less red light than Hb while at higher wavelengths of light, HbO2 absorbs more light than Hb. By comparing the absorption of red to infrared light, a system can determine the SpO2 in the user&#39;s body. Measurements taken over time can help overcome noise in the data. For example, the system can identify a pulse in the data and use that as a baseline to compare for oxygen saturation calculations. 
     The ring  104  can utilize a light source  204  such as a light emitting diode (LED), a laser diode, filtered broadband light source, etc. A light source  204  can be used which emits a certain primary wavelength of light (e.g., infrared or red light). A light source  204  can be used which emits light according to a wide range of wavelengths (e.g., “white” light that mimics natural sunlight). In some embodiments, one or more filters can be placed on a light source  204  to limit the wavelengths of transmission. In some embodiments, multiple light sources  204  can be independently activated. For example, a red LED can be activated and then an infrared LED can subsequently be activated. In some embodiments, light guides can provide the light from a single light source  204  to various locations of the ring  104 . In some embodiments, ambient light is utilized as the light source  204 . For example, the ring  104  can detect ambient light that passes at least partially through a finger of the user. Other external light sources  204  are contemplated. 
     The ring  104  can utilize a photodetector  202  such as a photodiode and/or phototransistor to detect the amount of light that passes through a finger of a user from the light source  204 . The photodetector  202  can detect light reflected within the finger and/or transmitted through the finger. A photodetector  202  can be configured for a particular wavelength of light such as red or infrared light. For example, a photodetector  202  can have a filter configured to permit the particular wavelength to pass. In some embodiments, the photodetector  202  is not configured for a single wavelength of light but can be activated by multiple wavelengths of light. Such a configuration can be useful when multiple light sources  204  are used with corresponding wavelengths (e.g., a red light source  204  can be activated followed by an infrared light source  204 ). 
     In some embodiments, the light source  204  is positioned largely opposite of the photodetector  202  as shown in  FIG. 2A . This can facilitate transmissive readings of light that passes through the finger. In some embodiments, the light source  204  is positioned closer to the photodetector  202 . For example, the light source  204  can be positioned next to the photodetector  202 . This can facilitate reflective readings of the light that reflects off the interior of the finger. The placement of the light source  204  relative to the photodetector  202  can be varied to obtain a blend of transmissive and reflective readings. For example, if the photodetector  202  is placed at a 90 degree offset from the light source  204  (e.g., a quarter of the way around the ring  104 ), then a portion of the light that the photodetector  202  receives will be transmissive, passing directly from the light source  204  to the photodetector  202 , whereas a portion will be reflective, bouncing off the inside of the finger and arriving at the photodetector  202 . Other offsets are contemplated; for example, the photodetector  202  can be placed 10 degrees, 15 degrees, 30 degrees, 45 degrees, 110 degrees, etc. from the light source  204  (e.g., around the ring  104 ). 
     It should be understood that there can be multiple photodetectors  202  and multiple light sources  204 . Furthermore, it should be understood that a single photodetector  202  can be used to take readings from various light sources  204  and a single light source  204  can provide light to multiple photodetectors  202 . For example, if a ring  104  includes a photodetector  202  at its “top” (e.g., 0 degrees), it can include light sources  204  at 0 degrees, 45 degrees, 90 degrees, etc. around the ring  104 . These light sources  204  can be separately activated and read by the photodetector  202 . For example, the light source  204  at 0 degrees can be activated and recorded by the photodetector  202 ; the light source  204  at 45 degrees can then be activated and detected by the photodetector  202 , followed by the light source  204  at 90 degrees, and so on. Similarly, a single light source  204  (e.g., at 0 degrees) can emit light for detection at multiple photodetectors  202  around the ring  104  (e.g., at 0 degrees, 45 degrees, 90 degrees, etc.). Thus, multiple light sources  204  can be detected by multiple photodetectors  202 , in combination (e.g., multiple light sources  204  detected by a single photodetector  202  and/or a single light source  204  detected by multiple photodetectors  202 ) and/or in alternating groupings of light sources  204  and photodetectors  202 . By emitting and detecting light in various combinations, the system can help minimize noise in the data (e.g., from ambient light). Thus, multiple photodetectors can detect respective light paths from a single source, a single photodetector can detect multiple light paths from multiple light sources, etc. 
