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Tri-axial Accelerometers

  1. Dec 13, 2008 #1
    Hi,

    I am very new to accelerometers and I don't seem to be making any head way with them and I was wondering if someone could tell me what would be my first step in calculating acceleration on the X axis.
     
  2. jcsd
  3. Dec 13, 2008 #2

    brewnog

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    Well the tri-axial bit is irrelevant if you're only considering one axis. What type of accelerometer do you have, and what are you using to measure its output?
     
  4. Dec 14, 2008 #3
    Hi,
    I am concerned with all the axis( X, Y, and Z ) but I figured if I was told how to find one. I would be able to figure out the others. I am using a ±1.5g Three Axis Low-g Micromachined Accelerometer. So far all I am seeing are the accelerometer ADC values

    19.405 2318 2038 2037
    19.605 2320 2044 2036
    19.805 2323 2049 2035

    In the Format: <timeSec> <accX> <accY> <accZ>

    The problem is I don't know what to do with these values to find the acceleration in each of the axis.
     
  5. Dec 14, 2008 #4
    I only worked with an acceleromter briefly 2 years ago as a freshman project, but shouldn't there be some sort of rating for the meter (I think the one I worked with happened to be .01v/g). Knowing the voltage output you can calculate acceleration.

    I did only get a B for the course due to troubles with hooking it up to an 8-digit display, so I probably don't know what I'm talking about. :P
     
  6. Dec 14, 2008 #5
    Hi,

    The voltage output for the
    XOut @ 0g = 1.65V
    YOut @ -1g = 0.85V
    ZOut @ 0g = 1.6V

    I would greatly appreciate it if you could tell me how the voltage output can help you calculate acceleration - Or anyone else that knows and can help me

    Thanks!!
     
  7. Dec 14, 2008 #6
    A spec sheet for your accelerometer may help. Do you have a model number?
     
  8. Dec 14, 2008 #7
  9. Dec 15, 2008 #8
    You have a zero point and a sensitivity for each channel. Basically, using the values given in your data sheet (and comparing to what you've posted):

    Acceleration (g) = (Output in mV - Zero point in mV) / (Sensitivity in mV/g)

    So for example...

    Acceleration (g) = (850 mV - 1650 mV) / 800 mV/g = -1g

    Hope this helps.
     
  10. Dec 15, 2008 #9
    Thanks Man!!

    Much appreciated
     
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