topic Re: 9 axis sensor in Sensors

9 axis sensor

a8Chcx — Mon, 20 Jul 2015 18:03:14 GMT

Hi,

I am going to develop my own 9 axis product for our mobile system. And I have the following question:

1) There are several 9-axies chip available on market, like ST, LSM9DS1, Invensense MPU-925X, and etc...Is there any 9-axis sensor from Freescale as well?

2) If not, which two chips that I can use to develop the same function as 9-axis chip?

3) If use two chips, is there any synchronization problem between accelerate and gyro sensor?

4) How about magnetic interference?

5) I am going to use K64F from Freescale, is there any development environment available to use?

Thanks,

Christie

Re: 9 axis sensor

michaelestanley — Mon, 20 Jul 2015 18:45:58 GMT

Christie,

I am happy to answer your questions. In order:

Freescale does not currently make a 9-axis device.
I recommend you use the FXOS8700CQ 6-axis (accel+mag) and FXAS21002 gyro.
There should be no problem with synchronization. Our sensor fusion typically samples the sensors at a 200Hz rate and runs the fusion at a 25Hz rate (both numbers are programmable). These rates are usually much above the physical bandwidth of the system we're modeling, and a few microseconds here and there has not been a problem.
The Sensor Fusion Library for Kinetis MCUs includes our award winning (yes, I'm bragging a little) magnetic calibration software. It supports a full 10-element hard/soft iron compensation.
The K64F is a fine platform for sensor fusion development. The toolkit includes an "out-of-box" build for that board. I would pair it with the new FRDM-FXS-MULTI2-B board. The sensor fusion toolkit supports both CodeWarrior and Kinetis Design Studio development environments. KDS is free, which is a nice selling point. I'll also mention that the most recent version of the Intelligent Sensing Framework (a graphical code generator) has integrated our sensor fusion as smart components that are easy to drop into your application. ISF is also free. The sensor fusion landing page includes a link to the Android version of the Sensor Fusion Toolbox, as well as the Windows-based development kit.

I would suggest you start by downloading the sensor fusion toolkit. It includes a full datasheet and user guide which should go a long way to get you started. Both predate the FXS-MULTI2-B board, but that board is backward compatible with the FXS-MULTI-B board, which is covered in detail.

Good luck and have fun!

Mike

Re: 9 axis sensor

a8Chcx — Wed, 22 Jul 2015 13:17:26 GMT

Hi Michael,

Thank you for your information.

I bought FRDM-FXS-MULTI2-B and downloaded Sensor Fusion Library for Kinetis MCUs .

I am using FREEDOM K64F platform, KDS 2.0.0 and KSDK 1.1.0 for my development.

Could you tell me these tools are OK for sensor fusion?

Are they supported by latest KDS 3.0.0 as well?

Thanks,

Christie

Re: 9 axis sensor

michaelestanley — Wed, 22 Jul 2015 15:34:15 GMT

Christie,

Your hardware is perfect. On that platform, you have two choices for how you develope sensor fusion apps. You can use the Sensor Fusion Library for Kinetis MCUs, which you have already downloaded. There is also a Processor Expert (P.E.) based implementation included in the latest versions of the Intelligent Sensing Framework (freescale.com/isf). The ISF version is somewhat less efficient (memory wise) than the Fusion Library, but perhaps easier for some people to use. The under-the-hood computations are the same. If you have NOT used Processor Expert, I would stick with the version you have. If you are a PE-expert, you may prefer the ISF version. Both will work fine on the K64F. I suggest you stick with KDS2.0 right now. I don't believe you need the KDSK at all, as the kit uses the older style logical device drivers (LDDs) for the serial interfaces. You will need MQXLite 1.1.1, which i believe should be part of your KDS installation.

We bundle a project for the K64F right in the kit. If it compiles and builds, you are good to go.

Regards,

Mike

Re: 9 axis sensor

a8Chcx — Wed, 22 Jul 2015 16:01:42 GMT

Hi Michael,

When I use my existing environment, I can compile and build the project successfully.

But, other project (Bootloader V1.2) requires KDS 3.0.0 to work with. So, I don't if you tried your project on KDS 3.0.0?

I am not sure if I can work on both KDS version on different project?

Thanks,

Christie

Re: 9 axis sensor

michaelestanley — Wed, 22 Jul 2015 16:38:38 GMT

Christie,

The current Sensor Fusion Toolkit was published when KDS 1.1 was still the hot new thing. You should be able to port the projects to KDS 3.0, but you need to be aware that there were some tool changes between KDS 2.0 and KDS 3.0. My friend Erich Styger did a nice summary of portability issues in a posting back in February. Look for the "Migration of KDS Projects" header, which shows some linker command changes you will need to make. I believe those comprise the major "gotcha", and it is otherwise a smooth process.

FYI #1: the Processor Expert-based version of sensor fusion does NOT yet support KDS 3.0.

FYI #2: You should be able to run multiple versions of KDS if you so choose.

Regards,

Mike

Re: 9 axis sensor

a8Chcx — Wed, 22 Jul 2015 16:53:39 GMT

Hi Michael,

Which version of KDS, KSDK or PE is supporting ISF?

Thanks,

Christie

Re: 9 axis sensor

michaelestanley — Wed, 22 Jul 2015 16:59:59 GMT

KDS 2.0 for the most recent ISF version.

Re: 9 axis sensor

a8Chcx — Wed, 22 Jul 2015 17:08:40 GMT

Hi Michael,

Thanks.

Based on your answers, the library that I downloaded from Web and worked with KDS2.0 is not based ISF, right? So, it will work with KDS3.0.0 and KSDK1.2.0?

I can use KDS 2.0 with PE to generate my own project that can be based on ISF?

Thanks,

Christie

Re: 9 axis sensor

michaelestanley — Wed, 22 Jul 2015 17:13:45 GMT

Yes. It is not based on ISF.

It should work with KDS 3.0.0 given the linker command changes I mentioned (although I'll admit I have not personally done that build).

I don't think you need KSDK at all.

And yes, you can use KDS 2.0 with ISF/PE.

The easiest way to confirm you are up and running is to simply install the executable you already built onto your K64F and try it with the Sensor Fusion Toolbox. One thing I will mention is that you need to select the UART in Processor Expert based upon whether you are using wired or wireless communications. Details are in the User Guide packaged with the kit.

Regards,

Mike