Author Topic: Are there non-contact vibration sensors for Arduino or PC?  (Read 2837 times)

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Offline engineheatTopic starter

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Are there non-contact vibration sensors for Arduino or PC?
« on: February 01, 2019, 03:47:11 am »
I need to sense vibration of an object, but I can't use accelerometers or piezo sensor because those requires touching the object, which is impractical in my application.

I hope to use an optic based approach, or any other method that can sense the degree of vibration without contact. I need to be able to feed the data into an Arduino or a PC.

I don't want to have to buy a big/expensive industrial type device. Size and price matters. However, I can place the sensor very close (millimeters) to the object. Any ideas?

thanks
 

Offline MavMitchell

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Re: Are there non-contact vibration sensors for Arduino or PC?
« Reply #1 on: February 01, 2019, 03:59:56 am »
Any idea of the frequency and amplitude of the vibration. Is the body metal..
 

Offline jazper

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Re: Are there non-contact vibration sensors for Arduino or PC?
« Reply #2 on: February 01, 2019, 06:34:22 am »
Frequency and amplitude matter..

accelerometers on a membrane could work (think a speaker cone)

A microphone could work depending on frequency.. or ultrasonics if the amplitude is high..
 


Offline David Hess

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Re: Are there non-contact vibration sensors for Arduino or PC?
« Reply #4 on: February 01, 2019, 02:54:40 pm »
Optical interferometry can be used to remotely measure vibration.  Capacitance sensing could also work which means reluctance sensing is a possibility also.
 

Offline Dundarave

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Re: Are there non-contact vibration sensors for Arduino or PC?
« Reply #5 on: February 02, 2019, 07:08:28 am »
I understand that spy-types have been using a laser beam against plate glass windows for years, and demodulating the reflected light.

It might be as simple as lining up an infrared LED and a receiver beside each other facing the target (so the LED and IR receiver don't see each other directly), and then sending a kHz signal via the LED and piping the IR receiver and a copy of the transmission into a differential op amp to get the difference.

That would be interesting (and pretty easy) to experiment with.
 

Offline ebastler

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Re: Are there non-contact vibration sensors for Arduino or PC?
« Reply #6 on: February 02, 2019, 08:05:59 am »
Microphones have been used successfully.  ;)

But as others have said: The question is somewhat meaningless without indicating the frequency and amplitude range, and the properties of the vibrating object (size, mass, surface properties).
 

Offline engineheatTopic starter

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Re: Are there non-contact vibration sensors for Arduino or PC?
« Reply #7 on: September 06, 2019, 07:45:03 pm »
Okay, I tested with microphone. It didn't work well due to the ambient noise.

The object that I want to measure vibration is an electric shaver. The FFT of the recorded sound shows a maximum frequency of interest of around 5khz (above which I'm not too interested).

I don't think the laser doppler vibrometers would be within my budget (less than $1k).

Now I'm looking into contact piezo sensors/accelerometers. Having never used them, I wonder if the force of contact between the sensor and the object is a key attribute I need to control. I'm thinking about using a magnet to attach the sensor to the object.

This one here seems like something cheap and easy to experiment with:
https://www.tindie.com/products/electromake/3-axis-usb-accelerometer/

but it seems the max frequency is only 3000hz. Is this the sampling rate?

Thanks
 

Offline Brumby

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Re: Are there non-contact vibration sensors for Arduino or PC?
« Reply #8 on: September 08, 2019, 10:41:45 am »
but it seems the max frequency is only 3000hz. Is this the sampling rate?

The answer is in the specification:

AVAILABLE COMMANDS
Here is a list of commands that you can send to the accelerometer dongle. You can control the frequency of data sampling, the range of measured acceleration and stop/start streaming data. This dongle has an LED to indicate if the acceleration is measured and how fast it is measured. It also has an LED power indicator.

STOP - Stops accelerometer data streaming.

START - Starts accelerometer data streaming.

FREQ frequency - Changes acceleration data sampling frequency.

Available frequency values in hertz are: 3200, 1600, 800, 400, 200, 100, 50, 25, 12.5, 6.25, 3.13, 1.56, 0.78, 0.39, 0.2, 0.1.
 

Offline kosine

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Re: Are there non-contact vibration sensors for Arduino or PC?
« Reply #9 on: September 08, 2019, 12:32:01 pm »
Would a linear hall effect sensor work?

SS49E datasheet says response time of 3us, so sampling rate would be adequate.

https://sensing.honeywell.com/honeywell-sensing-ss39et-ss49e-ss59et-product-sheet-005850-3-en.pdf
 

Offline DTJ

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Re: Are there non-contact vibration sensors for Arduino or PC?
« Reply #10 on: September 08, 2019, 01:06:23 pm »
Do you have a moving metal target on the shaver?

