One button. Five minutes. A life.
Here is exactly what happens between pressing the SOS button and your family receiving the text message.
From press to text message
Three steps separate the gesture from the alert arriving. The first two will happen inside the beacon; the third is already tested end to end.
Press on the SOS button
Even in deep sleep, the beacon will have to wake immediately and acquire the position. The design target is 3 to 5 metres in ideal conditions, with a first fix in under 30 seconds under open sky. Neither figure has been measured.
Satellite transmission
The Iridium modem sends an extremely compact message to a satellite in low earth orbit, with no need for any ground relay antenna.
Reception and text alert
Our server receives the frame and automatically sends a text message with your exact position to the emergency contacts you have saved.
Design targets
Values the design aims for. None has yet been measured on a prototype.
What the beacon will have to do
Four design choices. Not one has been proven on hardware yet.
No network required
The Iridium low-earth-orbit network covers the whole globe, the Tibesti included. The beacon will rely on it: that link is designed but has never been proven.
Long-lasting battery
LiFePO4 chemistry chosen for its stability at high temperature, with several weeks of standby as the target. Recharging planned by universal USB-C or portable solar panel.
Two-way
The Iridium SBD protocol chosen allows a downlink, from the server back to the beacon: a green LED would confirm the alert was received, and rescuers could signal their arrival. That return path is not implemented yet and has never run on hardware.
Made for Chad
Bilingual French and Arabic interface, enclosure targeting IP67, resistant to sand and knocks, designed for the local market.