Hi everyone,

I want to measure vibration with my XDK

i just wondering how I use the FTT function from the Bosch Toolbox.

 

Have someone did this before?

Thanks

Stephan

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RE: How to use FFT (Fast Fourier Transform) from Toolbox for measure vibrat
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17. 3. 8 오후 4:09 as a reply to Stephan Funk.

Hello Stephan,

the FFT is included in many algorithms of the Bosch Toolbox.

In many cases it is not needed to compute the FFT directly and it is sufficient to access the sensors on high level APIs which are much easier to use.

Would you be so kind and get more into detail about how you want to measure the vibration and what output values you are expecting.

Kind regards,
Franjo

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RE: How to use FFT (Fast Fourier Transform) from Toolbox for measure vibrat
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17. 3. 10 오후 5:35 as a reply to Franjo Stjepandic.

Hello Franjo,

in my case I need to get the frequency in Hz.

I didn´t find any information about this, so I´m wondering if it´s possible.

Regards,

Stephan

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RE: How to use FFT (Fast Fourier Transform) from Toolbox for measure vibrat
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17. 3. 10 오후 5:53 as a reply to Stephan Funk.
Hi Stephan, as a suggestion.

You can also add your own implementantion of the FFT, there is a open source suitable for M3 cores FFT called fix_fft, I have been used it for 2 years and works great you will need only a iterator to your samples to compute the complex magnitude operation.

I used the implementation on a previous project, but you can of course reuse on XDK, I will start to optimize this FFT in order to get better performance when running in a CM3:

https://github.com/uLipe/psoc_engine_sensor/blob/master/engine_speed_sensor.cydsn/fix_fft.c


I hope it helps you.

Best 
Felipe
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RE: How to use FFT (Fast Fourier Transform) from Toolbox for measure vibrat
응답
17. 3. 10 오후 5:53 as a reply to Stephan Funk.
Hi Stephan, as a suggestion.

You can also add your own implementantion of the FFT, there is a open source suitable for M3 cores FFT called fix_fft, I have been used it for 2 years and works great you will need only a iterator to your samples to compute the complex magnitude operation.

I used the implementation on a previous project, but you can of course reuse on XDK, I will start to optimize this FFT in order to get better performance when running in a CM3:

https://github.com/uLipe/psoc_engine_sensor/blob/master/engine_speed_sensor.cydsn/fix_fft.c


I hope it helps you.

Best 
Felipe
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RE: How to use FFT (Fast Fourier Transform) from Toolbox for measure vibrat
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17. 3. 10 오후 7:02 as a reply to Felipe Neves.

Hi Felipe, 

thanks for your fast reply.

 

Your Link don't work:(

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RE: How to use FFT (Fast Fourier Transform) from Toolbox for measure vibrat
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17. 3. 10 오후 7:52 as a reply to Stephan Funk.

I uploaded a picture from the Datasheet.

 

So there must be a function with the complete fft library or somthing like that, but i can't find them.

 

How can i use this ''toolbox''?

 

Stephan

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RE: How to use FFT (Fast Fourier Transform) from Toolbox for measure vibrat
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17. 3. 13 오후 5:33 as a reply to Stephan Funk.

Hello Stephan,

there is indeed a complete library (toolbox, in other words) with the FFT functionality.
This library is located in the low level API of the EFM32GG micro controller of the XDK. You can navigate to the library arm_math.h by using the following folder path:

SDK > xdk110 > Libraries > EMLib > CMSIS > Include

The FFT functionality you are searching for starts at line 1960. You should find all necessary information there that you need to use the FFT in your own application.

Additionally thanks to Felipe by providing a source for a custom implementation of the FFT. This is also a possible solution, of course.

Please tell me if this is helpful and do not hesitate to ask if you have further questions.

Kind regards,
Franjo

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RE: How to use FFT (Fast Fourier Transform) from Toolbox for measure vibrat
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17. 3. 14 오후 10:09 as a reply to Franjo Stjepandic.

Thanks Very much,

That looks good!

I really appreciate your help!

 

I will try it out!

Thanks

 

Regards

 

Stephan

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RE: How to use FFT (Fast Fourier Transform) from Toolbox for measure vibrat
응답
17. 3. 15 오후 5:32 as a reply to Stephan Funk.

Hello Stephan,

I am glad that I could help.

Please do not hesitate to ask if you have further questions.

Kind regards,
Franjo

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