The idea for Silent Signal came from frustrating experiences in remote meetings where participants unknowingly transmitted distracting background noise. While tools like Zoom offer basic noise suppression, they don’t proactively alert the speaker unless someone speaks up. We wanted to create a real-time, privacy-first solution that subtly detects and notifies users when their environment becomes disruptive, without requiring others to intervene.
What it does
Silent Signal monitors ambient noise through the user's microphone, calculates decibel levels in real-time using the Web Audio API, and alerts users when noise exceeds a customizable threshold. The app logs violations to a backend via API Gateway and AWS Lambda, stores history in DynamoDB, and can optionally send email notifications using Amazon SES. It visualizes noise trends in the frontend UI, giving users insight into their environment and helping reduce meeting interruptions.
How we built it
Frontend: Built with React.js and styled using Tailwind CSS. It uses the Web Audio API to capture microphone input, compute real-time dB levels, and render visual feedback.
Backend: Powered by AWS Lambda (Python), with endpoints exposed via Amazon API Gateway. Noise data is parsed, analyzed, and logged into DynamoDB. Alerts are sent via Amazon SES.
Infra & Tools: Deployed and tested using AWS SAM and the AWS CLI. Postman was used for API testing, and the frontend was hosted on Vercel.
- Additional Features: Includes browser-native push notifications and optional sound classification logic (ML model or Bedrock).
Challenges we ran into
Cross-browser mic access: Different browsers handle permissions and audio processing inconsistently.
Accurate decibel readings: Balancing reliability without needing physical calibration.
Real-time performance: Processing mic input efficiently without slowing down the browser.
Deployment: CORS issues, API Gateway misconfigurations, and Lambda timeouts required debugging.
- Privacy: Designing a system that keeps sensitive mic data local while still enabling useful backend logging and alerts.
Accomplishments that we're proud of
Built a full-stack, serverless system in just 14 days with reliable end-to-end functionality.
Successfully integrated SES for automated email alerts and overcame CORS issues in production.
Created a clean, responsive UI that works in real-time across devices and browsers.
- Implemented a local-only audio processing pipeline to respect user privacy while maintaining functionality.
What we learned
Using AWS SAM to manage and deploy serverless functions efficiently.
Configuring IAM roles and understanding AWS permissions for Lambda, SES, and DynamoDB.
Implementing real-time mic analysis with the Web Audio API and tuning it for responsiveness.
Managing API Gateway settings to support CORS and safe public access.
- Building user-centric features that maintain privacy while still offering practical noise insights.
What's next for Silent Signal
Slack/Discord integration for real-time team alerts.
Auth & multi-user support with AWS Cognito for secure team-based usage.
Log exports (CSV/Excel) and advanced analytics dashboards.
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