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Veetr

Data storage

Documentation for data storage, persistence, and logging in the Veetr system.

Storage Architecture

🌐 Web Dashboard Storage

The web dashboard uses browser-based storage for user preferences and session data:

Local Storage:

  • Connection settings - Previously paired BLE devices
  • User preferences - Dashboard layout, units, themes
  • Calibration data - Wind direction offset, magnetic declination
  • Session state - Last known device connection

Session Storage:

  • Real-time data buffer - Recent sailing data for smooth animations
  • Chart data - Historical data points for graphs and trends
  • Connection status - Current BLE connection state

Implementation:

app/src/utils/storage.ts
// Location: app/src/hooks/useSailingStorage.ts

⚡ ESP32 Firmware Storage

The ESP32 uses EEPROM/NVS (Non-Volatile Storage) for persistent configuration:

EEPROM Storage:

  • Device configuration - Sensor calibration values
  • Network settings - WiFi credentials (if used)
  • BLE settings - Device name, pairing information
  • Sensor offsets - Wind direction calibration, compass deviation

Flash Storage:

  • Firmware updates - OTA update staging area
  • Log buffer - Error logs and debug information
  • Historical data - Trip logs, max values, statistics

Current Partition Layout:

The current flash layout is defined in partitions.csv:

  • nvs: 0x5000 = 20 KB
  • otadata: 0x2000 = 8 KB
  • app0: 0x150000 = 1,376,256 B (~1.31 MiB)
  • app1: 0x150000 = 1,376,256 B (~1.31 MiB)
  • spiffs: 0x150000 = 1,376,256 B (~1.31 MiB)

With OTA enabled, the firmware must fit within one app slot. Unused space inside app0 or app1 is not available for logs unless the partition table is changed.

Implementation:

firmware/src/main.cpp
// Uses: Preferences library for NVS access

Data Flow

Real-time Data:

  1. ESP32 sensors (hardware details) → BLE transmission → Web dashboard
  2. Web storage for immediate display and short-term buffering
  3. No persistent logging of real-time data (by design)

Configuration Data:

  1. Web interface → BLE commands → ESP32 storage
  2. ESP32 EEPROM preserves settings across power cycles
  3. Web localStorage caches settings for faster UI response

Storage Limits

Web Dashboard:

  • LocalStorage: ~5-10MB per domain (browser dependent)
  • SessionStorage: ~5-10MB per tab session
  • IndexedDB: Available for future expansion (large data sets)

ESP32 Firmware:

  • NVS Partition: 20 KB
  • OTA App Slots: 2 x 1,376,256 B (~1.31 MiB each)
  • SPIFFS: 1,376,256 B (~1.31 MiB) available for file storage
  • EEPROM: 512 bytes (compatibility mode)

Current Usage:

  • NVS / Preferences: Used for persistent settings such as calibration, refresh rate, device name, and regatta line coordinates.
  • SPIFFS: Reserved by the partition table, but not currently used by the firmware for real-time sailing logs.
  • Real-time sensor history: Stored in the web app’s IndexedDB, not on the ESP32.

Data Privacy

Local-Only Storage:

  • No cloud storage - all data remains on device
  • No telemetry - no data transmitted to external servers
  • BLE only - direct device-to-device communication

Data Retention:

  • Real-time data: Cleared on page refresh
  • Settings: Persist until manually cleared
  • Logs: Rotate automatically when storage fills

Configuration Management

Calibration Data:

interface CalibrationSettings {
  windDirectionOffset: number;    // Degrees to add to wind direction
  magneticDeclination: number;    // Local magnetic declination
  heelCalibration: number;        // Heel angle zero point
  compassDeviation: number[];     // Compass deviation table
}

Device Settings:

struct DeviceConfig {
  char deviceName[32];           // BLE device name
  uint16_t updateRate;           // Data update rate (ms)
  bool gpsEnabled;               // GPS module enable/disable
  bool imuEnabled;               // IMU module enable/disable
  float sensorOffsets[8];        // Various sensor calibration offsets
};

Backup and Restore

Web Dashboard:

  • Export settings: Download JSON file with all preferences
  • Import settings: Upload JSON file to restore configuration
  • Reset to defaults: Clear all localStorage data

ESP32 Firmware:

  • Factory reset: Clear all NVS storage via BLE command
  • Backup via BLE: Read all settings through web interface
  • Restore via BLE: Write settings from web interface

Future Enhancements

Planned Storage Features:

  • Trip logging: Store sailing sessions with GPS tracks
  • Performance analytics: Historical speed/wind data analysis
  • Cloud sync: Optional backup to user’s cloud storage
  • Export formats: GPX, CSV, JSON data export

Technical Improvements:

  • Data compression: Efficient storage of time-series data
  • Automatic cleanup: Smart storage management and rotation
  • Encryption: Secure storage of sensitive configuration data
  • Versioning: Configuration migration for firmware updates

Implementation Files

Web Dashboard:

  • app/src/utils/storage.ts - Storage utilities and helpers
  • app/src/hooks/useSailingStorage.ts - React hook for sailing data storage
  • app/src/context/BLEContext.tsx - BLE connection and data management

ESP32 Firmware:

  • firmware/src/main.cpp - Main firmware with storage functions
  • Storage libraries: Preferences, SPIFFS, ArduinoJson

This storage architecture ensures reliable data persistence while maintaining user privacy and device performance.

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