hi....

i want measure tilt angle with 0.2degree resolution .so any one can tell me i cant achive it with adxl345 or not if yes then tell me what is min resolution in angle ..

hi....

i want measure tilt angle with 0.2degree resolution .so any one can tell me i cant achive it with adxl345 or not if yes then tell me what is min resolution in angle ..

Hi Sandip,

As you know, there are plenty of error source that can influence the accuracy of the inclinometer, such as noise, offset, tempco...

Refer to the resolution, it is decided by the noise of the part. The X, Y axes RMS noise of ADXL345 is 0.75 LSB (0.75lsb * 3.9mg/lsb = 2.93mg), this means 0.17 deg resolution. So, 0.2 degree resolution can be met.

Refer to other error source, hope the attached slide can help you.

BR

Neil

hi Neil, thank you for your reply it clear my dought, attched pdf is heplfull for me,i want to ask you ,i use ADXL345,for finding angle is ther need all x,y,z reading,there are two formule

Angle = ARCTAN (XOUT / YOUT)

xAngle = atan(ax/(sqrt((ay*ay)+(az*az))));

what is difference in these two formule

Hi Sandip,

Please see the AN from the link http://www.analog.com/media/en/technical-documentation/application-notes/AN-1057.pdf. I did not know why I cannot upload the document today, I had tried two times.

BR

Neil

Hi Sandip,

When the board is vertical to the ground, the Z axis = 0g. You can use:

Angle = ARCTAN (XOUT / YOUT)

When there is component of gravity on Z axis, you can use:

xAngle = atan(ax/(sqrt((ay*ay)+(az*az))));

You can always use xAngle = atan(ax/(sqrt((ay*ay)+(az*az))));

When Z axis = 0g, it will change to:

Angle = ARCTAN (XOUT / YOUT).

BR

Neil

Hi Sandip,

When the board is vertical to the ground, the Z axis = 0g. You can use:

Angle = ARCTAN (XOUT / YOUT)

When there is component of gravity on Z axis, you can use:

xAngle = atan(ax/(sqrt((ay*ay)+(az*az))));

You can always use xAngle = atan(ax/(sqrt((ay*ay)+(az*az))));

When Z axis = 0g, it will change to:

Angle = ARCTAN (XOUT / YOUT).

BR

Neil