     In  FIG. 2B , a first location on the ring  104  can include a light source  204  and photodetector  202  and a second location on the ring  104  can include another light source  204  and photodetector  202 . The ring  104  can take a measurement using the top light source  204  and the bottom photodetector  202 . The ring  104  can then take measurements using various combinations of the light sources  204  and photodetectors  202 . Combinations can include the bottom light source  204  and the top photodetector  202 , the top light source  204  and top photodetector  202 , the bottom light source  204  and bottom photodetector  202 , the top and bottom light sources  204  and the bottom photodetector  202 , the top and bottom light sources  204  and the top photodetector  202 , the top and bottom photodetectors  202  and the top light source  204 , the top and bottom photodetectors  202  and the bottom light source  204 , and so on. Each combination can be activated for a period comprising a few milliseconds to a few seconds. For example, each combination can be activated multiple times during a single heartbeat. In some embodiments, each combination is activated during a single heartbeat or multiple heartbeats before a second combination is activated. In some embodiments, different combinations are configured for certain wavelengths of light that are slightly different, thus allowing the different combinations to be active simultaneously. 
     In some embodiments, only a subset of light sources  204  and photodetectors  202  might have adequate contact with the skin of the user to provide reliable measurements. The system can analyze the data for various combinations and determine which photodetector  202 (s) and/or light source  204 (s) have adequate contact with the skin. For example, the system can identify measurements that have sudden changes (e.g., indicating skin coming into and out of contact with the skin), low variance (e.g., indicating that the light coming in might be ambient light or light passing around the finger and not through the finger), etc. When reliable light source  204 (s) and/or photodetector  202 (s) are determined, unreliable light source  204 (s) and photodetector  202 (s) can be deactivated. This can help preserve power and limit the amount of unreliable data being collected. 
       FIG. 2C  illustrates how light sources  204  and photodetectors  202  can alternate locations as they are placed around the ring  104 . For example, one light source  204  can be placed closer to the fingertip while another light source  204  can be place further from the fingertip. This can enable various photodetector  202  and light source  204  combinations that have different light paths through the finger. For example, one light path might be largely obstructed by bone or fat whereas a light path close to the fingertip is less obstructed. Various combinations of photodetectors  202  and light sources  204  can be activated in sequence to determine an optimal light path or otherwise enhance the quality of received data. 
     The photodetector  202  can be offset from the light source  204  along an axis of the ring  104 . For example, if the ring  104  is wide enough, the light source  204  can be positioned closer to the fingertip (while the ring  104  is worn) while the photodetector  202  can be positioned further from the fingertip. In some embodiments, multiple rings  104  can be designed to be worn together. As shown in  FIG. 2D , in some such embodiments, one ring  104   b  can include a light source  204  while another ring  104   a  can include a photodetector  202 . This can increase the offset between the light source  204  can photodetector  202  which can be beneficial in obtaining a reading in some embodiments. 
     In some embodiments, a first ring 104   b  can include somewhat standardized light sources  204  and additional ring(s)  104   a  can include various photodetector(s)  202  or other sensors for various purposes. For example, a user can purchase a photodetector  202  ring  104  that is more sensitive at a higher cost than a photodetector  202  ring  104  that is less sensitive. Multiple photodetector  202  rings  104  can be stacked on a finger for different purposes. 
       FIG. 2E  illustrates how a ring  104  can include photodetectors  202  and/or light sources  204  that continue around the interior of the ring  104 . In some embodiments, the photodetectors  202  and light sources  204  can be independently addressed such that the ring  104  can activate various combinations of photodetectors  202  and light sources  204 . These combinations can be activated sequentially to provide a more complete sampling of the oxygen saturation of the user. For example, if there are twenty photodetectors  202  and twenty light sources  204  around the interior of the ring, a first photodetector  202  can be activated with an opposing light source  204  (e.g., on the opposite side of the ring) followed by a second photodetector  202  light source  204  combination, until all twenty opposing combinations are activated. In some embodiments, a light guide can enable light from a single light source to emit light at different parts of the ring  104 . Similarly, a light guide can direct light from different parts of the ring  104  to a single photodetector  202 . 
       FIG. 3  illustrates an example cross section of the ring  104  and finger  302 . A photodetector  202  can be placed on one part of the ring  104  while two light sources  204   a  and  204   b  can be placed on other parts of the ring  104 . The combination of the light source  204   a  and photodetector  202  can be used to capture absorption of the finger  204  along light path  304   a . The combination of light source  204   b  and photodetector  202  can be used to capture absorption of the finger  204  along light path  304   b . The system can compare the absorption detected for light paths  304   a  and  304   b  and determine which light path  304  provides more accurate information. For example, light path  304   a  might be occluded by a bone inside the finger  302  or light path  304   b  might have interference from light that travels through the surface of the skin or reflects between the skin and ring  104 . 
