FAQ

General

Q: What is FreeBCI DAQ? A: Browser-based EEG acquisition and real-time spectral analysis. All processing is local.

Q: Is it free? A: Yes, AGPL v3 open source.

Q: Does it work offline? A: Core acquisition/analysis yes. AI features need internet (or local Ollama).

Q: What hardware is supported? A: Any EEG device with USB serial (UART) using int24 binary protocol at 921600 baud.

Q: Why only Chrome/Edge? A: Web Serial API is Chromium-only.

Q: Can I use mobile? A: No. Mobile browsers lack Web Serial / USB device access.

Q: Why localhost or HTTPS? A: Web Serial and File System Access API require secure context.

Q: Is data uploaded? A: No. All processing is local. No backend server.

Q: Where is data stored? A: IndexedDB (features), LocalStorage (preferences), memory (raw samples), optional CSV file.

Q: Is my API key safe? A: Stored in IndexedDB, sent only directly to your configured API endpoint.

Q: Why does EI take a few seconds? A: FFT needs a 2-second window of samples.

Q: Why are first 30s excluded? A: Device warmup. Configurable via VITE_INITIAL_UNRELIABLE.

Q: Why is the heatmap incomplete? A: Single effective channel (ch0). Builds from rolling site records.

Q: How accurate is focus classification? A: Binary approximation based on EI median comparison. Not medical grade.

Q: Which models work best? A: GPT-4o, DeepSeek V3, Llama 3 (via Ollama).

Q: Can I use without API key? A: Yes, with local Ollama. No key needed.

Q: Does AI see raw EEG? A: No. Only pre-computed band power values (δ,θ,α,β,γ).

Q: Can I modify the code? A: Yes, AGPL v3. See Developer Guide and Dev Tutorials.

Q: How do I run tests?

npm test
npx vitest run tests/serialEegProtocol.test.ts
npx vitest run -t "test name"

Q: Where are error details? A: Diagnostics drawer (Log button), System page, Browser DevTools (F12).

Q: What does STALLED mean? A: No valid packet for 2s. Auto-recovers when data resumes.

Q: IndexedDB write timeouts? A: Export important conversations, clear old data.