luciobaiocchi/heard

HEARD (Hiking Emergency Assistance and Rescue Device) is an embedded system project for keeping hiking groups safe in areas with no phone signal. Each hiker carries a small device with a GPS chip and a LoRa radio, which is a long-range, low-power wireless technology that works without any cellular or internet infrastructure. The devices talk to each other directly, forming a mesh so that the group leader can see where everyone is in real time. The system works around a planned route loaded onto each device as a GPX file. A continuous check compares each hiker's position against a corridor around that route, defaulting to plus or minus 100 meters, and marks them as either on-path or off-path. The group leader's device, called the Core, periodically polls the rest of the group for their positions. If a hiker is too far for a direct radio connection, other devices in the group relay the message, passing it along hop by hop. Three simple message types handle the whole protocol: a broadcast request from the Core, a relay acknowledgment from intermediate devices, and a position reply that can carry aggregated location data. The prototype hardware is an ESP32 microcontroller paired with a GPS module, a LoRa transceiver, and a small e-ink display showing the group status. Field tests reported roughly one meter of GPS accuracy, a radio range of about three kilometers in open terrain, and around 300 to 400 meters in obstructed areas. Alongside the firmware, the repository includes a full software simulator. The actual protocol code from the firmware is compiled into a Python module so that simulated hiking runs can execute the real firmware logic rather than a reimplementation. The simulator models a probabilistic radio channel with optional terrain obstruction using real elevation data. Recorded simulation runs can then be replayed in a 3D browser viewer built with MapLibre, showing device positions, radio transmissions, and protocol state on actual terrain. This is a Bachelor's thesis project from the University of Bologna. The README notes that the standalone Node firmware build is not yet finished and that the project is not a certified safety device. It is licensed under Apache 2.0.