Bluetooth App Insights from VMWare Pivotal Labs

VMware Pivotal Labs recently released Herald open source contact tracing for iOS and Android. Pivotal Labs was previously awarded three contracts worth £4.8m to develop a contact tracing app for the United Kingdom only for it to be abandoned for a new app based on the Google/Apple contact tracing mechanism.

Herald can’t be used for contact tracing unless you are a government agency because 3rd parties can’t publish such apps on the Apple app store. However, Pivotal Lab’s deep work in this area provides many insights into the use of Bluetooth on smartphones. The library itself also has other uses other than contact tracing:

  • Communication apps
  • File sharing between Android and iOS devices, reliably
  • Local ‘same location’ peer to peer applications, such as instant messaging or gaming apps
  • Safety apps
  • Using beacons in high-risk areas, an employee exposure app could accurate record exact exposure to hazardous environments
  • Also using beacons, know where to deep clean if an employee does fall ill at your large campus
  • Check in app – Walk around and be let in to secure areas automatically
  • Rescue app – e.g. for skiing/snowboarding avalanche rescue – find the hidden/non visible person. Could be fire in a large building, or rescue on a tube train

The documentation provides some useful information on technology approaches and OS specific issues.

Some insights:

  • Using scanning for 1-3 seconds with a gap of a few seconds between scanning uses 6-11% battery over 8 hours
  • Android phones’ speed when reading characteristics is significantly slower than write and acknowledge. Using write instead of read reduces the mean window times from above 8 seconds (minutes for some phones) to 0.5 – 4 seconds, depending on the handset. Use write characteristics wherever possible, and cache data to remove any redundant reads.
  • Apple iOS has a bug with background Bluetooth advertising where applications on two backgrounded iOS devices are not notified about each other. Two backgrounded iPhones cannot detect one other.
  • The background timer on Android sometimes gets stuck and might not wake for many minutes.
  • The way smartphones interpret Bluetooth signals to determine RSSI varies across Bluetooth chipsets. Some such as the iPhone 7 use a log approach while others use an inverse distance-squared scale. This affects accuracy if you subsequently use a common formula to derive distance from RSSI.

Read about Beacons for Workplace Social Distancing and Contact Tracing

Social Distancing Bluetooth RSSI Calibration

We previously described how social distance beacons differ from ordinary beacons. Devices advertise AND scan rather than just advertise OR scan. The principle is the same with with smartphones using the Apple/Google Exposure Notification API.

The problem with smartphones is that their transmit and receive capabilities vary widely. The received signal strength (RSSI) is inconsistent across types of smartphone and you can’t determine distance reliably. Apple and Google have mitigated this problem by attempting to create a database of calibration values (csv).

The calibration data is useful for Bluetooth developers creating solutions across devices. However, it’s of no use for 3rd party contact tracing as only Government agencies can use the Exposure Notification API and Apple is banning Covid related apps.

Our Social Distancing, Contact Alert, Track & Trace (CATT) Solution and social distancing beacons solve the calibration problem by only using one type of device.

Read about Beacons for Workplace Social Distancing and Contact Tracing.

Social Distancing Technologies Take the Fast Track Through the Hype Cycle

Gartner has a recent update to their research of hype cycles that takes into account disruption caused by the Covid pandemic.

Social Distancing Technology Hype Cycle

Five emerging trends have been identified:

  • Social Distancing Technologies
  • Composable Enterprise
  • AI-Assisted Design
  • Differential Privacy
  • Biodegradable Sensors

Social distancing technologies, related to the COVID-19 pandemic, are taking the fast track through the Hype Cycle and have high impact. Technologies rarely enter the Hype Cycle at the point where social distancing technologies has entered it

Social Distancing Tech

Our social distancing technology provides wearables that flash and make a sound when people come close together. We also have a system that collects and reports close contacts.

Wearable devices provide more reliable performance than smartphone apps because smartphones’ transmit and receive capabilities vary considerably across types of device. Using defined, known wristbands or lanyard devices eliminate the variances.

Read about Beacons for Workplace Social Distancing and Contact Tracing

Read about CATT Social Distancing System

England’s Contact Tracing App Now Trying the Apple/Google API

After wasting a lot of money and more importantly time, England has abandoned using the public mobile OS Bluetooth APIs and is now using Apple/Google’s new contact tracing APIs. However, all has not been wasted because the home grown solution included advanced processing of Bluetooth RSSI values that provided for more precise measuring of close contacts.

The problem now is that the Google/Apple solution doesn’t provide access to RSSI and instead makes its own determination of close contact. Developers are forced down the path of a closed solution that can’t be improved upon. The new app is worse at determining distance than the original NHS Covid-19 app:

Engineers are still trying to reduce how often the Bluetooth-based tech wrongly flags people as being within 2m (6.6ft) of each other

RSSI is very noisy due to radio multi-path distortion, reflection, shadowing and fading. It also varies due to differences across devices in transmit and receive capabilities.

