03-private-speaker: Reading

Class 13: Private smart speaker — Class 13 visual reference. Use it as the map, then prove it in the reading, lesson, and lab.

Overview

Module: Module 4: Local Voice Assistant
Topic: 03: Private smart speaker
Activity type: Reading / reference (Learn)
Bloom focus: Create / Evaluate
Links to outcome: Given working STT/TTS providers, the learner can integrate wake → action → spoken response and prove an internet-disconnected end-to-end pass with staged gates.

Why it matters

Why this matters

Integrate a voice satellite, wake-word engine, VAD/audio transport, Whisper, Home Assistant Assist, local intent or conversation processing, Piper, and speaker playback. The final privacy requirement is demonstrated behavior under WAN disconnection, not a marketing label.

Words

Vocabulary

Add terms as you encounter them in Instruction.

Learn

Core reading

System boundary

flowchart TD
    S["Satellite mic + speaker"] --> W["Wake word + capture"]
    W --> STT["Local Whisper"]
    STT --> HA["Home Assistant Assist"]
    HA --> E["Local entity/action"]
    HA --> TTS["Local Piper"]
    TTS --> S

Optional local LLM conversation belongs behind a routing decision. Deterministic home-control commands should not require an open-ended model unless the design explicitly accepts the latency and failure modes.

Satellite responsibilities

Depending on hardware/software, the satellite may handle microphone capture, wake word, VAD, audio streaming, playback, LED state, and local buttons. Record where each responsibility executes; otherwise failures are impossible to localize.

Example responsibility map:

Function	Location
Microphone capture	Satellite
Wake word	Satellite or central service, choose and record
STT	Local server
Intent/action	Home Assistant
LLM, if used	Local compute node
TTS	Local server
Playback	Satellite

Progressive integration gates

Do not skip gates:

Gate A: audio hardware

Record and play a known sample locally. Validate device selection, gain, clipping, channels, sample rate, echo, and speaker route.

Gate B: wake word

Run repeated positive and negative trials. Record threshold/model and test distance.

Gate C: STT

Prove the known sentence transcript. Preserve captured audio for comparison.

Gate D: HA understanding

Enter transcript as text. Confirm correct intent, area, entity, and action.

Gate E: action

Confirm entity reaches the requested state and record HA trace/log.

Gate F: TTS and playback

Synthesize a fixed response and play it through the satellite.

Gate G: end to end

Speak wake word and command. Capture timestamps at wake, end-of-speech, transcript, intent, state change, synthesis, and playback.

Gate H: offline privacy

Disconnect WAN access while preserving the LAN. Repeat the full command and a second informational command that is defined as local. Verify DNS or cloud dependencies do not silently block the pipeline.

Local LLM routing

If you add an LLM, whitelist only low-risk intents. Lights/locks/garage need deterministic intents, not open-ended chat.

Reliability and recovery

Document restart order: network → HA → Wyoming STT/TTS → satellite. Keep a known-good backup of HA and satellite config.

I do

Worked example (study this)

I do: study the reasoning, not just the final answer.

Bad acceptance: “It worked once while Wi-Fi was up.”

Better: Progressive gates: wake only → STT → intent/action → TTS → full path: then repeat with internet disconnected and record the pass.

TipCurrent correction

Use the lecture as a system-integration example. Hardware support, satellites, add-ons, repositories, and Home Assistant pipeline screens change. Current official documentation and the staged acceptance tests in this class govern the build.