3D medical background with virus cells.

PocketCare S

Empower Social Distancing in the Workplace

Currently available for CSE students, faculty and staff as a pilot study for UB wide deployment, PocketCare S is a bluetooth low energy (BLE) solution which enables smartphones to send and receive anonymous beacon signals. It checks the distance between a smartphone and another beacon (or smartphone running PocketCare S) to see if they are close to each other (less than two meters). If so, the smartphone records the duration a close encounter with another beacon. PocketCare S is designed to report social distance information without collecting or revealing any personally identifiable information about any specific individual.

PocketCare S provides each user with the number of other users who have been in close proximity with the user on an hourly and daily basis, as well as  other relevant information at the workplace. It also reports to the user the duration of the close encounter sessions the user had, and alerts the user if the duration of the current session exceeded a certain threshold. 

An analytics dashboard will provide both app users and administrators with the social distance information aggregated from all users, such as the total number and duration of the close encounters in the workplace. Viewers will be able to see the number of app users who have had more (or less) than a given number of minutes of close encounters. This information is meant to empower both app users and administrators to practice and encourage good social distancing in the workplace.

By design, PocketCare S currently does not use the close encounter information to automatically notify app users of exposure to another app user who has tested positive with flu or viruses such as COVID-19. Instead, it provides the information to authorized health professionals to perform contact tracing.

PocketCare S is built upon another application, called PocketCare, developed five years ago by CSE faculty and students at the University at Buffalo to track flu/virus propagation through close contact, and used by many volunteers. The data collected has also been used to model and predict flu/virus propagation in a paper titled "PocketCare: Tracking the Flu with Mobile Phones Using Partial Observations of Proximity and Symptoms." PocketCare S is a second generation of PocketCare, where “S” also stands for “social distance.”

Disclaimers: (1). PocketCare S is intended to measure social distance on UB's campus although it may also be used for other SUNY campuses and other pre-defined premises; (2). Due to inherent limitations of the smartphone technology, PocketCare S does not guarantee that the information on the number, duration, or distance of the close encounters is accurate. The actual values may be above or below the estimated values; (3). PocketCare S provides links to other websites, which may or may not collect personally identifiable information, independent of PocketCare S.

On this page:


The Android version of PocketCare S is available on Google Play.

Due to Apple's restrictions, the iOS version is available only through Apple's Enterprise Developer Program and currently limited for use within UB. Please click the button below for instructions.

Get Updates

You can subscribe below to be notified by email of any update. Your email address will only be used for receiving notifications pertaining to PocketCare S and will not be used by the PocketCare S app when you download and install it on your phone.

Contact Us

Email the PocketCare S Development Team at ub-pocketcares@buffalo.edu

PocketCare S Videos and Diagram

PocketCare S - Empower Social Distancing in the Workplace

1) This video is based on the version submitted to IBM’s Call for Code Challenge 2020.

2) The version being deployed at UB differs slightly as follows:

a. the UB version does not ask users to enter any health information in the app. Instead, the app provides a link to UB’s main website for COVID-19, so users can use a separate chatbot to do daily health check; and

b. the UB version will not automatically alert users of exposures to other individuals who have been tested positive of COVID-19. Instead, the app will provide close contact information to authorized personnel, who will contact the exposed individuals.

PocketCare S Infographics

Clicking on the above infographic image will load a full size PDF version.

Clicking on the above infographic image will load a full size PDF version.

Data Collection, Usage, and Privacy Statement

To provide PocketCare S users (and administrators) information on the number (and duration) of close encounters, the app does not need and does not collect any private information about an individual person. Instead, each phone running the app generates a random name to be its virtual Bluetooth (VBT) name every hour, and then advertises this VBT name to other phones. Each phone, after collecting the VBT names of other close-by phones, displays the information on the number and duration of close encounters collected by itself on the phone, and also sends the information to the app server. The app server will aggregate the information from all users on campus, and make such aggregated information (instead of information about any particular individual) available to the analytics dashboard.   

It is worth noting that no other users will be able to predict the VBT name to be used by your phone and will therefore not be able to track you. In addition, the app server assigns another random number, to be referred to as App Client ID, to each instantiation of the app on a user’s phone, and this App Client ID cannot be used to identify a specific phone or individual.  In fact, the App Client ID changes every time a user re-installs the app.  Accordingly, neither other app users nor the app server will have any personally identifiable information.

To perform contact tracing, authorized personnel need to be able to identify app users. To meet such needs, a separate database is created as a result of authenticating each app user using UB’s Single Sign On (SSO). This separate database contains each app user’s UBITName (and email address), but no other personally identifiable information such as phone number or address. It can only be accessed by authorized personnel and is used for contact tracing purposes only.

The app requires the GPS to be turned on at all times in order (1) for the Bluetooth scanning to work, and (2) for geo-fencing to work (i,e, to determine if a close encounter with another beacon occurs on a campus or not). However, no GPS location information is stored on the phone or the server.  In particular, the GPS location information is used only for geo-fencing purposes: i.e., to identify if an app user is on campus or off campus, but not specifically where on campus or off-campus. In other words, the app does not track any individual whether on or off campus.

More information about how Pocketcare S works is provided below.

How it Works

Tips and General Info

Help you learn about and practice safe social distancing.

Close Encounter Data

Stats on the number and duration of close encounter sessions.

UB Webportal

Access the website for "COVID-19: UB Planning and Response"

Pocket Care S logo.

Only anonymous data (no personal data) is collected.


Required for discovering nearby beacon devices.


Required for beacon scanning but no location data is collected.


Frequently Asked Questions

Collected information and user privacy

  • What information does PocketCare S collect?

