Accident Detection SMS Alert System

I’m building a small embedded prototype that can recognise a road accident the instant it happens, trigger a buzzer on-board and then text the vehicle’s GPS coordinates to a presaved emergency contact. An accelerometer will be the sole crash-detection sensor, so the firmware has to watch for abnormal spikes on that device, classify them reliably as a collision rather than rough driving, and fire the alert routine. Here is the workflow I have in mind: the microcontroller samples the accelerometer, confirms the threshold breach, sounds the buzzer for nearby help, fetches latitude and longitude from an attached GPS module and immediately sends an SMS through a GSM or LTE-M modem. If the cellular network is down, the code should queue and retry until a signal is regained. What I need from you is a complete, working proof of concept—schematic, component list, well-commented source code (Arduino, ESP32, STM32 or a platform you recommend), plus a brief guide so I can replicate the setup on my bench and later move it to a custom PCB. Your detailed project proposal should explain the hardware stack you prefer, the crash-detection algorithm you’ll implement, and the best way to minimise false positives during sharp braking or potholes. If you’ve tackled anything similar—vehicle telematics, IoT safety devices, or SMS-based alerting—please weave that into the proposal so I can gauge fit. Looking forward to seeing how you would bring this life-saving idea from concept to a robust demonstration.