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3D RoboticsPermalink Reply by Chris Anderson on May 18, 2012 at 9:06am

Yes, we have the DMP running privately. It works very well, although not all that much better than a well-tuned DCM. The main advantage is that frees up processing power to do other stuff, like self-learning algorithms. Not a game-changer, but a nice thing to have. We're in production discussions with Invensense about releasing the necessary code open source and I hope we'll be the first to be able to do so. I hope to have more news in a few weeks. 

Permalink Reply by Farooq Niaz on May 18, 2012 at 9:18am

I think one should not expect much from a 15$ 6 in 1 chip as compared to costly (accurate) AD sensors. probably you can see some comments from timecop on this chip

Permalink Reply by Vernon Barry on May 18, 2012 at 9:53am

Sorry, this is a bit of a jump in thread, the original question I was answering:

Permalink Reply by Andke 2 hours ago

ouch - why do we do business with that company then ? - are they really that good

 

Who else makes the very sensors in a combined single chip solution? Exactly, they (Invensense) OWN the market on a combined sensor. This is why the APM 2.0 costs $199 and the older APM1.0 costs $250. The sensors and required support hardware drive the cost.

APM1.0 uses analog sensors and a separate A/D conversion chip thus driving up the cost and introducing several more points of error. A single chip solution that talks to the main processor via a single connection is far easier. They also own the proprietary code to run that chip in the very DPM mode they created.

I'm just trying to give you some background on the why it's used, and why it's a problem. Also, just a heads up it would not be way off to see some "export" laws thrown into the mix as to what can and cannot be opened to the public as source code. The US is very strict on code and software like this.

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Permalink Reply by Jake Stew on May 22, 2012 at 7:20am

ST makes an excellent Accel/Mag chip and a good gyro.  It's a 2 chip solution to get 9DOF either way you go.  Personally I would have gone with ST.  Invensense is a shitty company to deal with.

And as far as source code, the export issue was settled back in the late 90's.  See Bernstein v. United States.  Source code is 100% constitutionally protected free speech.  It's a shame the government was able to scare so many people into thinking they had to obey their bogus export control laws.  Nobody has ever been prosecuted for that sort of thing BTW.  Bernstein sued the government and won before they even tried to enforce anything.

He sued the gov. again when they rewrote the laws (still unconstitutional), but the judge threw out this case because he had no real standing since the gov. wasn't enforcing them or giving him any trouble.

So it would be no problem to release the DMP code.  The real issue is that 3DR probably didn't write any significant portion of it, so the code is still copyright by Invensense and covered by their disclosure agreement.

3DR should just rewrite the code instead of trying to deal with Invensense.  The code was given to them as example code so they really wouldn't have to change more than a tiny bit to call it their own.  I've never heard of any case where example code was the subject of a copyright lawsuit.  

In fact, it would be laughable to try and tell a judge that you're suing because your "example code" is the basis for a derivative work.  They'd laugh you right out of court.

So 3DR, release the code!  If you want, I can give you the number of a copyright lawyer.  Drop my name and I'm sure he'll give you some free advice (if he's not drunk).

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Permalink Reply by Andke on May 18, 2012 at 10:58am

Regarding my compass problem:

I've got another APM2 - replaced the GPS/SD/magnetometer board,  - and it works as expected.

So the failure is somewhere on my GPS/SD/mag board - but I verified all power & interface connections, without finding the error - the fact that SD *and* magnetometer fails on it - hints that it should be something they have in common.

Thanks to all who tried to help.

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