EchoMesh

Mission-critical communication for when every second saves a life

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Inspiration

At IMC, microseconds matter: a split-second delay can mean hundreds of missed trades. In disaster response, delays cost lives. When disasters strike, the internet disappears. Power outages and destroyed infrastructure cut Wi-Fi and cellular networks exactly when coordination matters most - 95% of cellular networks failed during Hurricane Maria (2017). What remains? Walkie-talkies.

Today, volunteers relay messages manually using the phonetic alphabet. This is slow, error-prone, unreliable, and expensive. In noisy, chaotic environments, messages are missed, repeated, or lost entirely. Our system transforms existing walkies-talkies into a fast, automatic, and reliable messaging network — because in disaster relief, every second counts.

What it does

The app acts as an offline, store-and-forward messaging router that transmits text messages over standard walkie-talkies. It enables multi-hop message delivery in environments with no internet or direct radio contact.

How we built it

  • Vite + JavaScript PWA (Progressive Web App) which supports works offline and cross-platform running
  • For audio processing we used the ggwave library for FSK encoding and decoding Web Speech API for Text to Speech and Speech to Text

Challenges we ran into

  • Playback speed of audio was too slow meaning information bandwidth was slow. By adjusting parameters we increased the bit rate to 16 bytes per second (equivalent to 192 wpm) which is comparable to human speech while being significantly more understandable
  • The walkie-talkie could not pick up the frequency range we initially used which we solved by adjusting the protocol to one with a tighter range of frequencies.

Accomplishments that we're proud of

  • The stability of the system: given that signals can be transmitted, they will be transmitted.
  • The app can run cross-platform (phone, laptop etc.)
  • The system is walkie-talkie agnostic; any sort of analogue transmitters (with the appropriate frequencies) works!

What we learned

  • Simple solutions can have profound humanitarian impact.
  • Similar to trading, disaster tech must optimise for speed whilst being 100% reliable and rigorously back tested.
  • Existing daily tools can be transformed through smart software.

What's next for Echo Chain

  • Field testing with Red Cross.
  • Multi-language support for international deployment.
  • Rich training materials for rapid volunteer onboarding.
  • Machine learning on live speech data for immediate emergency response.

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