Vibration analysis vs CavernSeer

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.

Designed for cave and shelter surveying, CavernSeer leverages the LiDAR scanner of the 2020 iPad Pro and the iPhone 12 Pro, and RealityKit's scene reconstruction, to generate relatively-accurate 3D meshes of real-world spaces and render them in various convenient ways. ### App Usage ### All iOS/iPadOS 14 devices can run the app and view existing scans shared by others, but devices with a LiDAR scanner (currently iPhone 12 Pros and newer iPad Pros) can capture new scans. ### Viewing ### Scans created by the user or imported from elsewhere will appear in the "Scan List" tab, which lists out the names and the starting photo of the scan. Selecting a scan displays the start and end photos (if available), *export* options for the scan file as well as a plaintext .OBJ render, as well as the following: * Advanced - underlying information about the scan. * 3D Render - a 3D perspective rendering view navigable based on the setting "3D render interaction mode". * Plan Projected Render - a "top-down" orthographic projection complete with scale bar. Defaults to north-up. The height control allows for raising or lowering the camera to show or hide obstructions. * Elevation Projected Render - a "side-view" orthographic projection with scale bar, compass, and various controls. The angle controls change the direction the camera is facing relative to magnetic-north. The depth control is similar to the plan-projected height control, allowing for pushing the camera through obstructions. * Cross Section Render - an elevation projection (see above) with an inset plan-projection indicating the position and size of the camera, and a switch for making the camera "depth-of-field" 1-meter deep to create a cross-section slice. All of the renders support high-resolution screenshots scaled to higher detail than the device itself. ### Scanning ### Devices with a LiDAR scanner can capture new scans in the "Scanner" tab. Pressing the center button starts a scan, after which you can enable Apple's debugging overlays, either showing _Debug_ information or a _Mesh_ preview which displays the currently captured mesh on screen, as well as enabling the device's flashlight. Clicking the center button again will complete and save the scan, which will appear in the scan list. ### Settings ### * Three settings for mesh color change the way that the meshes in the various viewers are displayed. * Switch for changing between meters and decimal-feet in any distance contexts. * Setting for changing the interaction mode in the 3d Render view. The recommended option is "Orbit angle mapping". * Debugging options where appropriate.