Bluetooth usage that could help in disaster situations

I read a tweet about communication protocols that could be used in a disaster. Then I asked myself how existing technologies could help.

As a disclaimer, I’m not a first responder or a disaster expert of any kind. Just an engineer trying to propose ideas to help.

Many Bluetooth tracker devices broadcast their information for days, even years. These trackers can be keychains, wristbands, or watches. Some publicly advertise their data in a way that can be interpreted easily.

In an earthquake situation, first responders could use Bluetooth scanners to detect if there are devices nearby and identify personal devices among them.

Thanks to the received signal strength indicator (RSSI), they can have a rough idea of the distance and get closer to the device.

Here is a screenshot from the free nRF Connect app while scanning for Bluetooth devices in the neighborhood:

You can see that the smartphone discovered a personal fitness tracker and gives an idea of the distance through the signal strength (-51 dBm, which is quite close).

Several apps propose to find Bluetooth devices with a localization view like the one below, helping identify and get closer to a device.

Device browser of the Theengs App

Furthermore, some of these devices broadcast data such as the person’s heart rate or steps, which could give meaningful information to first responders.

We could also imagine that an emergency mode of a personal tracker could trigger a broadcast of more data, like the person’s GPS location, or make encrypted data easily accessible.

One would say that the range of Bluetooth transmissions does not fit such use cases. The examples above are extracts from already available applications without any optimization for this usage. We could imagine using a directional antenna on the receiver side and dedicated software to process and analyze the data.

Finally, the person’s smartphone could be detected, as cleverly detailed in this study.

If you are interested or have any questions about this approach, feel free to message me.