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Unread 07-02-2005, 10:07
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Question Re: Example gyro code released.

Quote:
Originally Posted by Kevin Watson
Has anyone tried this code yet? I'd like to get a sense of how (if) it's working for teams.

-Kevin
Kevin,
I have tried the ADXRS300EB and the BEI gyrochip AQRS-0075-xxx
(two different units) with some problems.
I have measured a nominal 2.5 volts for both sensors and when
physically swinging both gryo's in opposite directions see the voltage
swing up/down as expected. So, from a gross standpoint, gyro's are
operational.
The software outputs a gyro bias of 4144? When, I swing the
gryo 180 degrees in one direction, slowly, and return to zero I cannot
get the gyro to indicate zero.
Have set #define to ADXRS300EB setting and #define to AQRS0075
and played with scaling factor without success.
Turned out long term Bias calculation - close to short term bias.
After powering up and gyro reading 0 degrees for 4 or 5 samples,
I swing the gryo 180 degrees slowly and return to zero.
Any suggestions, Kevin.

BTW, I really believe the ADXRS300 EB scaling is not 5 mv /degree/sec
but 7.5 mV/degree/sec. Plus/minus 300 degrees over 4.5 volt range,
is 300 degrees over 2.25 volt range (2.5 to 4.75 or 2.5 to 0.25 volts).
or 2250 mV/300 degrees which is 7.5 mV/deg.

Scaling for Plus/Minus 75 degrees/ second is 30 mV/deg/sec
Scaling for Plus/Minus 150 degrees/second is 15 mV/deg/sec
scaling for plus/minus 300 degrees/second is 7.5 mV/deg/sec
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