Use an oscillator with a lossy coil to sense the moving metal.

http://www.kamansensors.com/  used to make them 20 years ago,  I guess they still do.


You can make one with a transistor, some caps and a coil & send the output to a CRO.




 

Offline ddavidebor

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Re: Are there non-contact vibration sensors for Arduino or PC?
« Reply #11 on: September 08, 2019, 01:24:20 pm »
You can also use a doppler radar to measure vibration, there are articles about it, but it's not simple.
David - Professional Engineer - Medical Devices and Tablet Computers at Smartbox AT
Side businesses: Altium Industry Expert writer, http://fermium.ltd.uk (Scientific Equiment), http://chinesecleavers.co.uk (Cutlery),
 

Offline Dundarave

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Re: Are there non-contact vibration sensors for Arduino or PC?
« Reply #12 on: September 09, 2019, 01:24:23 am »
If you can get within a few millimetres of the electric razor's moving blade (assuming that the blade contains steel), then perhaps a simple coil similar in design to an electric guitar pickup might be all you need. 

Essentially a variable-reluctance sensor, you could wind a quick-and-dirty coil around a magnetized iron nail and see what the output looks like when you hold the head of the nail (i.e. the coil perpendicular) near to the moving blade...
« Last Edit: September 09, 2019, 01:30:45 am by Dundarave »
 

Offline engineheatTopic starter

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Re: Are there non-contact vibration sensors for Arduino or PC?
« Reply #13 on: September 09, 2019, 04:47:31 am »
but it seems the max frequency is only 3000hz. Is this the sampling rate?

The answer is in the specification:

AVAILABLE COMMANDS
Here is a list of commands that you can send to the accelerometer dongle. You can control the frequency of data sampling, the range of measured acceleration and stop/start streaming data. This dongle has an LED to indicate if the acceleration is measured and how fast it is measured. It also has an LED power indicator.

STOP - Stops accelerometer data streaming.

START - Starts accelerometer data streaming.

FREQ frequency - Changes acceleration data sampling frequency.

Available frequency values in hertz are: 3200, 1600, 800, 400, 200, 100, 50, 25, 12.5, 6.25, 3.13, 1.56, 0.78, 0.39, 0.2, 0.1.


A max data sampling freq of 3200 is not enough to sense vibration 5khz or above right? I assume an object that creates a 5khz sound is also vibrating at 5khz.

 

Offline engineheatTopic starter

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Re: Are there non-contact vibration sensors for Arduino or PC?
« Reply #14 on: September 09, 2019, 04:50:56 am »
Would a linear hall effect sensor work?

SS49E datasheet says response time of 3us, so sampling rate would be adequate.

https://sensing.honeywell.com/honeywell-sensing-ss39et-ss49e-ss59et-product-sheet-005850-3-en.pdf

I'm not familiar with hall effect sensors. How would it work for my project?
thanks
 

Offline Brumby

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Re: Are there non-contact vibration sensors for Arduino or PC?
« Reply #15 on: September 09, 2019, 05:42:47 am »
A max data sampling freq of 3200 is not enough to sense vibration 5khz or above right? I assume an object that creates a 5khz sound is also vibrating at 5khz.

Using Nyquist, a 3.2kHz sampling rate will be able to handle frequencies up to 1.6kHz - but that does not mean a 3.2kHz sampling rate won't pick up something from a 5kHz vibration.  You won't be able to reproduce the 5kHz waveform, but you might get something you could use.

At this point, however, I will defer to those who can speak with more authority on such a subject.
 

Offline ddavidebor

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Re: Are there non-contact vibration sensors for Arduino or PC?
« Reply #16 on: September 10, 2019, 06:21:11 am »
Would a linear hall effect sensor work?

SS49E datasheet says response time of 3us, so sampling rate would be adequate.

https://sensing.honeywell.com/honeywell-sensing-ss39et-ss49e-ss59et-product-sheet-005850-3-en.pdf

I'm not familiar with hall effect sensors. How would it work for my project?
thanks

You put a magnet somewhere, a hall sensors somewhere else in close proximity. Magnetic field varies and so does the hall sensor output that measures magnetic fields.

David - Professional Engineer - Medical Devices and Tablet Computers at Smartbox AT
Side businesses: Altium Industry Expert writer, http://fermium.ltd.uk (Scientific Equiment), http://chinesecleavers.co.uk (Cutlery),
 


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