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SOS

Activation modeTrackersUser Interface needed
Using a button (button press type, configured in button_mapping parameter)Micro Tracker, Smart BadgeButton
Compact trackerReed switch acting like a button
Using a downlinkAll-

This capability forces the device in a specific tracking mode tagged as SOS, for instance when the tracker's owner needs help.

Once this feature is activated, the behavior is the following:

  • The tracker sends a start SOS event payload.
  • The tracker continuously sends its position at a configurable period using sos_period parameter.
  • The tracker uses the geolocation strategy: geoloc_sensor.
  • The LoRaWAN™ position messages are tagged with an alert flag in the common header. (Refer to Common message header for more details)
  • The tracker's red LED is blinking.
  • The tracker plays a melody (if the bit 16 of the config_flags parameter is set).

The tracker can enter this mode by either the button sequence (see User Interface) or receiving a SOS start LoRaWAN™ downlink.

This mode is disabled by the same button sequence that triggered SoS start, or a SOS stop LoRaWAN™ downlink. When it is deactivated, a stop SOS event payload is sent, and the tracker stops blinking.

Refer to the Timing diagram section for more details about position messages scheduling.

Notes
  1. The button press(es) to activate the SOS is given in the parameter button_mapping.
  2. While the tracker is in SOS:
    • The operating mode reported in the payloads is the one before entering the SOS.
    • The alert bit is set. (Refer to Common message header for more details)
    • All downlinks are accepted except position on demand request and change the operating mode to OFF. With the following limitations:
      • The mode change requests are applied after leaving SOS
      • The parameter changes impacting the geolocation are applied at the next geolocation cycle
    • Between 2 button sequences, a delay of 20 seconds must be respected. If this delay is not respected the second sequence won't be considered.
    • During SoS, the LoRa duty cycle is deactivated
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