the 9DOF calibration utility applies an alignment matrix to the decimal output (along with the scale factors and offsets). The alignment matrix contains axis order and sign, as well as any non-orthogonal corrections. JustFATLogging just outputs the decimal data as is, as far as i am aware, so you would need to apply the calibration coefficients to gain calibrated output with the correct axis order/sign. Take a look at the Calibration Utility manual. Chris
Date: Thu, 30 Aug 2012 07:17:18 -0700 From: [email protected] To: [email protected] Subject: [Shimmer-users] JustFATLoggin axes vs Shimmer 9DOF I've modified JustFATLogging and the Shimmer provided MATLAB code to collect Gyro readings. I added the Gyro using: call GyroInit.init(); call GyroStdControl.start(); call shimmerAnalogSetup.addGyroInputs(); For debugging I decided to compare the data collected by JustFATLogging and Shimmer's 9DOF Calibration utility. It seems that when I position the Shimmer on its face (logo side) JustFATLogging thinks that it is the -Z acceleration axis (9DOF correctly shows that it is the +Z). When I check the gyro is seems that JustFATLogging and 9DOF do not agree on which is the X and which is the Y axis. In MATLAB I am reading the data by: sensorsData = fread(fid, [NUMBER_OF_CHANNELS,Inf], 'uint16'); accelx = sensorsData(1,:); accely = sensorsData(2,:); accelz = sensorsData(3,:); gyrox = sensorsData(4,:); gyroy = sensorsData(5,:); gyroz = sensorsData(6,:); What am I doing wrong? Thanks, Rahav Rahav Dor _______________________________________________ Shimmer-users mailing list [email protected] https://lists.eecs.harvard.edu/mailman/listinfo/shimmer-users
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