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SDK15 Invensense MPU9250

Hi, we switched from your competition to your platform. I know you wrote somewhere that you cannot provide examples for every sensor out there. But your Nordic Dev Zone is a bit messy, information cluttered everywhere. And soon, information is also outdated by your own updates.

If we would talk about motion sensors, I know there are like only two manufacturers: Invensense & Bosch.

Your competition has better community and also the owners themselves care more and provide basic examples on everything. I'm not asking you to do so. Just motion sensors, there is not many vendors and you have 50+ similar questions about motion sensors. It would be good, responsible, western EU style behavior, if your management would get some feedback from community managers. If so many people asking about issues or examples. You can have better ROI and save resources here, if you would, by all the years, provide some, even basic example. You have MPU in your documentation, but that does not stand for motion processing unit, it is some memory protection unit instead (only adds to confusion when googling).

We have met on CES at Las Vegas, you ask for some feedback, how to get better than competition. Your competition have better examples of how easy is to use their product. How good is time to market. Here I see only messy forum and customer rant about the same thing again & again and it is more than 1 year.

And before you will send here the unofficial Michael's github, I want to say that it was for SDK14. Not for SDK15. Next it does not use Invensense DMP driver.

I want to use eDMP motion driver by Invensense. Read quaternion (4D vector) and use their pipeline and configuration. Because, unlike Bosch with second ARM coprocessor, Invensense requires to load their driver in your firmware memory, in order to get these data. You can find many examples on Sparkfun, Adafruit, not to mention Arduino community itself. Also other ARM vendors provide at least one example.

I'm not asking you provide examples on every sensor out there. Just, when it comes to market share, there is only Invensense and Bosch with MPUs. That would be quite basic bluetooth beacon example in 2019.

So my question is: can I get SDK15 working with MPU9250 using DMP? On various boards including ESP, NXP, Arduino, it is really a matter of minutes and then companies, your customers, can focus on developing the product and time to market is acceptable. Here with Nordic, my experience so far, is that the community is not exchanging projects as it should and Nordic company is not doing anything to bring more customers on their platform. What took me one day on other platforms, is impossible to accomplis on SDK15.

I think it is start of 2019 and time to rethink this whole community / customer / startup / manufacturers strategy.

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  • Yes, I got experience with both Invensense and Bosch. I know in the past the Invensense library was, or still is, really buggy in terms of few constants off and all calculations are done on MCU. In the future might want to try to offload some calculations to the bluetooth host (for example smartphone). But from what I remember, Invensense put some raw hex encoded firmware setup that needs to be sent to MPU every time in order to access enhanced features. Also reading just acc or gyro is useless as it will drift over time, especially when you start turning 360 degrees several times. Not sure about the new ICM-20948, but Bosch have better and more open approach to this solution.

  • The new invensense INVN is better organized than the old MPL.  There are almost no docs about it.  

    Drifts will always be there, so you need to compensate for that.  I am not expert in fusion.  I only work in the low level driver.  Fusion algo is handle by someone else.  The Imu object class allows you to do exactly that, offloading algo or do it on chip and mixe and match sensor at will.  That's the beauty of C++ object design.  

  • Great! You are awesome! You save me for poor Nordic software development and (what is the opposite of best practices?). I will look into it today evening.

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