Vibra ~ Oscillation Analysis in your Pocket (2015)
Vibra is for use in the structural engineering industry for measuring the oscillation of a structure and reporting if this is within a safe range. This tells you if a structure it sound or not. Specialised companies perform this service charging upwards of 20k. The app performs an FFT analysis on the raw iPhone accelerometer data to filter out the primary and secondary occulting frequencies.
For additional accuracy an external Bluetooth LE sensor could be connected for a higher frequency recordings.
Technical Details
Technology: iOS, FFT, Signal Processing