This noise monitoring system tracks sound levels from Interstate 75 near Alpine Meadow using:
- Raspberry Pi Zero 2 W (512MB RAM)
- PCB Artists I2C Decibel Sound Level Meter
ARM Cortex M4 processor with pre-calibrated dB SPL output
Designed according to IEC 61672 Class 2 guidelines, but it is not formally certified
- PiSugar 3 UPS Battery Module
1200mAh battery with built-in RTC (Real-Time Clock)
Provides uninterruptible power during outages and maintains accurate time
- MQTT over WebSocket
For real-time data streaming with local database persistence
Data is measured continuously and stored locally in a SQLite database, then published to a cloud MQTT broker for real-time display. The system operates 24/7 with full offline capability - during internet or power outages, all data is preserved locally and automatically syncs when connectivity returns.
All measurements are in A-weighted decibels (dBA), the standard for environmental noise monitoring.
Weather Flagging: Readings taken during precipitation or high wind (≥15 mph) are automatically flagged. These conditions can affect microphone accuracy, so flagged readings are recorded but may be excluded from statistical calculations.