VibrationVersion: 1.40 (iPhone OS 3.0 Tested)

Vibration is a true vibration spectrum analyzer using the built in accelerometers inside the iPod Touch and the iPhone. It acquires and displays time series data, optionally removes DC bias, applies a Hamming window and performs an FFT on each channel to produce frequency spectra. The 3-channel accelerometer has a sensitivity of approximately 0.02g and a range of ±2g making the iPhone and iPod Touch sensitive enough to analyze the vibration of most moving machinery.

In many applications Vibration can be an excellent portable alternative to a commercial spectrum analyzer. In predictive maintenance applications Vibration can help identify bearing defects, shaft misalignment, imbalance, and structural resonant frequencies. Vibration is also useful for monitoring the acceleration of part and material handling equipment.

Vibration is also an excellent tool for iPod and iPhone game programmers. The application provides an ideal way to record the output of the accelerometers for particular user actions. This data can then be plotted offline allowing the programmer to best determine how to process the data.

The software is flexible and easy to use. It was written to emulate the familiar oscilloscope based spectrum analyzer. Sample rate and sample delay are easily adjustable using sliders and the user can select the length of the data acquisition and the vertical scale used for the display. Once the settings are configured simply press the sample button. When a test is complete the resulting data can be emailed to your desktop computer for documentation purposes.

Features:

• Adjustable sample rate from 10Hz to 100Hz
• Selectable data length from 128 to 1024 samples
• Variable start delay from 0 to 20 seconds
• Adjustable vertical scale for both time series and frequency data
• DC Remove option to get rid of the gravity vector
• Switchable Hamming window for frequency analysis
• Frequency data plotted as Linear-Linear, Log-Log, Log-Linear and Linear-Log
• Computes rms vibration for each channel and for all three channels combined
• Document your results by taking screen snapshots and syncing them to your computer or sending a CSV formatted email with the time and frequency data to your computer
• Turn on and off individual frequency plots
• Calibrate your accelerometers and examine and edit the calibration data
• Switchable sounds to mark the start and stop of data acquisition
• Data inspectors and zoom
• Triggering off one or more channels

Further development and additional features are planned. Please use the email links in the program to request new features and report any problems.