       FIG. 3  also illustrates how one light path  304   a  can largely be a transmissive light path  304  that passes through the finger whereas another light path  304   b  can be more reflective, relying on the reflection of the light within the finger. Because transmissive light paths  304  largely measure the absorption of the body and reflective light paths  304  largely measure the reflection of the body, a system can adjust the data accordingly. Data received can be tagged as transmissive data, reflective data, or a combination thereof. A system processing the data can incorporate this information. 
       FIGS. 4A-4D  illustrate example light techniques for controlling light according to various embodiments. In  FIG. 4A , the ring  104  is constructed with a hinge  402  and connection  404  whereby the ring can be tightened to a comfortable fit around the finger. Having a tight and comfortable fit allows the photodetector  202  and light source  204  to have better contact with the skin of the finger. The ring  104  in  FIG. 4A  can be adjustable. In some embodiments, the ring  104  is flexible and adjustable in size. In some embodiments, the connection  404  is an elastic element that pulls the two halves of the ring  104  together. Other clasping mechanisms are contemplated. 
     In  FIGS. 4B-4D , opaque light barriers  406  are shown on the ring  104  to minimize the amount of unwanted light by the photodetector  202 . For example, an opaque barrier  406  can encircle the photodetector  202  and can ensure that only light from the finger is received by the photodetector  202  and ambient light is blocked out as shown in  FIG. 4B . The opaque light barrier(s)  406  can be flexible so that they can form to the surface of the finger can create a close fit and prevent light leakage. An opaque barrier  406  can similarly encircle the light source  204  to block light that is not passed through the user&#39;s finger. As shown in  FIG. 4C , in some embodiments, such an opaque barrier  406  can be placed around the ring  104  on both sides (e.g., towards the fingertip and the side away from the fingertip) to create a tight seam between the ring  104  and the finger wherein little ambient light might interfere with readings of the photodetector  202 . As shown in  FIG. 4D , the opaque barrier  406  can be placed on the ring  104  in between the photodetector  202  and the light source  204  to prevent light leakage along the surfaces of the finger and ring. 
     The ring  104  can include elements to direct light from the light source  204 , through the finger, to the photodetector  202 . For example, the ring  104  can include a reflective material on parts of the ring&#39;s  104  interior to reflect some light back through the finger towards the photodetector  202 . This reflective material can be placed near the light source  204 . The ring  104  can include a dark material that absorbs light to minimize reflections around the surface of the finger. In some embodiments, the ring  104  includes a lens on or near the light source  204  and/or the photodetector  202  to better guide light paths through the finger. 
     The ring  104  can be rigid, flexible, or a combination of rigid and flexible. For example, the ring  104  can have a rigid area holding a printed circuit board with a flexible band completing the ring  104 . The flexible band can contain one or more photodetectors  202  and light sources  204 . The ring  104  can thus have a design similar to a miniature watch, but with functionality within the band. In some embodiments, components described herein can be affixed to standard or traditional rings  104 . 
       FIG. 5  illustrates an example organizational diagram for example components within a ring  104 . The ring  104  can include a processor  502  for analyzing data and preprocessing data before transmitting it to a portable electronic device. The processor  502  an also maintain and utilize security credentials for connecting to various networks and services. The ring  104  can include memory such as flash memory for storing data. The ring  104  can include communications circuitry for wireless and/or wired communications. For example, the ring  104  can use cellular networking, WiFi (e.g., 802.11x), Bluetooth, or other wireless protocols for communicating information to a smart watch, fitness band, cell phone, or other device. In some embodiments, the ring  104  can communicate to a user&#39;s phone using near field communication (NFC) while the user holds the phone. In some embodiments, the ring  104  can communicate to a smart watch which can relay information to a phone. For example, the ring  104  can communicate to a smart watch or fitness tracker using an ultra-low power wireless protocol and the smart watch/fitness tracker can then communicate the information to the user&#39;s phone using Bluetooth. 
