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Problems reading from accelerometer — Parallax Forums

Problems reading from accelerometer

trannhtrannh Posts: 24
edited 2012-06-01 14:27 in BASIC Stamp
Here is the program I am trying to run. Everything runs perfect except for the acceleration values. They are not outputting the correct values I think. I am using the MMA7455L 3-axis accelerometer from Parallax. Can someone please help me figure out the problem as soon as possible? I would greatly appreciate the help.
bpx
bpx
FinalProgram2.bpx
8K

Comments

  • FranciscoTavaresFranciscoTavares Posts: 27
    edited 2012-06-01 12:37
    I´m having a problem with acceleration values as well. The values changes too much even when the device is not moving.
    I tried to adjust ofsets


    Offset values FOR each axis:
    'Offset values FOR each axis:
    XCal CON 25 'VAR Word
    YCal CON 80 'VAR word
    ZCal CON 0 'VAR Word


    but even so the values for XAccel changes like these ones captured from my accelerometer (see atached figure):
    Accelerometer.jpg
    943 x 563 - 295K
  • ercoerco Posts: 20,257
    edited 2012-06-01 14:27
    AFAIK, a narrow range of numbers (as your screenshot shows) is normal. You have to sample rapidly, take lots of moving averages, and use filters to get fairly accurate trends.
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