Project / Embedded systems
A low-cost, portable responder-and-control system that transmits GPS location, motion data, and SOS alerts over LoRa for disaster-response scenarios.
STM32LoRaGPSMPU-6050
Built during the BIOMISA Research and Innovation Student Lab internship, the device was designed to make search-and-rescue monitoring more accessible. A responder unit collects location and motion data, while a separate control unit receives and displays the live packet stream.
The responder STM32 reads the NEO-6M GPS and MPU-6050, then transmits the data through an SX1278 LoRa radio. An SOS button interrupts the sleep cycle and triggers an urgent transmission window. At the other end, a second STM32 decodes the packets and presents the information on a 20×4 I2C LCD with an audible buzzer.
Firmware was developed and flashed with STM32CubeIDE and STM32CubeProgrammer. GPS data was cross-checked against Google Maps, while LoRa range and packet size were tested iteratively to balance reliability and payload capacity. Sleep-mode operation reduced average current from 110.7 mA to 72.9 mA, increasing the estimated 2000 mAh battery runtime from 27 to 41 hours.
LCD refresh glitches were corrected through improved update logic; GPS acquisition was improved with open-area testing and retry handling. The working prototype was mounted on a test dummy and evaluated in simulated disaster environments, demonstrating real-time coordinates, motion status, and SOS alerts for faster rescue decisions.
