Design and experimental tests of a LoRaWAN based beacon system for cyclist with automatic crash detection

Cyclists are inherently vulnerable to unfortunate incidents like collisions with automobiles or solo accidents due to a defect or some other hazard on the road or trail. Despite the use of a helmet, the individual can suffer severe injuries that prevent him to call for help or maybe he lacks the means to do it. A proof of concept prototype for an emergency radio beacon focused on cyclists is presented, the system is intended to automatically detect an accident and send an alert to relatives, friends or emergency services including user's location in order to assist the person as soon as possible. Because of the crash detection mechanism implemented, where MEMS inertial sensors are distributed between the bicycle and the helmet, it is required two devices to be used, they keep BLE connection. The device attached to the bicycle also includes a GNSS receiver and a LoRa transceiver to send geolocation data over long distances until reach a gateway, then it is forwarded to the cloud to be processed and finally sent as an alert via SMS. An emergency signal is triggered only when specific motion events have been registered on both parts within a short time window. Additionally, given the capabilities of the bike device itself it is used as a tracker in case of theft. The experimental functional tests show that implementing distributed motion sensing elements for getting more information about involved objects kinematics, has a better response than those using only one, essentially because it is more effective to rule out false positives. LoRa technology allows implementation of small, energy efficient, long distance and bidirectional communicating devices for emergency alert related applications. On field tests the coverage of the entire urban area of the city of Cuenca was reached with a single active gateway, a maximum distance of 7.6km and a packet loss of 18%.