Variation of RSSI in devices and due to the environment

We have previously mentioned the use of Kalman filtering to improve the processing of RSSI. A newer research paper by The Alan Turing Institute of University of Oxford Inferring proximity from Bluetooth Low Energy RSSI with Unscented Kalman Smoothers describes the processing of RSSI to infer close contacts. The BBC believes this is what was used in the older NHS app.

The paper shows show how good prediction of proximity and risk can be obtained by using RSSI sequences rather than applying thresholds to single values. This correlates with our findings in that our Bluetooth contact tracing solution uses sequences rather than value thresholds. The paper also mentions that the duration of the risk also makes some close contacts more important to classify correctly. Again, we concur in that our solution has the ability to contact trace based on contact duration.

England’s contact tracing is now heading in a better direction and in the direction we previously advocated. They now need to persuade Apple and Google to improve their solution.

How Much is Your Privacy Worth? Peoples’ Lives?

As Covid-19 rampages across the US, it’s noticeable that Apple and Google’s contact tracing tech is barely used in the United States. Here in the UK we are also in the top league for deaths as a proportion of population size. The Government has spent at least £11.8m developing an app that’s yet to be released and is reported will be downgraded to a risk rating app.

What happened? It was clear to us as far back as April that there were technical limitations of using public Bluetooth APIs for contact-tracing. Only the Google/Apple approach had a chance of working.

Apart from the UK’s technical mis-management, £11.8m is an extreme amount to spend on an app. Apps tend to cost thousands of pounds and in the extreme case hundreds of thousands. Yes, the solution needed a large and resilient server side. It still didn’t warrant anywhere near such a large spend. The panic buying of a solution can be the only explanation of such an incredible waste of money.

There are too sides to why there’s not been much take up of the Google/Apple solution. On the one hand Apple and Google want to protect end users’ privacy. In our opinion, iOS and Android had already gone too far down the protection and power savings paths. Daily, we see people struggling to get apps working due to protections and settings they don’t understand. People disable permissions thinking they are helping protect themselves but all they get is frustration when apps don’t subsequently work. Crippled background Bluetooth is a consequence of these over-zealous restrictions.

On the other hand, governments wanted to do more than the Google/Apple solution provided and collect more personal data. Google and Apple’s ‘our way is the only way’ created an impasse which means the majority of smartphones won’t be used, for the common good, to help save lives. It’s a combination of incompetence from one side and intransigence from the other. Is app privacy more important than peoples’ lives?

Read about Beacons for Workplace Social Distancing and Contact Tracing

Effects of Obstructions on the Accuracy of Bluetooth Contact Tracing

David Labrique1, an independent researcher, has a new paper on the Effects of Obstructions on the Accuracy of Bluetooth Contact Tracing.

Bluetooth Contact Tracing

He looks into the variation of Bluetooth received signal strength (RSSI) due to different types of obstruction such as walls and the human body. He explains how RSSI is being used in contact tracing apps and asks whether it’s possible to have false positives when there’s wall between smartphones or false negatives when people are close together but blocked by their bodies.

David used a Raspberry Pi as a Bluetooth emitter and a smartphone as a receiver, situated 1 metre apart and placed various obstacles between them. He found that drywall and stud walls were ineffective at reducing Bluetooth signal strength. Conversely, human bodies drastically reduce Bluetooth signals.

He concludes:

Smart watches might be possible candidates for more accurate contact tracing as they are less obstructed by the body when worn on the wrist

It’s well known that human bodies block Bluetooth. We have an article that explains how this phenomenon can even be used to infer direction.

What David didn’t do was test at different levels of power output. We assume he just used full power which will go through walls. Solutions such as our CATT use lower power predominantly to save battery life but also because there’s no need to transmit further. There’s are also factors at play in a smartphone app such as the variance of signal power across transmitting smartphone, the variance in the ability of different smartphones to receive the signal and the ability (or not) of smartphones to be able to transmit and receive in background when the app isn’t showing/running. These factors make app based contact tracing even more unreliable. Stand alone devices, such as smart watches mentioned by David, work better.

Read about CATT Social Distancing Solution

Social Distancing Beacons

Bluetooth Beacons getting COVID-19 Impacted Business Back on Track

It has been an enormously challenging time for so many organisations during the COVID-19 lockdown. Many are now scrambling to implement new measures within their business to help safeguard workers health and avoid further disruption and shutdowns.

With Governments worldwide issuing and updating guidance on a regular basis, many businesses are turning to technology experts for practical easy to implement solutions in the longer term fight against the virus.

In recent years, Bluetooth Beacon technologies have been gaining ground in many industries, with the global Beacon Technology market projected to reach USD 1249 million by 2026, at a CAGR of 25.8% during 2021-2026. The technology, in its simplicity, can be deployed in numerous and varied business applications, most recently in supporting social distancing and other compliance measures.

Here, we learn how Bluetooth Beacon technologies, such as BeaconZone CATT, are being deployed to safeguard the health and wellbeing of both employees and customers, and can help get your business back on track.

The Challenge


All employers have a duty of care to ensure their workplace is safe for workers to return to, by mitigating risks and implementing Government issued COVID-19 guidance.
Each business will encounter its own challenges in meeting both current requirements and potential needs for renewed restrictions and lockdowns, dependent on business environments, employee numbers, industry and activities. This requires, in many instances, huge shifts in business thinking, models and processes.

