RMS Displacement Meter

Double integrates the linear acceleration sensor data to get displacement.

This app requires a linear acceleration sensor in your device and Android 7 (Nougat) or above. App Version 1.30. No Ads. Privacy policy.

Link to app on website: https://www.keuwl.com/apps/042rmsdisplacementmeter/

App Summary:

Measures displacement by double integrating the acceleration from your device's linear acceleration sensor.

Note, that this app requires a linear acceleration sensor in your device for it to work. Not all devices with an accelerometer will have the linear acceleration sensor capability.

Any drift or error in the accelerometer and/or other sensor readings is quickly magnified in the double integral, such that even a stationary device will quickly show displacement readings going wild. Therefore this App is for measuring alternating displacements. i.e we apply a drift reduction algorithm to remove any DC component and then measure the AC displacement by means of a Root Mean Square (RMS) value, or perform a Fast Fourier Transform (FFT) to obtain the frequency spectrum.

• Gauge to show the RMS displacement in the X,Y or Z directions, or its magnitude.

• RMS graph to show the gauge readings over time.

• Lower display shows time series data or a FFT from it.

• Peak indicators for the frequency spectrum.

• Save graph data to file.

• Units of cm, mm, m, inches or feet.

An example: Move the device in a circle along two of its axis. You should see two sinusoidal traces 90 degrees out of phase in the time series graph, determine the rotation frequency in the frequency spectrum and obtain an estimate of the diameter of the circle from the gauge or its corresponding graph (when set to peak to peak mode in settings).

Linear acceleration sensors will vary in sampling speed, resolution and accuracy from one device to the next. For indication only.