accelerometer – Tarik Billa

How Nike+ GPS on iPhone receives accelerometer updates in the background?

December 17, 2023 by Tarik

For the sake of providing an answer to this question, even though it is already self answered… “If you use the newer Core Motion API, you can receive updates in the background.” Here is an example: – (void)startAccelerationCollection { [self.motionManager startAccelerometerUpdatesToQueue:[[NSOperationQueue alloc] init] withHandler:^(CMAccelerometerData *data, NSError *error) { dispatch_async(dispatch_get_main_queue(), ^{ [self.accelerometerReadings addObject:data]; }); }]; }

Gyroscope on iPhone

September 24, 2023 by Tarik

[Completely revised] (1) Strange Angles At a first glance I mistook the situation as running into some typical problems related to Euler Angles. Because they are close to this problem area and really important to bear in mind, I leave this part of the original answer. Euler Angle problems are: Ambiguity, as the relationship between … Read more

When to use accelerometer or gyroscope on Android

September 18, 2023 by Tarik

User coverage: Most devices have both gyroscope and accelerometer, but almost every device has an accelerometer. Especially the older devices and the cheaper ones do not have a gyroscope. Don’t forget that since it is a kids app, maybe the parents don’t want the little ones to use their superb 700$ tablet, and will probably … Read more

How to measure the tilt of the phone in XY plane using accelerometer in Android

August 28, 2023 by Tarik

Essentially, there is 2 cases here: the device is laying flat and not flat. Flat here means the angle between the surface of the device screen and the world xy plane (I call it the inclination) is less than 25 degree or larger than 155 degree. Think of the phone lying flat or tilt up … Read more

FFT library in android Sdk [closed]

August 22, 2023 by Tarik

You can use this class, which is fast enough for real time audio analysis public class FFT { int n, m; // Lookup tables. Only need to recompute when size of FFT changes. double[] cos; double[] sin; public FFT(int n) { this.n = n; this.m = (int) (Math.log(n) / Math.log(2)); // Make sure n is … Read more

How do I use the Android Accelerometer?

July 30, 2023 by Tarik

Start with this: public class yourActivity extends Activity implements SensorEventListener{ private SensorManager sensorManager; double ax,ay,az; // these are the acceleration in x,y and z axis @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); sensorManager=(SensorManager) getSystemService(SENSOR_SERVICE); sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER), SensorManager.SENSOR_DELAY_NORMAL); } @Override public void onAccuracyChanged(Sensor arg0, int arg1) { } @Override public void onSensorChanged(SensorEvent event) { if … Read more

Android TYPE_LINEAR_ACCELERATION sensor – what does it show?

July 27, 2023 by Tarik

Very interesting question!!!! I’m developing somethig similar to your application. What i found about TYPE_LINEAR_ACCELERATION isn’t happy for me. 1) TYPE_LINEAR_ACCELERATION, TYPE_GRAVITY, ecc are implemented only for Android 2.3 (and up) So i have Android 2.2 and i can’t test them. 2) TYPE_LINEAR_ACCELERATION isn’t so accurate as it would be, because there are some simple … Read more

Detect change in orientation using javascript

July 16, 2023 by Tarik

NOTE: orientationChange is deprecated Instead use screen.orientation using the screenOrientation interface which is triggered by the screenorientation.onchange event window.addEventListener(“DOMContentLoaded”, () => { const output = document.getElementById(“o9n”); const displayOrientation = () => { const screenOrientation = screen.orientation.type; output.innerHTML = `The orientation of the screen is: ${screenOrientation}`; if (screenOrientation === “landscape-primary”) { console.log(“That looks good.”); } else … Read more

Combine Gyroscope and Accelerometer Data

July 9, 2023 by Tarik

Kalman Filters are great and all, but I find the Complementary Filter much easier to implement with similar results. The best articles that I have found for coding a Complementary Filter are this wiki (along with this article about converting sensors to Engineering units) and a PDF in the zip file on this page (Under … Read more

Understanding FFT output

June 28, 2023 by Tarik

You should neither look for the real or imaginative part of a complex number (that what’s your real and imaginary array is). Instead you want to look for the magnitude of the frequency which is defined as sqrt (real * real + imag * imag). This number will always be positive. Now all you have … Read more