     The ring  104  can include a battery or some other energy storage mechanism. In some embodiments, the ring  104  can store kinematic energy using a spring. In some embodiments, the battery is a capacitor that holds enough charge to operate the ring  104  for an extended period of time. The ring  104  can have an internal power source. For example, the ring  104  can have a battery and/or capacitor to hold energy. The ring  104  can be recharged periodically. For example, the user can place the ring  104  on an inductive charging stand. The ring  104  can have electrical contacts for receiving a charge. The ring  104  can receive energy from a nearby smart device such as a smart watch. This power can be communicated wirelessly. In some embodiments, a user&#39;s phone can be used to charge the device. For example, while a user holds their phone, it can be in close proximity to the ring  104  and can wirelessly charge the ring  104 . In some embodiments, the ring  104  can have a kinetic energy storage mechanism. For example, as the user moves their hand, a weight and spring can be used to store energy. 
     The ring  104  can have environmental sensors such as accelerometers  510 , barometers, magnetometers, gyroscopes, etc. The system can identify when the user is relatively still using these environmental sensors. This can help minimize the amount of data that is unusable because of noise caused by movement. In some embodiments, data from the environmental sensors can help adjust data from the photodetector(s) to account for motion. For example, if the system is measuring the pulse of the user, it can determine that variations of the data are largely caused by movement. 
     The ring  104  can present information to a user. For example, the ring  104  can include a display or LEDs directed outwards to indicate a status of the ring  104 . Such an LED can indicate a battery level for the ring  104 . A display can show the most recent oxygen saturation readings. The ring  104  can indicate wireless connectivity or lack thereof. The ring  104  can indicate if the user is overdue for a reading. This might occur if the user has been active and the user&#39;s finger has not been idle long enough for the ring  104  to obtain an accurate measurement. The ring  104  can indicate that it has new data for download to a portable electronic device and/or other system. This can help the user know that they need to connect the ring  104  or otherwise facilitate the download of information. In some embodiments, other feedback mechanisms can indicate a status of the ring. Such feedback mechanisms can supply gentle heat or electric pulse to the user or vibrational feedback. 
     A system can use this information to provide certain health data to a user and/or healthcare professional. For example, a user suffering from a sleep disorder such as sleep apnea can use the ring  104  to monitor their oxygen saturation throughout the evening. A system can use this data to detect menstrual patterns in a user, eating habits of the user, hydration of the user, and other vital signs of a user. The system can then present the user with a visual indication of this information. If the system detects an anomaly, it can alert the user or care provider. 
     The system can analyze data from the photodetectors to determine or predict various health parameters for the user or other interested an authorized parties. The user can see live data as to the user&#39;s current heart rate and oxygen saturation. If live data is not available (e.g., if the ring  104  only acquires or transmits data on a periodic basis) then the system can periodically display updates of the user&#39;s health information. In some embodiments, the system can provide feedback to the user about the user&#39;s health status. For example, the system can indicate that the user might not have slept well because of the user&#39;s SpO2 levels over the night. Because hemoglobin saturation and heart rate might change based on a woman&#39;s menstrual cycle, the system can inform the user about an upcoming event in their cycle (e.g., ovulation, start of menstruation, etc.). The ring  104  can detect lipids and/or glucose concentration in the user&#39;s blood and can monitor the user&#39;s diet patterns. This can be helpful for those with dietary conditions that should be monitored like diabetics. 
     The biometric data can be used within a hospital environment. For example, a patient can wear the ring  104  which can be monitored by hospital staff. The ring  104  can communicate directly to a hospital network using, for example, WiFi. In some embodiments, the system can determine if some threshold is reached and can alert medical personnel. For example, if the heart rate, blood saturation, or glucose measurements are outside of an expected or healthy range. 
       FIGS. 6A-6B  illustrate example techniques for retrieving data from the ring  104  according to various embodiments. The ring  104  can be configured to communicate wirelessly to other devices. While some wireless protocols have extensive range, such protocols generally consume more energy than low-range protocols. The ring  104  can have a longer battery life by using lower power wireless protocols to communicate information. In  FIG. 6A , the ring  104  can communicate to the portable electronic device  102  using near field communication (NFC). For example, the portable electronic device  102  can have an NFC antenna embedded in the back of the device and when it comes within proximity of the ring  104 , the ring can begin transmitting data to the portable electronic device  102 . In some embodiments, this NFC communication is powered completely by the portable electronic device  102  as would occur with “passive” NFC communications. For example, the portable electronic device  102  can charge a small capacitor in the ring  104  which can supply enough power to read data from a memory store on the ring  104  and transmit the data to the portable electronic device  102  using an NFC antenna. In some embodiments, the ring  104  is placed in a low power state until the portable electronic device  102  is within close proximity of the ring  104  based on the NFC connection. This technique can be useful because a natural position for holding the portable electronic device  102  might be such that the ring  104  is routinely located at an optimal position for NFC communication. Thus, downloads can happen without express user action. As the user uses their phone regularly, the phone can download information from the ring  102 . 
