VoiceAlert

Emergency voice alert system for elderly. ESP32-S3 listens for a wake word ("hilfe"/"help"), instantly alerts a remote receiver in another house via MQTT and sends a push notification to your phone via ntfy.sh.

Features

• On-device wake word detection — Picovoice Porcupine, no cloud dependency
• Cross-house alerting — MQTT over internet to a receiver ESP32 that plays a loud siren
• Phone notification — ntfy.sh push with urgent priority (bypasses DND)
• Redundant delivery — MQTT + ntfy in parallel, either channel alone is sufficient
• Multi-room ready — One sender per room, all report to the same receiver
• Zero recurring cost — HiveMQ Cloud free tier + ntfy.sh free

Hardware

Sender (Elder's House)

Part	Model
MCU	ESP32-S3-DevKitC-1-N16R8
Microphone	ICS-43434 I2S (65 dB SNR)
Buzzer	3.3V active buzzer module

Receiver (Your House)

Part	Model
MCU	ESP32-S3-DevKitC-1-N16R8
Amplifier	MAX98357A I2S
Speaker	CQRobot CQR0508 (3W 8Ω)

Setup

See docs/ASSEMBLY_GUIDE.md for full step-by-step instructions.

1. Solder pin headers onto breakout boards (Soldering Guide)
2. Wire components on breadboard (Wiring Reference / Visual Diagram)
3. Create free HiveMQ Cloud account
4. Install ntfy on your phone
5. Fill in config.h with your credentials
6. Flash with PlatformIO

Building

Requires PlatformIO.

# Flash sender
cd sender
pio run --target upload

# Flash receiver
cd receiver
pio run --target upload

Architecture

ELDER'S HOUSE                    YOUR HOUSE
┌──────────┐                     ┌──────────┐
│ ESP32    │──WiFi──▶ MQTT ◀──WiFi──│ ESP32    │──▶ Speaker
│ + Mic    │         broker      │ Receiver │
└──────────┘            │        └──────────┘
                        │
                    ntfy.sh ──▶ Phone push notification

License

MIT