Leveraging your Smartphone for “Man-Down” Detection Using Blueforce Tactical

For years, firefighters have leveraged PASS devices (Personal Alert Safety System) which are also referred to as distress signal unit (DSU) when going into building fires or other dangerous IDLH environments The PASS device sounds a loud (95 decibel) audible alert to notify others in the area that the firefighter is in distress, usually triggered by a lack of motion by the firefighter for a specific period of time (set by the National Fire Protection Association in NFPA 1982). The PASS device is normally used in conjunction with breathing apparatus and is usually a small, battery powered device attached to the self-contained breathing apparatus (SCBA) harness.

The age of the mobile device presents significant opportunity to leverage sensors native to every smartphone to deliver PASS capabilities without the airpack. Many different sensory devices can be used to determine the position and orientation of an object. The most common of these sensors are the gyroscope and the accelerometer. Though similar in purpose, they measure different things. When combined into a single device, they can create a very powerful array of information about a moving endpoint.

• A gyroscope is a device that uses Earth’s gravity to help determine orientation.
• An accelerometer is a device designed to measure non-gravitational acceleration. When the object it’s integrated into goes from a standstill to any velocity, the accelerometer is designed to respond to the vibrations associated with such movements.

Blueforce Tactical for Android and iOS now include the Blueforce PosiMotion software plugin. PosiMotion constantly monitors accelerometer and gyroscope sensors and reports motion and position as part of Blueforce presence. The plugin also includes user configurable settings that can detect a lack of motion as well as a “man down” using sensors as well as timers to warn the user, and others, when a lack of motion is detected. The plugin also reports bearing using the devices magnetometer. Bearing is reported with every Blueforce presence packet which is shared amongst subscribed endpoints and creates a real-time and historical “direction of travel” providing additional decision data for your deployed team.