     In  FIG. 6B , a wrist device  602  can relay information from the ring  104  to the portable electronic device  102 . For example, the ring  104  can communicate information to the wrist device  602  over a first wireless protocol and the wrist device  602  can communicate the information to the portable electronic device  102  over a second wireless protocol. The two communications can be over the same wireless protocol but at different power levels. The wrist device  602  can be a smart watch, fitness tracker, or other device. 
     In some embodiments, raw data is transmitted from the ring  104 . This raw data can be processed at the wrist device  602  and/or the portable electronic device  102 . The processing can include filtering unreliable data or outlying data. The processing can include determining a pulse of the user, an oxygen saturation of the user, etc. In some embodiments, the ring  104  performs preprocessing of the data. Further processing can determine the health status of a user such as determining that the user has a sleep apnea. In some embodiments, data can be sent to a networked service which can further analyze the data and generate reports for display on the users portable electronic device  102 , ring  104 , wrist device  602 , etc. 
       FIG. 7  illustrates an example method  700  according to various embodiments. Measuring a person&#39;s blood oxygenation (SpO2) continuously in a form factor that they are willing to wear for long periods of time has been traditionally difficult. Continuous measurement overnight during sleep is needed to monitor for de-oxygenations related to sleep apnea. Traditional devices clip over the tip of the finger, or less commonly, attach to the ear or forehead. These traditional devices are uncomfortable, bulky, typically tethered, and otherwise unsuited for casual wear. These limitations hinder the functionality of the devices. Devices that are designed to be more user-friendly and/or comfortable typically make sacrifices in accuracy (e.g., by only using reflective observations). 
     The system can activate at least one light source on a ring  702 . There can be multiple light sources on the ring. With multiple light sources, the light sources can be of the same type or different types. Each light source can be a light emitting diode (LED) or other light source. Various light sources can be configured to emit different wavelengths of light, whether inherently or through the application of filters. The LEDs can emit light with red wavelengths as well as infrared wavelengths. These two wavelengths can be used because they are effective at highlighting the differences between oxygenated and deoxygenated blood. 
     The system can activate at least one photodetector on the ring  704 . There can be multiple photodetectors on the ring. The photodetector(s) can be configured for a single wavelength of light or a small band of wavelengths. In some embodiments, a photodetector can detect multiple wavelengths. A light filter can be placed on a photodetector to isolate certain wavelengths. 
     The system can determine light information by detecting light from the at least one light source and the at least one photodetector over at least two periods of time  706 . For example, the light information can be measured at a first time period and a second time period. Thus the light information can include multiple readings corresponding to multiple time periods. 
     In some embodiments, there are multiple combinations of light sources and photodetectors which can be used to measure different light paths. For example, a first combination can include a first photodetector and a first light source and a second combination can include a second photodetector and a second light source. In some embodiments, the light source-photodetector combinations are reversed such that a first combination includes a photodetector positioned on the bottom of the ring and a second combination includes a photodetector positioned on the top of the ring. These different combinations can capture different light paths though the finger (or other body part) of a user. In some embodiments, a combination has multiple light sources combined with a single photodetector and/or multiple photodetectors combined with a single light source. In some embodiments, a light source is included in multiple combinations. In some embodiments, a photodetector is included in multiple combinations. 
     The system can take measurements using different combinations sequentially. For example, the system can take a measurement using a first combination and then take a measurement using the second combination followed by a measurement of the first combination again. A single combination might be occluded and not provide good measurements. Further, a single combination might have interference from ambient light because elements have an imperfect connection to the finger. The system can take measurements from multiple combinations throughout a measurement period. In some embodiments, the system can determine which combinations can provide optimal measurements and then only take measurements from those combinations during the measurement period. 
     A combination can include elements opposite of each other. For example, a photodetector on one side of the ring and a light source on the other side of the ring. This can enable transmissive measurements of light passing through the finger. In this design, red and infrared light sources can be incident on the palmar (ventral) side of the finger, just below the first knuckle (where a ring is worn), and a detector can receive the transmitted light on the opposite, dorsal side of the finger. Thus the optical path from light source to detector extends through the finger from the palm side to the back side. This can provide a more accurate reading in comparison to reflective readings. In some embodiments, the photodetector and light source can be positioned close to each other to facilitate reflective measurements. Other combinations are contemplated such as a 90 degree offset such that the light source is placed at the top of the finger and the photodetector is placed on the right side of the finger. Other configurations are contemplated. 
