accelerometer

I have read various posts here at StackOverflow regarding the execution of FFT on accelerometer data, but none of them helped me understand my problem. I am executing this FFT implementation on my accelerometer data array in the following way: int length = data.size(); double[] re = new double[256]; double[] im = new double[256]; for (int i = 0; i < length; i++) { input[i] = data[i]; } FFT fft = new FFT(256); fft.fft(re, im); float outputData[] = new float[256]; for (int i = 0; i < 128; i++) { outputData[i] = (float) Math.sqrt(re[i] * re[i] + im[i] * im[i]); } I plotted the contents of

It seems that we can not get sensor data in the web workers. I wonder the reason behind it. The use case is that I am thinking about getting geolocation data in the worker thread and only send the processed version to the main thread. For GPS, this post says it is not supported in the worker thread (no reason is given). And I double checked it, navigator.geolocation is not supported in web workers. For accelerator and gyroscope, we have DeviceOrientationEvent and DeviceMotionEvent. But we need to use them through the window object, which is not available to the worker thread. The same

I would like to know if there are some libraries/algorithms/techniques that help to extract the user context (walking/standing) from accelerometer data (extracted from any smartphone)? For example, I would collect accelerometer data every 5 seconds for a definite period of time and then identify the user context (ex. for the first 5 minutes, the user was walking, then the user was standing for a minute, and then he continued walking for another 3 minutes). Thank you very much in advance :) Ali I don't know of any such library. It is a very time consuming task to write such a library. Basically

I'm trying to implement Madgwick sensor fusion algorithm from here on LSM9DS0 sensor (accelerometer, gyroscope and magnetometer) on STM Cortex M3 microcontroller. Raw data from all sensors seems to be fine. My problem is: when I hold sensor with it's z-axis horizontal or downwards (i.e. roll or pitch angle is more than 90 degrees) - quaternion from filter becomes really unstable and randomly flips 180 degrees. More correctly, q0 and q3 are constantly changing signs, resulting in 180 degree flip of rotation. I tried using constant values instead of real sensor output and still got this behavior

I'm writing a small sample application for the Windows Phone 7.1 (Mango) and want to use the Combined Motion API to display the motion of the device. I need to write mock classes to be able to test my application when using the emulator which does not support all sensors of the device. I already wrote a simple mock class to simulate a compass (it just simulates a rotating device) and for the accelerometer which is actually available in the emulator. Now I would have to write a new mock object for the Motion API but I hope that I could calculate the values that are used for the Motion object

My app simply need to detect any motion of the device while screen is off. I know that accelerometer is used for this task but it don't work while screen is off in all devices. this is a list of devices http://www.saltwebsites.com/2012/android-accelerometers-screen-off so is there a way of taking accelerometer sensor data while screen is off that works on all devices? or is there a way to detect motion using another sensors? Partial Wake Lock is all you need to access accelerometer readings while the screen is off. You can use it like this: private PowerManager.WakeLock mWakeLock; PowerManager