Vibration analysis vs Acc.elerometer

The application analyzes the data from the phone's accelerometer and builds a vibration spectrum. This allows the evaluation of not only the strength and frequency of the vibration, but also the speed of rotation of various mechanisms: fans, motors, various rotating components; since the vibration frequency often (but not always) coincides with the frequency of rotation. The application will be useful in determining the quality of fans and motors, in determining whether their actual parameters coincide with the ones declared by the manufacturer, it will find its uses in monitoring of malfunctions (e.g. in bearings) or while testing the quality of assembly and balancing of the homemade mechanisms with rotating parts. Do not expose your iPhone to an excessive vibration, as it may break. If the analyzed vibration is too strong, use a foam material pad, or put your iPhone at a distance where the force of the vibration is not dangerous to your device. In addition to decreasing vibration for the iPhone, a foam pad improves contact between the iPhone and the vibrating part, which makes the transmission of vibration more accurate and produces better results. BE SURE TO READ THE EXAMPLES OF THE VIBRATION SPECTRUM ANALYSIS AT THE APPLICATION WEB SITE (usefulmobileapps.com). Features of the full version of the application: • The choice of units of measurement. X-axis: Hz or RPM. Y-axis: g, m/s², ft/s², mm/s, in/s (ips), mm, mil, dB(A), dB(V). • FFT size (for built-in accelerometer): 64, 128, 256, 512, 1024, 2048, 4096 (data collection time from 0.64 sec. to 40 sec.). For an accelerometer connected to the headphone jack FFT size from 2048 to 131072. For Bluetooth-accelerometer FFT size from 512 to 32768. • Linear and logarithmic frequency scale. • Linear frequency scale with maximum details (there is a choice for the displayed frequency range). • Peak frequency detection. • Values of any point (for frequency scale and sound wave (at maximum detail)). • Selecting which axis of the accelerometer is to collect data. • Octave bands (1/1,1/3,1/6,1/12). • Window functions (Blackman, Hamming, Hann (Hanning), Blackman–Nuttall, Gaussian, Flat top). • Peak hold. • Exponential spectrum averaging. • Taking a screenshot by lightly touching the screen. • Root mean square (RMS, for vibration) or average value (AVG, for absolute values) for vibration wave. Values are calculated only for data displayed on the screen. • Calibration of the built-in accelerometer. Need EXCLUSIVELY for measuring absolute acceleration values (gravitational acceleration). To activate the settings, turn on the "Vibration wave" mode and turn off the "Only fluctuations" mode. The parameters of the accelerometer depend on the temperature and voltage of the battery, and may change over time. To obtain stable values, the accelerometer should work for several minutes. • Saving the measurement results in the application. Files with saved data (SavedData_[date]_[time].txt) can be copied to a desktop/laptop computer or transferred to another iPhone using iTunes. • Export data to a text ("Y=[y1 y2... yn]", "y1;y2;... yn", "x1;y1\nx2;y2;...") or WAV file. Number of points is adjusted via "FFT size". To export octaves, use "x1;y1\nx2;y2;...". • Accelerometer connects to the headphone jack (measurement range from 5 Hz to 24000 Hz). • A stroboscope for an external accelerometer (the feature was proposed by Todd French from Los Angeles, California). • Bluetooth accelerometer. When converting acceleration into speed or displacement, at 0-5 Hz frequencies noise starts prevailing over vibration peaks, which is why such frequencies are disregarded when doing the conversion. Should vibration frequency exceed 50 Hz, the peak will be recorded at an incorrect frequency, and hence speed or displacement will not be calculated correctly. Unrealistically high speed or large displacement may be a sign of this kind of false frequency.

See how your device moves with Acc.elerometer. View live sensor readings, record an experiment and examine the results on your iPhone or iPad. Capture motion on Apple Watch and send recordings to your paired iPhone for charts and CSV export. EXPLORE SIX MEASUREMENTS - Acceleration, including gravity, in G - User acceleration, with gravity removed, in G - Rotation rate around three axes in rad/s - Magnetic field in microteslas - Device attitude: roll, pitch and yaw in radians - Gravity along each axis in G View individual axes and vector magnitude where supported. Follow changing values and review recorded measurements to explore movement, rotation and orientation. RECORD AND REVIEW Choose the measurements you want to capture, then start and stop a recording. On iPhone and iPad, set the measurement interval from 0.1 to 1 second. Open saved recordings to inspect charts, switch between individual axes and vector magnitude for supported measurements, and identify gaps in the data. EXPORT YOUR DATA Export each measurement from a recording as a CSV file with timestamps and axis values. Choose Unix time, spreadsheet serial dates or formatted date strings for your analysis workflow. CAPTURE MOTION ON APPLE WATCH View sensor readings and record selected measurements on your wrist. Send saved recordings to the paired iPhone and follow transfer progress. Add watch face complications to see saved sensor maxima or recording status, and open the app to start a recording from the recording widget. FOR EXPERIMENTS AND EVERYDAY CURIOSITY Explore device motion for a physics demonstration, a development project or your own experiments. Measurements and recordings are stored on your devices. No account is required. Available readings and actual sampling intervals depend on the device and its sensors. Apple Watch recording duration is subject to watchOS background runtime limits. Watch complications show saved values from the app, rather than a continuous live sensor feed.