Accident Detection System

Project Overview

This project is a real-time accident detection and alert system designed for vehicle safety. It utilizes the MPU6050 motion sensor to detect unusual acceleration or impacts that might indicate a crash. Upon detection, it fetches the GPS location using the A9G module and sends an SMS alert with location data to predefined emergency contacts.

How It Works

• Motion Detection: The MPU6050 continuously monitors acceleration and gyroscopic values. When the resultant force magnitude crosses a predefined threshold, it flags a possible accident.
• GPS Location Fetching: After motion is flagged, the A9G module is activated to fetch precise latitude and longitude using AT+LOCATION=2.
• Alert Sending: Using A9G's GSM capabilities, the system sends an SMS containing the GPS coordinates and a short alert message to a predefined phone number.
• Emergency Calling: In critical mode, it can also initiate a voice call to the same number using the ATD+91XXXXXXXXXX; command.
• Failsafe: The system retries in case GPS fails to lock or if the message sending fails initially.

Code Overview

📡 Code 1: A9G GPS Finder

Purpose: To validate GPS functionality and fetch real-time location data from the A9G module using AT+LOCATION=2.

// Initialize UART
Serial1.begin(115200);

// Enable GPS
Serial1.println("AT+GPS=1");

// Request location repeatedly
Serial1.println("AT+LOCATION=2");

• Initializes UART communication via Serial1
• Sends AT+GPS=1 to enable GPS tracking
• Requests GPS data using AT+LOCATION=2
• Displays raw GPS output on Serial Monitor for debugging

Use Case: Standalone script to test GPS signal lock before deploying in main code.

📶 Code 2: A9G GSM Test & SMS Sender

Purpose: To test SIM communication, send SMS, and place calls through the A9G module.

// Set SMS to text mode
Serial1.println("AT+CMGF=1");

// Send test SMS
Serial1.print("AT+CMGS=\"+91XXXXXXXXXX\"\r");
Serial1.print("Hi Test Message From Ai Thinker A9 Module");
Serial1.write(0x1A); // End message (CTRL+Z)

// Make a call
Serial1.print("ATD+91XXXXXXXXXX;\r");

• Sends a test SMS: Hi Test Message From Ai Thinker A9 Module
• Deletes previous SIM messages using AT+CMGD=4,4
• Places a call with ATD+91XXXXXXXXXX;
• Configures text mode AT+CMGF=1 and SIM storage with AT+CPMS
• Includes a Reply() function for sending dynamic texts
• Uses UpdateSerial() to mirror Serial1 output for debugging

Use Case: Verify GSM-side functionality — calling, texting, and SIM readiness before full integration.

Tech Stack