     In some embodiments, the ring device is configured like a sleeve over the finger. Such a sleeve can expose the fingertip. The ring device can be flexible and malleable. Flexibility of the device can be facilitated by using a flexible printed circuit board. In some embodiments, multiple rings can be used along an axis of the finger. One ring can include a light source and another ring can have a light detector. In some embodiments, different rings can separately gather data. The data from the separate rings can be compared to determine what data represents biometric information and which represent motion data or noise. The multiple rings can be on different fingers. 
     The system can gather data and analyze it to determine various characteristics of a user&#39;s finger. For example, the system can measure the blood oxygenation (e.g., SpO2) of a user, the heartbeat of a user, and other characteristics. 
     The advantage over existing blood oxygenation measuring and sleep monitoring equipment is that it allows a system to use a site on the body (the finger ring position) that is more comfortable. This makes apnea screening less burdensome to the user and is less likely to disturb a user&#39;s sleep, while still maintaining high blood oxygenation accuracy and precision. Disturbing a user&#39;s sleep with uncomfortable devices is undesirable in sleep disorder screening, because the goal is to measure conditions as close as possible to the user&#39;s natural sleep habits. 
     A ring would also allow for general blood oxygenation monitoring throughout the day (e.g., for monitoring chronic conditions such as COPD) without obstructing a user&#39;s activities in a way a finger clip would. Other approaches rely on bulky and obtrusive devices. A ring is much less obtrusive to normal activities than this approach, and thus more suitable for all day monitoring. 
     In some embodiments, the system can take measurements of ambient light  707  (e.g., from the photodetectors with the light source(s) disabled). This can be used as a baseline for adjusting measurements of light from the light source(s). 
     The system can determine motion data using at least one motion detector on the ring  708 . For example, the system can have an accelerometer, gyroscope, compass, etc. for determining whether the device is in motion. In some embodiments, this motion data can be used to determine that the device is still and ready for measurement (e.g., that a user is sleeping). The system can use measurement data to cancel out motion effects in the data. For example, oscillations manifest in the data might be caused by movement and not the user&#39;s pulse. The system can attempt to remove these effects. 
     The system can determine biometric information using the light information and the motion data  710 . As described above, the system can use the motion data to determine periods of rest where measurements might be more reliable. The system can also use the motion data to cancel out motion effects in the data. The biometric information can be largely based on the absorption and transmission of wavelengths of light through the user&#39;s body. 
     The system can transmit the biometric information at the ring using a wireless protocol  712 . For example, the system can use near field communication (NFC), Bluetooth, WiFi, and other protocols. In some embodiments, the system only transmits data when the user holds a phone. The system can transmit the data to a wrist device, a portable electronic device, a networked system, etc. In some embodiments, the system can relay information between devices (e.g., first to a wrist device then to a portable electronic device). 
       FIG. 8  illustrates components an example system that can be utilized in accordance with various embodiments. In this example, the device includes at least one processor  802 , such as a central processing unit (CPU) or graphics processing unit (GPU) for executing instructions that can be stored in a memory device  804 , such as may include flash memory or DRAM, among other such options. As would be apparent to one of ordinary skill in the art, the device can include many types of memory, data storage, or computer-readable media, such as data storage for program instructions for execution by a processor. The same or separate storage can be used for images or data, a removable memory can be available for sharing information with other devices, and any number of communication approaches can be available for sharing with other devices. The device typically will include some type of display  806 , such as a touch screen, organic light emitting diode (OLED), or liquid crystal display (LCD), although devices might convey information via other means, such as through audio speakers or projectors. 
