feat: implemented the sound meter (#2739)

Co-authored-by: Anashuman Singh <anash.cheema@gmail.com>

Author: Yugesh-Kumar-S

lib/constants.dart

@@ -166,3 +166,7 @@ String lx = 'Lx';
 String maxScaleError = 'Max Scale';
 String lightSensorError = 'Light sensor error:';
 String lightSensorInitialError = 'Failed to initialize light sensor:';
+String soundMeterError = 'Sound sensor error:';
+String soundMeterInitialError = 'Sound sensor initialization error:';
+String db = 'dB';
+String soundMeterTitle = 'Sound Meter';

lib/main.dart

@@ -13,6 +13,7 @@ import 'package:pslab/view/settings_screen.dart';
 import 'package:pslab/view/about_us_screen.dart';
 import 'package:pslab/view/software_licenses_screen.dart';
 import 'package:pslab/others/theme.dart';
+import 'package:pslab/view/soundmeter_screen.dart';
 import 'constants.dart';
 
 void main() {
@@ -33,6 +34,7 @@ void main() {
 
 class MyApp extends StatelessWidget {
   const MyApp({super.key});
+
   @override
   Widget build(BuildContext context) {
     _preCacheImages(context);
@@ -53,6 +55,7 @@ class MyApp extends StatelessWidget {
         '/accelerometer': (context) => const AccelerometerScreen(),
         '/gyroscope': (context) => const GyroscopeScreen(),
         '/luxmeter': (context) => const LuxMeterScreen(),
+        '/soundmeter': (context) => const SoundMeterScreen(),
       },
     );
   }

lib/providers/soundmeter_state_provider.dart

@@ -0,0 +1,123 @@
+import 'dart:async';
+import 'dart:math';
+import 'package:fl_chart/fl_chart.dart';
+import 'package:pslab/others/logger_service.dart';
+import 'package:flutter_audio_capture/flutter_audio_capture.dart';
+import 'package:flutter/foundation.dart';
+import 'package:pslab/constants.dart';
+
+class SoundMeterStateProvider extends ChangeNotifier {
+  double _currentDb = 0.0;
+  Timer? _timeTimer;
+  final List<double> _dbData = [];
+  final List<double> _timeData = [];
+  final List<FlSpot> dbChartData = [];
+  FlutterAudioCapture? _audioCapture;
+  double _startTime = 0;
+  double _currentTime = 0;
+  final int _maxLength = 50;
+  double _dbMin = 0;
+  double _dbMax = 0;
+  double _dbSum = 0;
+  int _dataCount = 0;
+
+  void initializeSensors() async {
+    try {
+      _audioCapture = FlutterAudioCapture();
+
+      await _audioCapture!.init();
+
+      _startTime = DateTime.now().millisecondsSinceEpoch / 1000.0;
+      _timeTimer = Timer.periodic(const Duration(seconds: 1), (timer) {
+        _currentTime =
+            (DateTime.now().millisecondsSinceEpoch / 1000.0) - _startTime;
+        _updateData();
+        notifyListeners();
+      });
+
+      await _audioCapture!.start(
+        (Float32List audioData) {
+          _currentDb = _calculateDecibels(audioData);
+          notifyListeners();
+        },
+        (error) {
+          logger.e(
+            "$soundMeterError $error",
+          );
+        },
+        sampleRate: 44100,
+        bufferSize: 4096,
+      );
+    } catch (e) {
+      logger.e("$soundMeterInitialError $e");
+    }
+  }
+
+  double _calculateDecibels(Float32List audioData) {
+    if (audioData.isEmpty) return 0.0;
+
+    double sum = 0;
+    for (double sample in audioData) {
+      sum += sample * sample;
+    }
+    double rms = sqrt(sum / audioData.length);
+
+    if (rms <= 0) return 0.0;
+
+    double dbFS = 20 * log(rms) / ln10;
+
+    double dbSPL = dbFS + 94;
+
+    return dbSPL.clamp(20.0, 120.0);
+  }
+
+  void disposeSensors() {
+    _audioCapture?.stop();
+    _timeTimer?.cancel();
+  }
+
+  @override
+  void dispose() {
+    disposeSensors();
+    super.dispose();
+  }
+
+  void _updateData() {
+    final db = _currentDb;
+    final time = _currentTime;
+    _dbData.add(db);
+    _timeData.add(time);
+    _dbSum += db;
+    _dataCount++;
+    if (_dbData.length > _maxLength) {
+      final removedValue = _dbData.removeAt(0);
+      _timeData.removeAt(0);
+      _dbSum -= removedValue;
+      _dataCount--;
+    }
+    if (_dbData.isNotEmpty) {
+      _dbMin = _dbData.reduce(min);
+      _dbMax = _dbData.reduce(max);
+    }
+    dbChartData.clear();
+    for (int i = 0; i < _dbData.length; i++) {
+      dbChartData.add(FlSpot(_timeData[i], _dbData[i]));
+    }
+    notifyListeners();
+  }
+
+  double getCurrentDb() => _currentDb;
+  double getMinDb() => _dbMin;
+  double getMaxDb() => _dbMax;
+  double getAverageDb() => _dataCount > 0 ? _dbSum / _dataCount : 0.0;
+  List<FlSpot> getDbChartData() => dbChartData;
+  int getDataLength() => dbChartData.length;
+  double getCurrentTime() => _currentTime;
+  double getMaxTime() => _timeData.isNotEmpty ? _timeData.last : 0;
+  double getMinTime() => _timeData.isNotEmpty ? _timeData.first : 0;
+  double getTimeInterval() {
+    if (_currentTime <= 10) return 2;
+    if (_currentTime <= 30) return 5;
+    return 10;
+  }
+}

lib/view/instruments_screen.dart

@@ -61,6 +61,18 @@ class _InstrumentsScreenState extends State<InstrumentsScreen> {
           );
         }
         break;
+      case 15:
+        if (Navigator.canPop(context) &&
+            ModalRoute.of(context)?.settings.name == '/soundmeter') {
+          Navigator.popUntil(context, ModalRoute.withName('/soundmeter'));
+        } else {
+          Navigator.pushNamedAndRemoveUntil(
+            context,
+            '/soundmeter',
+            (route) => route.isFirst,
+          );
+        }
+        break;
       default:
         break;
     }