Device Sensor Data Logger (C++)

A C++17 sensor logging application for simulated or serial temperature/light sources. It supports CSV or SQLite persistence, threaded sampling, runtime summaries, threshold alerts, and CSV export.

Features

• Sensor input modes:
  • Simulated sensor mode (Linux/Windows, no hardware needed)
  • Serial sensor mode (Linux UART/USB serial device)
• Logging outputs:
  • CSV file
  • SQLite database (when SQLite3 is available)
• Runtime controls:
  • Start logging
  • Stop logging
  • Show live stats (min/max/avg)
  • Show runtime status (accepted/rejected samples, failures, last reading)
  • Reset session statistics without restarting the app
  • Export logs to CSV
• Safety and observability:
  • Input validation rejects invalid readings such as NaN and negative lux values
  • Configurable alert thresholds for temperature and light
  • Optional --max-samples auto-stop for bounded runs and tests
• Demonstrates:
  • OOP interfaces (ISensor, ILogSink)
  • File I/O and optional SQLite storage
  • Threaded periodic logging loop
  • Basic serial communication parsing

Architecture

• ISensor abstracts data sources. SimulatedSensor generates drifting readings. SerialSensor reads temp,light lines from a serial device on non-Windows platforms.
• ILogSink abstracts persistence. CsvLogSink appends CSV rows. SqliteLogSink stores rows in a sensor_log table and can export them back to CSV.
• DataLogger owns one sensor and one sink, runs the sampling loop on a worker thread, tracks aggregated stats, validates samples, counts failures, and raises threshold alerts.
• StatsAggregator maintains min/max/average for temperature and light.

Build

cmake -S . -B build
cmake --build build

Test

ctest --test-dir build --output-on-failure

The test target covers stats reset logic plus the logger lifecycle, invalid sample rejection, alert tracking, and bounded auto-stop behavior.

Run

Interactive mode (simulated sensor + CSV)

./build/device_sensor_logger --mode sim --output csv --file sensor_log.csv --interval-ms 1000 --temp-alert-max 28 --light-alert-min 100

Then use commands:

• start
• stop
• stats
• status
• reset-stats
• export exported.csv
• quit

Timed run (auto start/stop)

./build/device_sensor_logger --mode sim --output sqlite --file sensor_log.db --duration-sec 20 --max-samples 50 --export out.csv

Serial mode example (Linux)

./build/device_sensor_logger --mode serial --serial-port /dev/ttyUSB0 --baud 115200 --output csv --file serial_log.csv

Expected incoming serial line format:

24.1,315.5

Command Line Options

• --mode sim|serial
• --serial-port <path>
• --baud <rate>
• --interval-ms <milliseconds>
• --output csv|sqlite
• --file <output-path>
• --duration-sec <seconds>
• --max-samples <count>
• --temp-alert-min <value>
• --temp-alert-max <value>
• --light-alert-min <value>
• --light-alert-max <value>
• --export <csv-path>

Example Output

Sensor Data Logger
Commands:
  start              Start logging
  stop               Stop logging
  stats              Show min/max/avg
  status             Show runtime counters and last reading
  reset-stats        Clear collected session statistics
  export <file.csv>  Export log data to CSV
  help               Show commands
  quit               Stop and exit
> start
Logging started.
> status
running=yes accepted=5 rejected=0 read_failures=0 write_failures=0 alerts=1
last=2026-03-12T12:00:05Z temp=28.214C light=92.113 lux

Notes

• If SQLite3 is not found during CMake configure, SQLite output is disabled automatically.
• In serial mode on Linux, ensure your user has permission to access the serial device (for example, group dialout).
• On Windows, serial mode is stubbed out in the current implementation and simulated mode should be used unless Windows serial support is added.