Hardware guide & bill of materials

Recommended build

Part	Recommended	Notes
Board	Raspberry Pi 5, 8 GB	Pi 4 (4 GB+) also works, a bit slower on the LLM
Storage	32 GB+ microSD, or NVMe via HAT	models are ~1–3 GB total
Microphone	USB mic, or ReSpeaker 2-Mic HAT	far-field arrays improve wake-word later
Speaker	USB speaker, 3.5 mm, or I²S (MAX98357A)	I²S sounds best in a case
Power	Official 27 W USB-C PD (Pi 5)	undervoltage throttles inference
Cooling	Active cooler / fan	the LLM will use all cores
Case	3D-printed (optional)	keep mic ports unobstructed

Choosing models by board

Board	whisper	LLM (Ollama)
Pi 5 (8 GB)	base.en / small.en	llama3.2:3b or qwen2.5:3b
Pi 5 (4 GB)	base.en	llama3.2:1b
Pi 4 (4 GB)	tiny.en / base.en	llama3.2:1b

Smaller models = faster replies. Start small, scale up if latency is acceptable.

Audio setup

1. Plug in the mic and speaker.
2. List devices: arecord -l and aplay -l.
3. Note the card/device (e.g. card 1 → plughw:1,0) and set device in your config.
4. Test capture: arecord -d 3 -f S16_LE -r 16000 -c 1 test.wav && aplay test.wav.

Case & assembly

• Any Pi 5/4 case with an active cooler and openings for the mic/speaker works.
• If you use an I²S DAC/mic HAT, pick a case with GPIO access.
• Keep the microphone away from the speaker to reduce echo (or add a small baffle).

Printable case STLs and a wiring diagram are a great community contribution — PRs welcome to add them under hardware/.