    PocketCare S collects the number and duration of close encounters between two smartphones (based on non personally identifiable information in the form of a randomly generated and dynamically changing virtual Bluetooth (or VBT) name of each phone.  As a part of the user authentication process via UB's Single Sign On (SSO), users' UBITNames will also be collected but this information is stored separately and is accessible by authorized personnel for contact tracing purposes only. The app will not ask users to enter any personally identifiable information such as your name, address or telephone number.
  • Where will the information collected by PocketCare S be stored and who will have access?

    All information collected will be stored on a secure server maintained by UB’s IT professionals (certified to manage more sensitive information than what this app will collect), and the information will only be accessible by authorized personnel. In particular, users’ UBITNames will be kept separately and used for contact tracing purposes only.
  • Can I be identified using the information collected?

    No other app users will be able to identify you based on the close encounter information (and the VBT name of your phone) collected by their phones. In addition, no one will be able to identify you based on the close encounter information (and the App Client IDs as well as the VBT names) collected by the server, except when a person is authorized to have access to the UBITName for contact tracing purposes.

Statistics provided by Pocketcare S

  • What information does PocketCare S provide to a user and administrators?

    PocketCare S reports statistics on users’ social distance, including the number and duration of close encounters an individual has on an hourly and daily basis. For both users and administrators, PocketCare S provides statistics  aggregated from all users, instead of any specific user, on the total number and duration of close encounters occurred while the users are in the workplace.
  • What does having “a close encounter” mean?

    A close encounter is a period of five minutes or longer during which two users were within two meters of one another. PocketCare S estimates the distance and duration of close proximity with another user. If PocketCare S determines that your smartphone is within two meters of another smartphone running PocketCare S for at least five minutes, then it considers that you had one close encounter (session). If PocketCare S determines that you are within two meters of another user but for less than five minutes (e.g. when you walk by another user), then it does not consider you had a close encounter.
  • How accurate is the distance estimation?

    Due to various factors affecting the strength of received Bluetooth radio signals, distance estimation will not be 100% accurate. PocketCare S makes a best effort to determine if the distance is above or below two meters.  Since this two meter distance is also somewhat arbitrarily defined, small errors in the distance estimation are also acceptable. PocketCare S uses advanced techniques to achieve the best-in-class accuracy in its information.
  • How accurate is the duration of a close encounter?

    As with distance, the accuracy of the duration estimation is affected by not only the distance estimation errors but also short naps (up to five minutes) taken by your smartphone to save battery power. PocketCare S uses advanced techniques to achieve the best-in-class accuracy in its information.

Contact Tracing and COVID-19

  • Will I be notified if I’ve had close contact with someone who has COVID-19?

    Not through PocketCare S. PocketCare S, by design, does not perform contact tracing automatically by sending push notifications to exposed users. It only reports close proximity information with another PocketCare S user and alerts an individual if the current close encounter session exceeds 10 minutes. PocketCare S does provide useful information to authorized personnel who will perform contact tracing based on the close encounter information provided by PocketCare S and the UBITNames obtained from the authentication process (via SSO) as mentioned earlier.
  • What should I do if I have flu/virus symptoms?

    Please follow established guidelines on reporting your symptoms and contact your health care provider.

Bluetooth and GPS

  • Will anyone be able to track the whereabouts of my phone if I turn on the Bluetooth and GPS as required by the app?

    No. Although authorized personnel with access to collected data know about the close encounters at the workplace, and no one can track the whereabouts of your phone. This is because PocketCare S uses a randomly generated and dynamically changing name (referred to as VBT) for your smartphone’s Bluetooth radio.  In addition, although GPS is required for the app to run, no GPS location information is collected by the app on the phone or by the server.
  • Other than the server for PocketCare S, will anyone else be able to extract any information or send me unsolicited information (or malware) through Bluetooth or the app?

    No. Since each smartphone running PocketCare S will only broadcast its VBT name (which is randomly generated and dynamically changing) for other smartphones to discover, and scans for such broadcast VBT names from other smartphones running PocketCare S only, no one else (whether they are PocketCare S users or not) can send or extract any other unsolicited information through the Bluetooth or the app.
  • How does my smartphone communicate with the server?

    Like most privacy-preserving apps, when you download PocketCare S, a unique and randomly generated App Client ID is associated with the app running on your phone. The server then uses this App Client ID to communicate with your phone. In the case of PocketCere S, the App Client ID allows the server to link two different VBT names so it can provide a summary information on the social distance for each app user. If needed, the server can also send you a “push notification” without knowing about the other specific information about your phone (e.g., the IMEI number, telephone number, or Wi-Fi/Bluetooth MAC address, etc.).
  • Can others use the App Client ID information mentioned above to identify me or send me unsolicited information or malware?

    No. Due to the anonymous nature of the App Client ID used, no one can identify which specific phone or user this randomly generated ID is associated with; not even the server.  In fact, after PocketCare S is uninstalled and reinstalled, a different App Client ID will be associated with the phone. 
  • How does PocketCare S measure distance?

    PocketCare S uses your smartphone’s Bluetooth radio to receive special beacon signals sent by other smartphones running PocketCare S, and uses the received signal strength and a special formula to estimate the distance.
  • How frequently does PocketCare S measure distance?

    PocketCare S typically scans every minute and can work 24/7, but in order to save battery, your smartphone may wait up to five minutes before taking the next measure.
  • Will PocketCare S drain a lot of battery power?

    PocketCare S uses Bluetooth Low Energy and is designed to operate 24/7 without any significant drain on your battery.

Contact Us

If you have questions or comments about the PocketCare S app, email ub-pocketcares@buffalo.edu. Your feedback is appreciated.

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