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Accelerometers

Holmz

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This is probably the wrong sub forum… but what do people use for harmonics and resonance measurements?
I found a Slam-Stick accelerometer, ($1500-$1800) and a bunch of lower frequency Arduino-based solutions, as well as expensive B&K equipment.

I think that I need something that goes to 1000Hz or more… so 2k sampling or more.

Are there some relatively affordable solutions?

My intent is to bring in the data through the sound card to digitise it.
 

NTK

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Some of the Arduino type cheap accelerometer boards based on the Analog Device ADXL335 from Sparkfun or Adafruit or even the eval boards from Analog Devices have bandwidth to 1 kHz. However, you'll need to replace the capacitors on the boards. They usually come with 0.1 μF capacitors to set the bandwidth to 50 Hz. You'll need to desolder them and replace with the minimum recommended value of 0.0047 μF to increase the bandwidth to 1 kHz.


ADXL335.PNG
 

thewas

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I think that I need something that goes to 1000Hz or more… so 2k sampling or more.

Are there some relatively affordable solutions?
Keep in mind that the higher you go up in frequency the higher is the influence of the accelerometers mass on the attached structure, so it should be as small as possible.
Unfortunately I don't know of cheap solutions as I used in the past only ones from B&K and PCB, the second ones usually quite cheaper though http://www.pcb.com/sensors-for-test-measurement/accelerometers
Also beware that ICP sensors need a specific voltage from the measuring device https://www.pcb.com/resources/technical-information/introduction-to-accelerometers
 
OP
Holmz

Holmz

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Ordered!
Thanks @NTK

Keep in mind that the higher you go up in frequency the higher is the influence of the accelerometers mass on the attached structure, so it should be as small as possible.
Unfortunately I don't know of cheap solutions as I used in the past only ones from B&K and PCB, the second ones usually quite cheaper though http://www.pcb.com/sensors-for-test-measurement/accelerometers
Also beware that ICP sensors need a specific voltage from the measuring device https://www.pcb.com/resources/technical-information/introduction-to-accelerometers
Yeah @thewas - but it is for testing a wooden plank as a table top.
And then testing a similar dimension as a laminate of wood and constrained damping layers.

Pretty much like the endless debates about isolation feet and microphonics… So maybe I am moving into a group that thinks it could make a difference?

Hence it is not so much about the specific frequency, as it is in just lowering the “Q” of the furniture.
 

Blumlein 88

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If it's just for one off testing, can you use the one in a cell phone? Or maybe one of those piezo pickups people use on acoustic guitars.
 

puppet

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I'd try a simple half full cup of water/coffee. Watch the ripples and match with specific frequency.
 

Blumlein 88

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I'd try a simple half full cup of water/coffee. Watch the ripples and match with specific frequency.
This works too. I've used this, but shine a tight flashlight beam on it. Angle so the reflection travels across the room onto the wall most far away. This acts like a lever amplifying movement making it easy to see.
 

AdamG247

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