Category: ContactTracing

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

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

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

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

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

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

Just under a month ago we wrote about Bluetooth RSSI, Social Distancing and Contact Tracing and how the UK Government was going their own way:

Google and Apple have implemented a new API to allow contact tracing apps to work well on iOS and Android. Some Governments, such as ours in the UK, have currently gone their own way with apps that use existing APIs. Such aforementioned restrictions stop smartphones seeing each other thus severely reducing their effectiveness. The apps won’t work properly and will provide very limited benefit.

We are not surprised that Sky News is reporting that there has now been a U-turn.

To all governments trying to use the standard iOS and Android APIs to measure social distancing and perform contact tracing: You are wasting important time.

Read about Beacons for Workplace Social Distancing and Contact Tracing

We have had people ask how social distancing beacons such as distance bands differ to ordinary beacons. Normally, beacons send out (called advertising) Bluetooth signals that are received (called scanning) by apps on smartphones or Bluetooth gateways:

There’s no actual connection taking place. One side is repeatedly sending while the other is listening.

For social distancing, the beacons advertise AND scan:

Each beacon is repeatedly sending out an id and listening for others. Again, no connection takes place. When beacon receives scan data, it also sees the signal strength which can be used to infer the distance and hence whether the remote beacon is within the social distancing distance.

Beacons can store the id, signal strength and time. This can be extracted later via connection from another device such as a smartphone or gateway.

Read about Beacons for Workplace Social Distancing and Contact Tracing