Help!! Directions definition and a wired reading of ArduIMU Ver2

Many thanks in advance for any suggestion and experience first.


Need help on the following two issues:


1. Can someone confirm with me the directions definition of ArduIMU Ver2? Accroding to the mark at the bottom, the ArduIMU Ver2 follows right-hand rule. However, suprisingly, when I do the test, I found that all the definitions are opposite (i.e., from the top view, backward and left are positive. for z direction, up is position). Furthermore, when I check the eagle file, I found two set of direction definitions marked.


2. I intentionally put the IMU with a phical roll angle of 90-degee and power it on. I expect to read a close-to-g value along y directions. However, it turns out the reading is still:

    x -- near to 0;

    y -- near to 0;

    z -- near to g.

    Can someone explain it briefly to me?


Again, many thanks for helping me out.



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I don't know about the silkscreen, but what code are you running?

The code version is 1.6.


Does it affect the direction definitions?


Thanks, Chris.



When I first received my IMU I used the demonstration program to display pitch, roll, and yaw. To the best of my knowledge the cube followed the physical pitch, roll, and yaw of the board.





    Thanks, man, for your information.

    Actually the roll, pitch, yaw is with correct defination, I mean, following the right-hand rule. It also suprises me since the acc does not follow it.


    A small update: code ver 1.6. I have been testing it using the HKM demo for serveral times and found that the recorded acc is indeed with oppsite positive definitions (back, right, and up are positive). Just wanna see whether some friends here can confirm it with me or, better, correct me if I were wrong.






It's all determined by the code. ArduIMU now uses the APM libraries, and we may use a different frame of reference on that, as opposed to the original ArduIMU demo. The silkscreen on the board is overruled by the software.

I'm not sure why it matters. Just orient the IMU the way the software wants and all should be well, no?

Thanks, Chris.


The main reason I need the confirmation is that now I am using a self-modified code in the ArduIMU ver2, which is based on 1.6 ver code and the servo reading function (inspired by Julio's Quad II mini code) is included. So can not upgrade to 1.8 ver right now.


But I think I rough get my answer and what I need to do is to chance the signs to those I expect.


Thank to both

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