Alpine Meadow / Interstate 75 Noise Levels

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.