Grove PM2.5 Monitor BLE Project

A PlatformIO project for the Seeed Wio Terminal that reads data from a Grove HM3301 PM2.5 laser dust sensor and broadcasts the readings over Bluetooth Low Energy (BLE).

Hardware Requirements

• Seeed Wio Terminal
• Grove HM3301 Laser PM2.5 Sensor
• microSD card (FAT32 formatted)
• I2C grove connection

Features

• Real-time particulate matter measurements:
  • PM1.0 (atmospheric)
  • PM2.5 (atmospheric)
  • PM10.0 (atmospheric)
• BLE connectivity:
  • Device name: "PM2.5 Sensor"
  • Real-time data notifications
  • Historical data access
• TFT display showing:
  • Current PM readings
  • BLE connection status
  • Debug information
• Data logging:
  • Readings logged every 5 minutes to SD card
  • CSV format with timestamps
  • Automatic file management
• Historical data:
  • Hourly averages calculation
  • 24-hour history retention
  • Accessible via BLE
• Time synchronization:
  • Set the device time via BLE
• Alerting:
  • BLE alerts for high PM2.5 levels

BLE Service Specifications

• Service UUID: 91bad492-b950-4226-aa2b-4ede9fa42f59
• Characteristics:
  • PM1.0: 91bad493-b950-4226-aa2b-4ede9fa42f59 (Read, Notify)
  • PM2.5: 91bad494-b950-4226-aa2b-4ede9fa42f59 (Read, Notify)
  • PM10: 91bad495-b950-4226-aa2b-4ede9fa42f59 (Read, Notify)
  • History: 91bad496-b950-4226-aa2b-4ede9fa42f59 (Read)
  • Time Sync: 91bad497-b950-4226-aa2b-4ede9fa42f59 (Write)
  • Alert: 91bad498-b950-4226-aa2b-4ede9fa42f59 (Read, Notify)

BLE Client/Central Example App

• Flutter PM2.5 Monitor App

Dependencies

• Seeed_HM330X (Grove PM2.5 Sensor Library)
• Seeed_Arduino_rpcBLE
• Seeed_Arduino_rpcUnified
• TFT_eSPI
• Seeed_Arduino_FS
• Seeed_Arduino_RTC

Data Storage

• Data is stored in /data/PM_xxxx.csv files on the SD card
• CSV format: Power_Cycle,Timestamp,PM1.0,PM2.5,PM10,Uptime_Sec
• Power cycles are tracked in /data/power_cycle.txt

Update Intervals

• Sensor readings: Every 5 seconds
• Data logging: Every 5 minutes
• Hourly averages calculation: Every hour