Smart-helmet-SOS

A hardware-based impact detection and emergency alert system using MPU6050 and a buzzer for real-time rider safety.

• Microcontroller: ESP32 (Dual-core, built-in Wi-Fi/Bluetooth)
• Sensor: MPU6050 (6-axis Accelerometer + Gyroscope)
• Alert: High-Decibel Buzzer

The complete circuit schematic for this project has been designed using KiCad and is available as a high-resolution vector PDF in the documentation folder.

🔗 Click here to view the Full Project Schematic (PDF)

For quick reference, the core system wiring is mapped as follows:

• MPU6050 Accelerometer: SDA $\rightarrow$ GP21, SCL $\rightarrow$ GP22 (I2C Bus)
• Crash Cancel Button: Input $\rightarrow$ GP13 (Configured with Internal Pull-Up)
• SOS Alarm Buzzer: Output $\rightarrow$ GP27 (Drives the 2N2222 Transistor Base)

The project creates a seamless bridge between local hardware sensors and mobile automation to send real-time coordinates during an emergency. The complete sequence flows horizontally as follows:

[ MPU6050 Acceleration Spike ] ──► [ ESP32-S3 Verification (10s Window) ] ──► [ Bluetooth Send: "ALARM_TRIGGER" ] ──► [ MacroDroid Automation Intercept ] ──► [ Mobile GPS Link Sent via SMS ]

1. Sensor Trigger: The MPU6050 continuous tracking algorithms detect a sudden deceleration or impact spike exceeding the programmed 22.0 m/s2 threshold.
2. Local Pre-Alert & Grace Period: The ESP32-S3 sounds a local alert through the transistor-driven active buzzer. This starts a 10-second countdown, allowing the rider to press the physical Cancel Button (GP13) if it is a false alarm.
3. Bluetooth Transmission: If the countdown expires without user cancellation, the ESP32-S3 establishes a connection to the paired smartphone via onboard Bluetooth Serial and transmits the string: ALARM_TRIGGER.
4. MacroDroid Interception: A background MacroDroid automation macro running on the Android device actively monitors the incoming Bluetooth Serial text log buffer.
5. GPS & Notification Automation: Upon identifying the ALARM_TRIGGER string, MacroDroid instantly awakens the phone's location services to pull live GPS coordinates, compiles an emergency message, and transmits an automated SMS containing a Google Maps location link to predetermined emergency contacts. ▼ [ SMS Sent: "ACCIDENT DETECTED + Google Maps Location Link" ]