Low g Accelerometer as a high frequency vibration sensor

[alisyed]

Is there an accelerometer in Freescale/NXP's low g series which can do high frequency vibration detection. I'm looking for something to mount on server hard drives (7200RPM - 12000 RPM) and the server chassis (for fans running between 0 - 24000RPM) which would provide continuous vibration reading (so I could dynamically set the threshold). I'd be using something like the MK20DX256VLH7 to interface with the sensor. Currently I'm trying to do this with an Arduino using a piezoelectric based vibration sensor. But you can't adjust those thresholds dynamically. I'd appreciate your help and suggestions on what product to use, and the best way to go about implementing it.

Thank you and best regards,

Ali

[david_diaz]

Hello Ali,

Please accept my apologies for the delay.

Indeed, FXLN8371QR1 and FXLN8372QR1 are recommended and both remain active.

The only difference between these is the Operating Range:

In regard with your second question, the only difference is the shipping type. The package is exactly the same.

I hope this information will be useful for you.

If I misunderstood your question, feel free to let me know.  I will be glad to help.

Have a great day.

David Diaz.

[alisyed]

david_diaz​

One other question I wanted to ask you is that what is the difference between MMA8451QT and MMA8451QR1? They look identical right down to the package.

Thank you again.

Best regards,

Ali

[david_diaz · Accepted solution]

Hello Ali,

The typical NXP low-g consumer accelerometers have a bandwidth response between 300 to 400 Hz at the -3 dB point. This indicates that the accelerometer can detect more than 400 Hz signals but it will be limited as the amplitude decays due to an internal low pass filter.

I personally recommend using the MMA8451Q -Low g, 14-bit Digital Accelerometer.

One of its typical application is the shock and vibration monitoring (mechatronic compensation, shipping and warranty usage logging).

Please find more information at:

MMA8451 ± 2g/4g/8g, Low g, 14-bit Accelerometer

Another recommendation would be the FXLS8471Q - Low g, 14-Bit Digital Accelerometer.

It is arguably the lowest noise digital part in the market with very good temperature performance, 14 bits of resolution and an ODR up to 800Hz.

You may find more information here:

FXLS8471Q ±2g/±4g/±8g, Low g, 14-Bit|NXP

In order to get a better understanding of the vibration and what would be the best way to measure it, you may refer to the following application note:

AN3751 - Frequency analysis in the industrial market using accelerometer sensors​

Also, there is an Application note related to the spectral estimation of vibration (acceleration), using the MMA955x that could be really useful for your costumer application, this app note includes the architecture of the mma9550L, mathematics of the DFT and their results from applying it to vibration, C codes examples, advantages and disadvantages of using DFT and FFT for this kind of application, etc.

AN4315 - Using the NXP MMA9550L for high resolution spectral estimation of vibration data

I hope this information will be useful for you.

If I misunderstood your question, feel free to let me know.  I will be glad to help.

Have a great day.

David Diaz.

Note: If this post answers your question, please click the Correct Answer button. Thank you!

[alisyed]

Hi David,

That’s excellent. Thank you for the information, and for all of the links. I’d like to ask, what’s your take on the FLN8371QR1, and FXLN8372QR1 sensors for this particular application. Do you think they’re viable options in addition to the options you’ve already provided?

I really appreciate your help.

Best regards,

Ali Syed

[david_diaz]

Hello Ali,

I am glad to help. I hope you find the links useful.

In regard with the FXLN8372QR1, I think it is an excellent option for your particular application:

The FXLN8372QR1 provides interface compatibility and simplicity for low-voltage MCUs, it has the best-in-class analog performance and it is part of the NXP Longevity Program.

You may find more information here​.

In case it is useful for you, you may find a bare metal example project here​.

Unlike the last recommendations, the FXLN8372QR1 is an analog-output accelerometer.

I am entirely at your service to answer your further questions.

Have a great day.

David Diaz.

Note: If this post answers your question, please click the Mark Correct button. Thank you!

[alisyed]

Hi David,

Thank you very much for all the information. The bare metal project is indeed helpful, as my own project will be bare metal, and it gives a good reference example. Since you mentioned the FXLN8372QR1 as a good choice, but not the FXLN8371QR1, I'm guessing the 71QR1 would not work for my application. Is this correct?

Again, I truly appreciate your help.

Best regards,

Ali