Flashlight By Shaking Hand!!

Developer: Engr Saad
Email: saad@triangeltech.com
Website: https://engr-saad.com
LinkedIn: https://www.linkedin.com/in/engr-saad/
Facebook: https://www.facebook.com/Engr.Saad.2/
Company WEB: https://triangletech.com.bd/
WhatsApp: +8801810536303

Summary

The base of this project is LED provided along with the Camera in a typical Android smart phone. After seeing that Play Store has a number of apps that ask for unnecessary permissions, I decided to create an app that toggles the LED without asking for any type of permission. This app also implements a service that detects when the device is shook (used to toggle the flashlight).

As of JAN 3rd of 2020, Flashlight is licensed under Apache License version 2.0.

Downloads

Source Code (zip): Flashlight.zip

Code

The majority of the code is written in Java and is simple. For detecting shake motion: Declare global variables:

    SensorManager sensorManager = null;
    public static final float SHAKE_THRESHOLD = 10.25f; // How hard should user shake to invoke the service
    public static final int MIN_TIME_BETWEEN_SHAKES = 1000;
    private long lastShakeTime = 0;
    private boolean isFlashlightOn = false;

Initialize sensorManager:

    sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
    if (sensorManager != null) {
        Sensor accelerometer = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        sensorManager.registerListener((SensorEventListener) this, accelerometer, SensorManager.SENSOR_DELAY_NORMAL);
    }

Make class implement SensorEventListener interface and override it's onSensorChanged method:

      @Override
    public void onSensorChanged(SensorEvent event) {
        if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
            long curTime = System.currentTimeMillis();
            if ((curTime - lastShakeTime) > MIN_TIME_BETWEEN_SHAKES) {

                float x = event.values[0];
                float y = event.values[1];
                float z = event.values[2];

                double acceleration = Math.sqrt(Math.pow(x, 2) +
                        Math.pow(y, 2) +
                        Math.pow(z, 2)) - SensorManager.GRAVITY_EARTH;

                if (acceleration > SHAKE_THRESHOLD) {
                    lastShakeTime = curTime;
                    if (!isFlashlightOn) {
                        torchToggle("on");
                        isFlashlightOn = true;
                    }
                    else {
                        torchToggle("off");
                        isFlashlightOn = false;
                    }
                }
            }
        }

Create a function torchToggle(String command):

    private void torchToggle(String command) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            CameraManager camManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
            String cameraId = null; // Usually back camera is at 0 position.
            try {
                if (camManager != null) {
                    cameraId = camManager.getCameraIdList()[0];
                }
                if (camManager != null) {
                    if (command.equals("on")) {
                        camManager.setTorchMode(cameraId, true);   // Turn ON
                        isFlashlightOn = true;
                    } else {
                        camManager.setTorchMode(cameraId, false);  // Turn OFF
                        isFlashlightOn = false;
                    }
                }
            } catch (CameraAccessException e) {
                e.getMessage();
            }
        }
    }

Contributing

Any help, including feedback, is highly appriciated. I have just started out with Android and I’m relatively new to app development.

1. Fork it!
2. Create your feature branch: git checkout -b new-branch
3. Commit your changes: git commit -am 'Make a valuable addition'
4. Push to the branch: git push origin new-feature
5. Submit a pull request :D

Don't forget to refer me and give your valuable Star. Happy Coding