🚨 ClearAlert

Offline-First Emergency Alerts for Vulnerable Communities

ClearAlert is an offline-resilient emergency alert system designed to ensure people receive clear, accessible, and personalized alerts during extreme weather — even when internet connectivity fails.

Built for ElleHacks 2026 under the theme Tech for Equity & Social Good. ClearAlert is driven to solve Challenge 2: Sustainability🌱💭 @ ElleHacks'26

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🌍 Why ClearAlert

During emergencies, alerts often fail when they’re needed most:

• Internet and power outages disrupt notifications
• Alerts are unclear, text-heavy, or not in the user’s language
• Vulnerable communities (seniors, newcomers, students living alone, rural areas) are disproportionately affected

ClearAlert addresses this gap by delivering multilingual audio alerts locally, without relying on constant connectivity.

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✨ What It Does

🌐 Web App (Online Mode)

• Users enter their location
• Select preferred language
• Add personal context (pets, vision impairment, medical needs, etc.)
• View clear explanations + recommended actions

🔊 Offline Alerts (Emergency Mode)

• A Raspberry Pi 4 polls the system every 5 seconds
• When an alert escalates (SAFE → WARNING → EMERGENCY), it plays a multilingual audio alert locally
• Cached alerts ensure instructions are still delivered if the internet goes down

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🧠 Key Features

• Offline-first architecture
• Multilingual, accessible audio alerts
• Personalized emergency guidance
• Low-cost hardware deployment
• Designed for real-world failure conditions

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🛠️ Tech Stack

Frontend

• TypeScript + React + Next.js
• Location-based input & personalization UI

Backend

• Python + Flask API
• Alert logic & risk classification (SAFE / WARNING / EMERGENCY)

Hardware

• Raspberry Pi 4
• Bluetooth speaker for local audio playback
• Local caching for offline resilience

Generative AI

• ElevenLabs – multilingual, natural-sounding voice alerts (pre-generated & cached)
• Google Gemini API – personalized emergency recommendations based on user context (medical needs, disabilities, household type)

Other APIs used to fetch realtime alert data

• OpenStreetMap Nominatim API : Free geocoding service, converts location text (city, postal code) to coordinates Returns country codes, state/province info
• Environment Canada GeoMet OGC API (Canada) : Canadian government weather alerts
• GDACS (Global Disaster Alert and Coordination System) : UN-backed global disaster monitoring, covers earthquakes, floods, cyclones worldwide

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Algorithms & Logic

Haversine Formula

• Calculates distance between two geographic coordinates (lat/lon)
• Used to filter GDACS alerts by proximity (within 300km)

Alert Severity Mapping

• Normalizes severity levels from different sources to unified scale: low, moderate, severe, extreme on the website
• Maps NWS severity, GDACS alert levels, and Environment Canada urgency

24-Hour Date Filtering

• Validates alert timestamps to only show recent alerts
• Filters out stale/expired alerts

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🧩 System Architecture (High-Level)

Web App (React)
↓
Backend (Flask)
↓
Raspberry Pi (polls every 5s)
↓
Local Audio Playback (cached MP3s)

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Data Flow Diagram

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🏆 Accomplishments

• Built a fully functional end-to-end prototype
• Implemented offline caching for emergency reliability
• Delivered personalized, multilingual audio alerts
• Designed explicitly for vulnerable communities

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🔮 What’s Next

• Integrate live weather APIs for real deployments
• Expand accessibility options (slower speech, visual indicators)
• Add SMS / mesh fallback communication
• Pilot with community organizations and real users