There is no doubt that being flexible and open to new ways of working will help make such changes more successful. As well as stringent cleaning and hygiene measures, social distancing is perhaps the biggest challenge, requiring behavioural as well as practical changes and consideration across all aspects of your business.

Installing screens and barriers to physically separate people has its merits but is not, in many circumstances practical, which is why many employers and organisations are turning to alert, track and trace technologies for help.

As well as the extensive guides provided by Government, The UK’s Chartered Institute of Personnel and Development (CPID) have several useful tools and detailed guidance to help support your returning to workplace needs.

Bluetooth Beacons to the Rescue

Bluetooth beacon technologies, already widely used in many business applications, from logistics and asset management to location-based gaming, marketing and events management, temperature and humidity monitoring and many more, are a game changer in supporting businesses in their fight against COVID-19, including:

  • Social Distancing:  Standalone social distancing devices and tracking systems,  such as BeaconZone CATT, provide an easy to implement and practical solution to help and remind your workers to retain social distancing with a range of wearables, including wristbands and lanyards that flash and vibrate when social distancing is infringed. Data collected and synced through management stations empower your managers to effectively monitor, report and resolve repeated infringements and manage and mitigate further risks and non-compliance.
  • Staff Locating:  Systems such as BeaconRTLS™, previously mainly used in factories and warehouses, are now being used more in COVID-19 Risk Assessments to determine the location of staff and occupancy of buildings. What might have seemed to be an invasion of privacy is now seen as something desirable to help ensure the safety of workers and audit compliance to government and industry-specific guidelines.
  • Lone Working: There has been an increase in the use of beacons providing touch-free ‘check-in’ for workers and for SOS. This includes use of gateways to automatically know when a worker has been at a specific locations, full locating systems and control centre systems such as TRBOnet. These systems allow a button to be pressed by the worker when, for example, there’s a medical emergency, threat to life or in customer facing scenarios, a potentially abusive situation. Such systems assist in complying with government lone worker regulations as well as provide peace of mind for both the employee as well as the employer.
  • Process Change:  As many businesses are reviewing and implementing new processes to safeguard the safety of their workers and customers, finding ways to make these more onerous tasks more efficient will be critical to business success. A great example is the huge challenges the hospitality industry is facing with cafes and restaurants increasingly adopting beacon technology to identify tables for use in app-based ordering of food.

Benefits of Beacons

Beacon CATT is a standalone Bluetooth solution which can be easily deployed and is scalable for your business. It has been designed to be a one-off investment and requires no additional hardware or WiFi, Ethernet or cellular connection. You can be assured that performance is reliable and data is secured within your own business with ongoing support and help form our expert advisors.

Our solutions are increasing in demand and helping organisations get back to business post COVID-19 lockdown, including:

  • Enhancing protection against COVID-19
  • Giving workers confidence in workplace safety
  • Restoring business productivity and continuity
  • Being agile to changing compliance needs
  • Reducing breaches and chance of shutdowns

Tasked with securing social distancing measures within your organisation? Learn more and try our Evaluation Starter Kit NOW!

Social Distance Wristbands Help Keep Sites Operating

As offices and sites re-open and people go back to work, it’s necessary to introduce social distancing measures in the workplace. We are hearing of factories being shut down after site-specific infection. Poor social distancing measures ultimately jeopardises the continuity of work in your organisation.

No matter what measures you put in place there will be some workers who flout the guidelines and others who are so engrossed in work that they forget about social distancing.

Social distance wristbands and lanyard wearable devices remind workers to maintain social distancing. Complete solutions allow close contact events to be taken off the distance wristband each day to audit compliance and if necessary, perform contact tracing.

Read about Social Distance Wristbands for Workplace Social Distancing and Contact Tracing

Restaurant of the Future

With restaurants and pubs here in the UK scrambling to reopen this weekend, they need to find ways to provide self-service and minimise contact with staff. It’s interesting to see what was considered a ‘future restaurant’ in 2014 makes much more sense today:

The concept restaurant at Eggcellent in Tokyo used iBeacons for the location aspects together with smartglasses, augmented reality and gesture interfaces. An Engadget article covered the restaurant in more detail.

Read about Using Beacons in Hospitality

Read about social distance wristbands

UK NHS Covid-19 Contact Tracking Source Code Available

The UK NHS has just released the Android and iOS source code for the UK NHS Covid-19 contact tracking app. This is the code used before the recent switch to the Google/Apple mechanism.

The iOS readme explains how it works:

Our unique identifier is also known as our service characteristic. In the Bluetooth spec, devices can broadcast the availability of services. Each service can have multiple characteristics. We use a characteristic to uniquely identify our service and distinguish from all other sorts of Bluetooth devices. For every device we find with a matching characteristic, we record an identifier for the device we saw, the timestamp, and the RSSI of the Bluetooth signal, which will allow a team later on to determine who was in close proximity to individuals infected with the novel coronavirus

Read about social distance bands