What is the scale factor for Accelerometer?
I received raw accelerometer data but how can convert to g?
I received mostly -160,80,4032 accelerometer data as x,y,z when staying stable position; but how can convert it to calculated accelerometer data?
BNO085 Accelerometer Scale Factor
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- millercommamatt
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Re: BNO085 Accelerometer Scale Factor
Which library are you using and it there a reason you are raw ADC values and not the translated values the Adafruit libraries provide?
An you using specific example code? If so, what?
An you using specific example code? If so, what?
- gammaburst
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Re: BNO085 Accelerometer Scale Factor
demir's question was cross-posted in this discussion:
viewtopic.php?f=19&t=179820&p=875668#p875668
viewtopic.php?f=19&t=179820&p=875668#p875668
- sj_remington
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Re: BNO085 Accelerometer Scale Factor
If the accelerometer is held still, with any axis perfectly vertical, the acceleration is exactly +/- 1 g along that axis.
Use that fact and the raw data to figure out the scale factor and offset for each axis.
Use that fact and the raw data to figure out the scale factor and offset for each axis.
- gammaburst
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Re: BNO085 Accelerometer Scale Factor
No, gravity varies by about 0.7% due to Earth's irregular shape and composition.
Also, Earth's rotation reduces your apparent gravity as you approach the equator.
The Sun's and Moon's positions also have a slight effect (think tides).
Also, Earth's rotation reduces your apparent gravity as you approach the equator.
The Sun's and Moon's positions also have a slight effect (think tides).
- sj_remington
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Re: BNO085 Accelerometer Scale Factor
Correct, but unfortunately, the BNO085 cannot detect those slight variations.
Which is why most people assume exactly 1 g for the purpose of computing MEMS accelerometer scale and offset factors.
Which is why most people assume exactly 1 g for the purpose of computing MEMS accelerometer scale and offset factors.
- gammaburst
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Re: BNO085 Accelerometer Scale Factor
The BNO085 (and other similar inexpensive sensors) can easily detect variations of 0.7% of a g.
Take care using rigid words such as "exact", "cannot", and "fact".
A 0.7% error is acceptable for many applications, so your suggested inversion method of calibration would be adequate, and it's easy to do.
Take care using rigid words such as "exact", "cannot", and "fact".
A 0.7% error is acceptable for many applications, so your suggested inversion method of calibration would be adequate, and it's easy to do.
- sj_remington
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Re: BNO085 Accelerometer Scale Factor
Agreed!
When using the BNO085 to measure g at the North or South pole and at the top of Mt. Everest, one would certainly want to take those calibration considerations under advisement.
When using the BNO085 to measure g at the North or South pole and at the top of Mt. Everest, one would certainly want to take those calibration considerations under advisement.
Please be positive and constructive with your questions and comments.