+ Post New Thread
Results 1 to 6 of 6
  1. #1
    Member level 2
    Points: 837, Level: 6

    Join Date
    Aug 2012
    Posts
    45
    Helped
    0 / 0
    Points
    837
    Level
    6

    Accelerometer Question

    My accelerometer is showing 1.6v at 0 degree. The voltage goes up turning it one way, and goes downwards the other way. But on 180 degee it shows 1,6v again. Is this correct? How do I know if the accelerometer is 0 degree or 180 degree when they have same output value?

    •   AltAdvertisment

        
       

  2. #2
    Super Moderator
    Points: 251,535, Level: 100
    Awards:
    1st Helpful Member

    Join Date
    Jan 2008
    Location
    Bochum, Germany
    Posts
    43,802
    Helped
    13318 / 13318
    Points
    251,535
    Level
    100

    Re: Accelerometer Question

    How do I know if the accelerometer is 0 degree or 180 degree when they have same output value?
    You'll get more ambiguities by rotating the accelerometer around other axes. For an unequivocal detection of spatial orientation, you need not less than 3 orthogonal accelerometer channels.



    •   AltAdvertisment

        
       

  3. #3
    Member level 2
    Points: 837, Level: 6

    Join Date
    Aug 2012
    Posts
    45
    Helped
    0 / 0
    Points
    837
    Level
    6

    Re: Accelerometer Question

    Thanks, but why do the Accelerometer give the same voltage twice over a 360 degree span?
    Mine give:

    0 - 1.5v
    90 - 2.4
    180-1.5v
    270- 0.8v



    •   AltAdvertisment

        
       

  4. #4
    Super Moderator
    Points: 251,535, Level: 100
    Awards:
    1st Helpful Member

    Join Date
    Jan 2008
    Location
    Bochum, Germany
    Posts
    43,802
    Helped
    13318 / 13318
    Points
    251,535
    Level
    100

    Re: Accelerometer Question

    1.5 V simply means zero g, gravitation force is orthogonal to the direction of sensitivity.

    Think of accelerometer output = a*sin(phi) + b



  5. #5
    Member level 2
    Points: 837, Level: 6

    Join Date
    Aug 2012
    Posts
    45
    Helped
    0 / 0
    Points
    837
    Level
    6

    Re: Accelerometer Question

    OK, I get that. But why is there 0g at 0 and 180 degree?



    •   AltAdvertisment

        
       

  6. #6
    Advanced Member level 5
    Points: 38,220, Level: 47

    Join Date
    Mar 2008
    Location
    USA
    Posts
    6,180
    Helped
    1792 / 1792
    Points
    38,220
    Level
    47

    Re: Accelerometer Question

    Because at zero and 180 to horizontal, your Z acceleration
    is orthogonal to the active axis of measurement and has (by
    design) null output.


    1 members found this post helpful.

--[[ ]]--