     A tracker or similar device will include at least one motion detection sensor, which as illustrated can include at least one I/O element  810  of the device. Such a sensor can determine and/or detect orientation and/or movement of the device. Such an element can include, for example, an accelerometer, inertial sensor, altimeter, or gyroscope operable to detect movement (e.g., rotational movement, angular displacement, tilt, position, orientation, motion along a non-linear path, etc.) of the device. An orientation determining element can also include an electronic or digital compass, which can indicate a direction (e.g., north or south) in which the device is determined to be pointing (e.g., with respect to a primary axis or other such aspect). A device may also include an I/O element  810  for determining a location of the device (or the user of the device). Such a positioning element can include or comprise a GPS or similar location-determining element(s) operable to determine relative coordinates for a position of the device. Positioning elements may include wireless access points, base stations, etc., that may either broadcast location information or enable triangulation of signals to determine the location of the device. Other positioning elements may include QR codes, barcodes, RFID tags, NFC tags, etc., that enable the device to detect and receive location information or identifiers that enable the device to obtain the location information (e.g., by mapping the identifiers to a corresponding location). Various embodiments can include one or more such elements in any appropriate combination. The I/O elements may also include one or more biometric sensors, optical sensors, barometric sensors (e.g., altimeter, etc.), and the like. 
     As mentioned above, some embodiments use the element(s) to track the location and/or motion of a user. Upon determining an initial position of a device (e.g., using GPS), the device of some embodiments may keep track of the location of the device by using the element(s), or in some instances, by using the orientation determining element(s) as mentioned above, or a combination thereof. As should be understood, the algorithms or mechanisms used for determining a position and/or orientation can depend at least in part upon the selection of elements available to the device. The example device also includes one or more wireless components  812  operable to communicate with one or more electronic devices within a communication range of the particular wireless channel. The wireless channel can be any appropriate channel used to enable devices to communicate wirelessly, such as Bluetooth, cellular, NFC, or Wi-Fi channels. It should be understood that the device can have one or more conventional wired communications connections as known in the art. The device also includes one or more power components  808 , such as may include a battery operable to be recharged through conventional plug-in approaches, or through other approaches such as capacitive charging through proximity with a power mat or other such device. In some embodiments the device can include at least one additional input/output device  810  able to receive conventional input from a user. This conventional input can include, for example, a push button, touch pad, touch screen, wheel, joystick, keyboard, mouse, keypad, or any other such device or element whereby a user can input a command to the device. These I/O devices could even be connected by a wireless infrared or Bluetooth or other link as well in some embodiments. Some devices also can include a microphone or other audio capture element that accepts voice or other audio commands. For example, a device might not include any buttons at all, but might be controlled only through a combination of visual and audio commands, such that a user can control the device without having to be in contact with the device. 
     As mentioned, many embodiments will include at least some combination of one or more emitters  816  and one or more detectors  818  for measuring data for one or more metrics of a human body, such as for a person wearing the tracker device. In some embodiments this may involve at least one imaging element, such as one or more cameras that are able to capture images of the surrounding environment and that are able to image a user, people, or objects in the vicinity of the device. The image capture element can include any appropriate technology, such as a CCD image capture element having a sufficient resolution, focal range, and viewable area to capture an image of the user when the user is operating the device. Methods for capturing images using a camera element with a computing device are well known in the art and will not be discussed herein in detail. It should be understood that image capture can be performed using a single image, multiple images, periodic imaging, continuous image capturing, image streaming, etc. Further, a device can include the ability to start and/or stop image capture, such as when receiving a command from a user, application, or other device. The example device includes emitters  816  and detectors  818  capable of being used for obtaining other biometric data, which can be used with example circuitry discussed herein. 
     If included, a display  806  may provide an interface for displaying data, such as HR, ECG data, blood oxygen saturation (e.g., SpO 2 ) levels, and other metrics of the user. In an embodiment, the device includes a wristband and the display is configured such that the display faces away from the outside of a user&#39;s wrist when the user wears the device. In other embodiments, the display may be omitted and data detected by the device may be transmitted using the wireless networking interface via near-field communication (NFC), Bluetooth, Wi-Fi, or other suitable wireless communication protocols over at least one network  820  to a host computer  822  for analysis, display, reporting, or other such use. 
     The memory  804  may comprise RAM, ROM, FLASH memory, or other non-transitory digital data storage, and may include a control program comprising sequences of instructions which, when loaded from the memory and executed using the processor  802 , cause the processor  802  to perform the functions that are described herein. The emitters  816  and detectors  818  may be coupled to a bus directly or indirectly using driver circuitry by which the processor  802  may drive the light emitters  816  and obtain signals from the light detectors  818 . The host computer  822  communicate with the wireless networking components  812  via one or more networks  820 , which may include one or more local area networks, wide area networks, and/or internetworks using any of terrestrial or satellite links. In some embodiments, the host computer  822  executes control programs and/or application programs that are configured to perform some of the functions described herein. 
