accelerometer

I want to find distance traveled and velocity from accelerometer events. Like iphone's gMeter application is doing. Any suggestion, by which value or formula I should use for that? Thanks in advance. You can use the acceleration values from the accelerometer to measure the velocity and distance. There is really good paper ( Implementing Positioning Algorithms Using Accelerometers ) which explains the errors you get from the accelerometer and the techniques to get the velocity and position from the acceleration values. Some pseudo code: velocity[i] = (acceleration[i] + acceleration[i-1])/2 *

Possible Duplicate: Android accelerometer accuracy (Inertial navigation) I am using the following code to calculate the distance. tnew and anew are arraylists containing timestamps and accelerations respectively. double distance=0; double init_vel=0; long time_prev=tnew.next(); while(anew.hasNext()) { float temp_acc=anew.next(); long temp_time=tnew.next(); interval=(temp_time-time_prev)/1000f; //milliseconds to seconds double fin_vel=init_vel+(temp_acc*interval); distance+=(init_vel*interval)+0.5f*temp_acc*interval*interval; init_vel=fin_vel; time_prev=temp_time; } Is there any logical mistake

I have a very basic question. What is Low Pass filter and High Pass filter in case of Android Accelerometer? When I see the output from the Accelerometer Sensor, I see If I don't use any filter, (Case : I kept my cell phone idle on table) I get z Axis +ve value. Now If I think using basic physics, it gives me exact value(9.8approx) for small g i.e Acceleration due to gravity. To get the linear acceleration, If I add any force to phone it will change the Accelerometer value, but it will be g + a that I applied. So to get a why can't I just subtract directly from the value I am getting from

I have raw accelerometer data in form of x,y,z axes which is smoothened and I applied a band pass filter. Now I want to convert it to frequency domain signal and using the scipy.fftpack.fft to apply FFT. sampling_frequency = 32 def fft(acc_data): N = len(acc_data) fft_data = sp.fftpack.fft(acc_data) freqs = sp.fftpack.fftfreq(N) plt.bar(freqs, np.abs(fft_data)) plt.xlabel('Frequency in Hertz [Hz]') plt.ylabel('Magnitude') plt.title('FFT') plt.show() This figure has no points plotted and is empty. The return value of fft is a complex array. I'm using fftfreq to get the frequency of highest

I have to write an application for iphone that tracks the movement of the iphone itself, given its initial position, without ever using GPS. That is, I can only use data provided by the gyroscope and the accelerometer. The distances I need to measure are rather small and the precision I'm looking for is 40-50cm (~2 feet) at the very most. Is this possible? If so, what's the best way to go about it? Also, do you know of any existing (and possibly open source) projects that have implemented this already? Thanks a lot! Ali If you integrate the acceleration twice you get position but the error is

I'm using the following code to get accelerometer data (using CoreMotion framework): CMMotionManager *motionManager = [[CMMotionManager alloc] init]; motionManager.accelerometerUpdateInterval = 1.0 / 60.0; [motionManager startAccelerometerUpdatesToQueue:[NSOperationQueue currentQueue] withHandler:^(CMAccelerometerData *accelerometerData, NSError *error) { NSLog(@"ACCELEROMETER DATA = %@",accelerometerData); }]; When the app is in foreground mode, I'm receiving the log, but when it enters background, I receive the log only when the music in the app is playing. I've added the following to app