What's the unit of Nicla's acceleration sensor?

I need to get acceleration value in m/s^2 or in gravity but I can't find any information about the quite high values I get from the sensor even in "rest mode". I need to measure vibrations and the Nicla seems like a perfect fit.

I have read the Getting started and played around with standalone.ino. I have tried both SENSOR_ID_LACC and SENSOR_ID_ACC. Any other out there using the Accelerometer?

And the sketch is found in the cheat sheet: docs.arduino.cc/tutorials/nicla-sense-me/cheat-sheet

Please provide links to the sensor data sheet and to the sketch that you mention. Don't make potential helpers search for stuff that you have ready access to.

The sensor measures the acceleration due to gravity, in addition to those accelerations caused by other forces. The units of measurement are described in the data sheet.

What range of vibration are you trying to measures?

Are you aware this sensor measures static acceleration? i.e. how fast is your Prius accelerating down the drag strip.

What range of vibration are you trying to measures?

0-500Hz

Are you aware this sensor measures static acceleration? i.e. how fast is your Prius accelerating down the drag strip.

Yes but isn't a vibration acceleration in two opposite directions?

Why? It has a steep learning curve and countless functions that you don't need to measure vibrations.

Any accelerometer with ODR > 1000 Hz can be used to detect vibration with frequency up to 500 Hz.

Size is one big upside here. Plus all other functionality I need with battery charger, BLE etc.

Great! Let us know when you get it working.

Mathematically yes. But to measure 500 Hz you would have to sample at at least 10x the vibration frequency. Assume a sinewave vibration. At the peak(s) of the sinewave, the acceleration is 0, conversely at the zero crossover the acceleration is at maximum.

So at 500 Hz, the full cycle is 2 ms. Your sensor can only read at about 500 ms. Even if the sensor could "average" the full sine acceleration, the result would be 0.

Hi, @rolf2
Welcome to the forum.

Google;

arduino vibration sensor

This may help;

Tom... :smiley: :+1: :coffee: :australia:

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Thank you @TomGeorge ,

I have googled a lot to find out what the values the virtual accel. sensor's are giving me but have not really find some answers on that. Are now comparing readings with other sensors to reverse engineer the values. Right now it looks like Standard gravity which I can take x 0.101972 to get m/s^2 but I need to confirm it.

As stated in reply #3, everything of interest is in the data sheet that you linked.

Page 97 states:

For the RAW accelerometer data , the following applies (p. 149):

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When we were doing vibration testing we used a Piezo charge coupled sensor with (for a professional application) has a significant $$$$ electronic unit. There were some less expensive but still not hobby level.

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Thank you! Then it it Standard gravity that I need to convert to m/s^2 by multiplying with 0.101972.

Do I need to consider the 2, 4, 8, 16 part or are they just a label on the symbol?

I've read all docs for hours, not realising it was that "simple".

Hi,

One Standard Gravity = 9.81 m/s^2 when I went to school.

Tom.... :smiley: :+1: :coffee: :australia:

One Standard Gravity = 9.81 m/s^2 when I went to school.

Yes you're right - I read the conversion table wrong.