     In various embodiments, approaches discussed herein may be performed by one or more of: firmware operating on a monitoring or tracker device or a secondary device, such as a mobile device paired to the monitoring device, a server, host computer, and the like. For example, the monitoring device may execute operations relating to generating signals that are uploaded or otherwise communicated to a server that performs operations for removing the motion components and creating a final estimate value for physiological metrics. Alternatively, the monitoring device may execute operations relating to generating the monitoring signals and removing the motion components to produce a final estimate value for physiological metrics local to the monitoring device. In this case, the final estimate may be uploaded or otherwise communicated to a server such as host computer that performs other operations using the value. 
     An example monitoring or tracker device can collect one or more types of physiological and/or environmental data from one or more sensor(s) and/or external devices and communicate or relay such information to other devices (e.g., host computer or another server), thus permitting the collected data to be viewed, for example, using a web browser or network-based application. For example, while being worn by the user, a tracker device may perform biometric monitoring via calculating and storing the user&#39;s step count using one or more sensor(s). The tracker device may transmit data representative of the user&#39;s step count to an account on a web service (e.g., www.fitbit.com), computer, mobile phone, and/or health station where the data may be stored, processed, and/or visualized by the user. The tracker device may measure or calculate other physiological metric(s) in addition to, or in place of, the user&#39;s step count. Such physiological metric(s) may include, but are not limited to: energy expenditure, e.g., calorie burn; floors climbed and/or descended; HR; heartbeat waveform; HR variability; HR recovery; respiration, SpO 2 , blood volume, blood glucose, skin moisture and skin pigmentation level, location and/or heading (e.g., via a GPS, global navigation satellite system (GLONASS), or a similar system); elevation; ambulatory speed and/or distance traveled; swimming lap count; swimming stroke type and count detected; bicycle distance and/or speed; blood glucose; skin conduction; skin and/or body temperature; muscle state measured via electromyography; brain activity as measured by electroencephalography; weight; body fat; caloric intake; nutritional intake from food; medication intake; sleep periods (e.g., clock time, sleep phases, sleep quality and/or duration); pH levels; hydration levels; respiration rate; and/or other physiological metrics. 
     An example tracker or monitoring device may also measure or calculate metrics related to the environment around the user (e.g., with one or more environmental sensor(s)), such as, for example, barometric pressure, weather conditions (e.g., temperature, humidity, pollen count, air quality, rain/snow conditions, wind speed), light exposure (e.g., ambient light, ultra-violet (UV) light exposure, time and/or duration spent in darkness), noise exposure, radiation exposure, and/or magnetic field. Furthermore, a tracker device (and/or the host computer and/or another server) may collect data from one or more sensors of the device, and may calculate metrics derived from such data. For example, a tracker device may calculate the user&#39;s stress or relaxation levels based on a combination of HR variability, skin conduction, noise pollution, and/or sleep quality. In another example, a tracker device may determine the efficacy of a medical intervention, for example, medication, based on a combination of data relating to medication intake, sleep, and/or activity. In yet another example, a tracker device may determine the efficacy of an allergy medication based on a combination of data relating to pollen levels, medication intake, sleep and/or activity. These examples are provided for illustration only and are not intended to be limiting or exhaustive. 
     An example monitoring device may include a computer-readable storage media reader, a communications device (e.g., a modem, a network card (wireless or wired), an infrared communication device) and working memory as described above. The computer-readable storage media reader can be connected with, or configured to receive, a computer-readable storage medium representing remote, local, fixed and/or removable storage devices as well as storage media for temporarily and/or more permanently containing, storing, transmitting and retrieving computer-readable information. A monitoring system and various devices also typically will include a number of software applications, modules, services or other elements located within at least one working memory device, including an operating system and application programs such as a client application or Web browser. It should be appreciated that alternate embodiments may have numerous variations from that described above. For example, customized hardware might also be used and/or particular elements might be implemented in hardware, software (including portable software, such as applets) or both. Further, connection to other computing devices such as network input/output devices may be employed. 
     Storage media and other non-transitory computer readable media for containing code, or portions of code, can include any appropriate media known or used in the art, such as but not limited to volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data, including RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices or any other medium which can be used to store the desired information and which can be accessed by a system device. Based on the disclosure and teachings provided herein, a person of ordinary skill in the art will appreciate other ways and/or methods to implement the various embodiments. 
     The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. It will, however, be evident that various modifications and changes may be made thereunto without departing from the broader spirit and scope of the invention as set forth in the claims.