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. Vibration 2.00 and later can also sample the built in gyroscope which in some situations is a better indication of vibration or movement than the accelerometer.

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.

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:

• Sample either the built in accelerometer or the gyroscope
• Adjustable sample rate from 10Hz to 100Hz
• Auto repeat and auto save allow data to be taken over extremely long periods of time.
• Selectable data length from 256 to 4096 samples
• Variable start delay from 0 to 20 seconds
• Adjustable vertical scale for time series 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 and peak levels 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 or saving data locally and downloading the data with iTunes
• Turn on and off individual frequency plots
• Calibrate your accelerometers and examine and edit the calibration data
• Optional sounds to mark the start and stop of data acquisition
• Data inspectors and zoom
• Triggering off one or more accelerometer channels or microphone input.

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