Vibration

FEATURES 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 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.

•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 that annoying 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. (Full Version) •Turn on and off individual frequency plots •Level triggering on one or more channels (Full Version) •Calibrate your accelerometers and examine and edit the calibration data (Full Version) •Switchable sounds to mark the start and stop of data acquisition (Full Version) •Double tap to zoom in to examine the data •Switchable 2x and 3x zoom (Full Version) •Touch the screen to bring up a cursor to examine the data. Amplitude and frequency values for the data at the cursor are reported in real time. (Full Version)

USES, BOTH SERIOUS AND FUN 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

•Balance rotating machinery •Measure the vibration spectrum of moving machinery to determine changes in balance due to wear •Use as a prototype platform for testing the functionality of MEMS accelerometers •Easily measure the acceleration of a vehicle during tuning and testing and then send the data to your computer for detailed analysis •Measure the vibration of your kid’s car from that annoying new sub woofer •Quantitatively measure how out of balance your washer is the next time you wash that bedspread •Compare the ride quality of your Volkswagen GTI and your grandfathers Buick •Check the functionality of all three accelerometer axes in your iPhone/iPod •Record accelerometer response to certain inputs during application programming and debugging •Examine the offset and scale factors of the accelerometers in your device

Diffraction Limited Design LLC • Southington, CT USA • 06489 Phone: (860) 276-0450 • Fax: (860) 620-9026 • Contact: Bruce Truax dld-llc.com