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How to find 'g' from a MEM's Device (Shimmer IMU)?

  1. Aug 22, 2012 #1
    Hello all,
    I'm working with an accelerometer to detect movement and i'm using Shimmer IMU. I got values ranging somewhere between 1000 and 2000. My question is, are these values the output of the ADC? And how do i calculate 'g' from the values?
    I have attached an xls file with the experiment readings.
    Thank you

    Attached Files:

  2. jcsd
  3. Aug 22, 2012 #2
    The device must have some documentation with it. Which should explain what those values are.
  4. Aug 22, 2012 #3


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    Probably the easiest way would be to just calibrate it using earth's gravity - most accelerometers output voltage is linearly proportional to the acceleration, so all you need is two points to calibrate it. If you hold it vertically, such that the measurement axis is aligned with the gravitational force, you can get one such calibration point (9.8 m/s^2), and then you can get the second calibration point by holding it horizontally (0 m/s^2) or upside down (-9.8 m/s^2). You could even do all three, and then do a best fit line to determine a slightly more accurate reading.

    Alternatively, there's probably a spec sheet somewhere, but how useful it is will depend on your setup.
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