We manufacture accelerometers here at Freescale. The ones I am familiar with work like this: When the part is moved, the movement amount is measured and stored internally as XYZ coordinates. The application has to use I2C or SPI to communicate with the accelerometer to get the XYZ coordinates. To sense vibrations, you would have to constantly query the device to get the XYZ coordinates, and subtract the (N)th coordinates from the (N-1)th coordinates. This gives the amount of movement in each direction. Accelerometers are commonly used in applications that need to sense a sudden movement, such as a car crash to deploy air bags, or sensing when your iPhone is turned sideways to put the picture in landscape mode, etc. It can detect vibrations because there would be small movements in several directions. This would require fast polling of the device.
To poll the device continuously would require separate hardware and a program. NI makes a NI-USB-8451 I2C/SPI device that costs a few hundred dollars. Labview drivers come with this device. A simple Labview program could be written to detect movement. But I would think there might be an easier and cheaper way to detect vibration. Perhaps a search for vibration detection on Google. If you want an accelerometer to play with, I think you can get a Freescale device from parts houses such as Newark or Digi-Key. We make a wide variety of acceleromters. Some detect on only one axis, some on two, and some on all three axes.
tbob
