Insert sensor data from android studio into SQLite database every 1 second? - android-sqlite

Question

I am developing an app using Android Studio which stores the data gathered from the phone's sensors (accelerometer and gyroscope) into SQLite database. The app is working fine and the SQLite database is receiving the inserted values.
The problem now is, it is inserting too many values to the point where it inserts values every microsecond. I have tried every sampling period (SENSOR_DELAY_NORMAL,SENSOR_DELAY_UI) but to no avail. My aim is to only insert values every 1 second to reduce the computing usage. Is it possible to control the rate of data insertion and if so could you guys show me some pointers?
accelerometer & gyroscope listeners:
//Creating the sensor manager; SENSOR_SERVICE is used to access sensors.
sM = (SensorManager) getSystemService(SENSOR_SERVICE);
//Accelerometer Sensor.
accelerometer = sM.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
if(accelerometer != null){
//Register sensor listener;
sM.registerListener(this, accelerometer, 100_000_000);
Log.d("TAG 1 Accelerometer ", "onCreate initializing accelerometer");
} else{
xText.setText("Accelerometer not supported");
yText.setText("Accelerometer not supported");
zText.setText("Accelerometer not supported");
}
//GYRO Sensor.
gyroscope = sM.getDefaultSensor(Sensor.TYPE_GYROSCOPE);
if(gyroscope != null){
//Register sensor listener;
sM.registerListener(this, gyroscope, 100_000_000);
Log.d("TAG 2 Gyroscope", "onCreate initializing gyroscope");
} else{
xTextGyro.setText("GYROSCOPE not supported");
yTextGyro.setText("GYROSCOPE not supported");
zTextGyro.setText("GYROSCOPE not supported");
}
onSensorChanged():
#Override
public void onSensorChanged(SensorEvent event) {
Sensor sensorType = event.sensor;
Location location = null;
if(sensorType.getType()==Sensor.TYPE_ACCELEROMETER) {
accelX = event.values[0];
accelY = event.values[1];
accelZ = event.values[2];
xText.setText("X: " + event.values[0]);
yText.setText("Y: " + event.values[1]);
zText.setText("Z: " + event.values[2]);
xText.setText("X: " + accelX);
yText.setText("Y: " + accelY);
zText.setText("Z: " + accelZ);
} else if (sensorType.getType() == Sensor.TYPE_GYROSCOPE){
xTextGyro.setText("X: " + event.values[0]);
yTextGyro.setText("Y: " + event.values[1]);
zTextGyro.setText("Z: " + event.values[2]);
gyroX = event.values[0];
gyroY = event.values[1];
gyroZ = event.values[2];
}
DatabaseHelper class:
public class DatabaseHelper extends SQLiteOpenHelper {
public static final String SENSOR_TABLE = "SENSOR_TABLE";
public static final String COLUMN_ACCEL_X = "ACCEL_X";
public static final String COLUMN_ACCEL_Y = "ACCEL_Y";
public static final String COLUMN_ACCEL_Z = "ACCEL_Z";
public static final String COLUMN_GYRO_X = "GYRO_X";
public static final String COLUMN_GYRO_Y = "GYRO_Y";
public static final String COLUMN_GYRO_Z = "GYRO_Z";
public static final String COLUMN_CURRENT_SPEED = "CURRENT_SPEED";
private static DatabaseHelper mInstance;
public DatabaseHelper(Context context) {
super(context, String.valueOf(Calendar.getInstance().getTime())+".db", null, 1);
//Date currentTime = Calendar.getInstance().getTime();
// Log.d("TAG DATE", ""+ currentTime);
// super(context, "Live_Test.db", null, 1);
SQLiteDatabase db = this.getWritableDatabase();
}
public static DatabaseHelper getInstance(){
if(mInstance == null){
synchronized (DatabaseHelper.class){
if(mInstance == null){
mInstance = new DatabaseHelper(BaseApp.getApp());
}
}
}
return mInstance;
}
#Override
public void onCreate(SQLiteDatabase db) {
//String createTableStatement= "CREATE TABLE " + SENSOR_TABLE + "( " + COLUMN_ACCEL_X + " REAL, " + COLUMN_ACCEL_Y + " REAL, " + COLUMN_ACCEL_Z + " REAL, time DATETIME DEFAULT CURRENT_TIME)";
String createTableStatement= "CREATE TABLE " + SENSOR_TABLE + "( time DATETIME DEFAULT CURRENT_TIME, " + COLUMN_ACCEL_X + " REAL, " + COLUMN_ACCEL_Y + " REAL, " + COLUMN_ACCEL_Z + " REAL, " + COLUMN_GYRO_X + " REAL, " + COLUMN_GYRO_Y + " REAL, " + COLUMN_GYRO_Z + " REAL, " + COLUMN_CURRENT_SPEED + " REAL)";
db.execSQL(createTableStatement);
Log.d("TAG database :", "DATABASE CREATED");
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS "+SENSOR_TABLE);
onCreate(db);
}
public void insertTable(float x, float y, float z ,float a, float b , float c, double speed){ //put onSensorChanged data to database
ContentValues contentvalues = new ContentValues();
contentvalues.put("ACCEL_X", x);
contentvalues.put("ACCEL_Y", y);
contentvalues.put("ACCEL_Z", z);
contentvalues.put("GYRO_X", a);
contentvalues.put("GYRO_Y", b);
contentvalues.put("GYRO_Z", c);
contentvalues.put("CURRENT_SPEED", speed);
getWritableDatabase().insert(SENSOR_TABLE, null, contentvalues);
}
}

Answer 1

Something like this should help:
#Override
public void onSensorChanged(SensorEvent sensorEvent) {
long now = System.currentTimeMillis();
if(lastSensed + SAMPLING_PERIOD_MS < now) {
// do what you want to do
saveToSQLiteDb();
lastSensed = System.currentTimeMillis();
}
}
When we register the sensor listener, I tried to keep the sampling of that to the default like SensorManager.SENSOR_DELAY_NORMAL, which is like 200,000 microseconds.
That if sentence is satisifed if we keep the SAMPLING_PERIOD_MS to something greater than the default one, so that data is saved to database only after SAMPLING_PERIOD_MS.
Keeping listener's sampling high ensures that fixed interval of delay is achieved