Making High Resolution Vibration Measurements with a Low Cost Audio Recorder

Session details:

Handheld digital data collectors have been used by vibration analysts since the 1980s. Over the decades, several models have been introduced by various companies, with most contributing to a rise in the average cost to the user. Much of the increased cost is due to increased performance but also the expansion of features, such as the color display and the embedded signal processing. Higher performance requires more processor power, memory, and battery capacity – all adding to the costs.

Lower cost means of capturing vibration data have come on the market over the years in the form of accelerometers with embedded data acquisition (A/D converter), but also requiring the device to be tethered to a laptop, limiting their utility in the field.

But it turns out that there are devices readily available on the market today that are not only very low cost and highly portable but have more than enough data acquisition fidelity to satisfy most vibration analysts.

In this paper we describe how several audio recorders on the market today might serve as vibration data collection devices in some applications. Designed to capture high fidelity audio signals from an attached microphone, these devices can be repurposed to capture vibration signals with both high resolution (32-bit floating point provided by two 24-bit A/D converters) and high sample rates (48ksps) from an accelerometer with modified output circuitry. With both embedded memory and use of external MicroSD cards (512GB to 1TB) these devices can collect hours of vibration data.