Sentinal – Smart Emergency Alert System

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Inspiration

We noticed that in real-life emergencies, people often don’t have the time or ability to unlock their phone, open an app, and call for help. Situations like harassment, accidents, sudden attacks, or panic moments leave users helpless. Existing SOS tools rely on manual activation, which isn’t practical during danger. This motivated us to build a solution that acts automatically — even when the user cannot.

What it does

Sentinal is a smart emergency alert system that automatically detects distress using:

Shake detection Loud scream detection Device drop vibration Side button multi-press

When triggered, it instantly sends an emergency alert with live location, optional camera recording, and an automated message to registered contacts and nearby users. The app can also activate a loud siren, record evidence, and assist with complaint reporting.

How we built it

We developed Sentinal using:

Android Studio + Java Android Sensor APIs for motion, drop, and shake detection MediaRecorder API for auto recording Speech Recognition API for scream detection Location Services API (GPS) for live tracking Firebase Authentication + Firestore for user data Firebase Cloud Messaging (FCM) for push alerts

Multiple triggers were merged with logical safety thresholds to avoid false alarms while maintaining responsiveness.

Challenges we ran into

Fine-tuning sensor responses to avoid false alerts Managing background services without draining battery Handling scream detection accuracy in noisy environments Ensuring emergency alerts work even when the screen is locked Securing user data and alert responses while maintaining speed

Accomplishments that we're proud of

Built a fully functioning real-time alert system Successfully implemented automatic multi-trigger detection Enabled live location sharing and background execution Integrated emergency messaging and recording inside a clean UI Converted a concept into a working Android app in limited time

What we learned

Real-time sensor fusion and calibration Working with background services, permissions, and Android security layers Firebase integration with Java & Android Studio UI/UX design for high-stress emergency situations Optimizing performance for low latency alerts

What's next for Sentinal – Smart Emergency Alert System

Wearable smartwatch integration (SOS + fall detection) Offline Bluetooth mesh networking for no-internet regions AI-based distress classification for smarter decision-making Integration with police, hospitals, and emergency response systems Blockchain-based evidence storage for legal use