CrisisNet

CrisisNet is an offline emergency app using Wi-Fi Direct and Bluetooth mesh to send text, image, and voice SOS alerts to nearby devices when networks fail — no SIM, no internet needed.

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🚨 CrisisNet: The Offline Emergency Network

📌 What Inspired Us

During heavy floods in my hometown last year, mobile networks went down for hours. People couldn’t contact emergency services or even reach their families. It made me realize how dependent we are on the internet during disasters, and how helpless we become without it. That experience inspired me to create CrisisNet — a solution that lets people communicate during network failures using the devices they already have.

📚 What We Learned

Building CrisisNet taught us a lot about mesh networking protocols, peer-to-peer device communication, and offline-first mobile design. We explored how Wi-Fi Direct and Bluetooth can be leveraged to build a self-sustaining communication grid without relying on traditional infrastructure. We also learned about optimizing battery consumption and managing device discovery cycles for power efficiency in emergencies.

🛠️ How We Built It

We used Bolt.io to prototype the app, integrating Wi-Fi Direct and Bluetooth APIs for device discovery and message relaying. The UI was designed to be clean and minimal with a dark, emergency-themed interface. We created features for sending text messages, voice notes, and images, which hop between nearby devices until reaching someone who can assist.

⚙️ Challenges We Faced

One major challenge was ensuring consistent device discovery in unstable conditions, and managing message propagation without duplication. Handling simultaneous Wi-Fi Direct and Bluetooth connections smoothly while keeping battery usage low was also tricky. We had to carefully balance offline reliability, speed, and power efficiency in an unpredictable network environment.

What's next for CrisisNet

Our next goal is to make CrisisNet even smarter and more versatile. We plan to implement automatic distress detection through voice and motion triggers, where the app can detect abnormal sounds like calls for help or sudden device shakes and automatically send out an SOS message.

We also aim to integrate a real-time location heatmap showing areas with active SOS messages to help responders identify critical zones faster. In future iterations, we hope to enable multi-device message relaying over larger distances, optimizing message routing based on signal strength and available devices in range.

Additionally, we’re exploring ways to connect CrisisNet to existing disaster management systems and local authorities, ensuring that offline distress signals can be delivered to official emergency teams when at least one device in the mesh network regains internet access.

Our long-term vision is to turn CrisisNet into a go-to safety tool not just for disaster scenarios, but for everyday student safety on campuses, remote travel, and offline adventure trips where network availability is uncertain.

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