[Paparazzi-devel] Drotek imu calibration problem

[Chris]

Hi.
I got the Drotek imu to work ok with the twog but i have two problems.
1) The X axis seems to be reversed (towards the i2c signal pads and not 
according to the arrows
printed on the pcb)
I know that aspirin has this backwards but this is the 10df imu with the 
mpu6050 on I2C bus, who knows maybe it has the same flaw.

2) i tried to calibrate the accelerometer and what i got was not correct 
because the imu started to drift wildly.
Here is the console output:
address@hidden:~$ ~/paparazzi/sw/tools/calibration/calibrate.py 
-s ACCEL ~/paparazzi/var/logs/13_04_04__18_49_50.data
initial guess : avg 9.73738108474 std 0.0314174753141
optimized guess : avg 9.80993257151 std 0.0257190383087

<define name="ACCEL_X_NEUTRAL" value="61"/>
<define name="ACCEL_Y_NEUTRAL" value="6"/>
<define name="ACCEL_Z_NEUTRAL" value="-67"/>
<define name="ACCEL_X_SENS" value="4.87542830698" integer="16"/>
<define name="ACCEL_Y_SENS" value="4.89064537368" integer="16"/>
<define name="ACCEL_Z_SENS" value="4.81527520369" integer="16"/>

address@hidden:~$

And here is what i use for now which works ok:
    <!-- SENS = 2048 LSB/g / 9.81 ms2/g = 208.766564729 LSB/ms2 / 10bit 
FRAC: 1024 / 208.7665 -->
    <define name="ACCEL_X_SENS" value="9.81" integer="16"/>
    <define name="ACCEL_Y_SENS" value="9.81" integer="16"/>
    <define name="ACCEL_Z_SENS" value="9.81" integer="16"/>

Any ideas?
Chris