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[on:]

Hi,
    I am new to arduino, I am having fun though in between frustrations.
I need some help with an ADXL335,
I have set up an ADXL335 on a bread board in the hope of one day measuring vibration of a bearing using an uno.
Just to experiment, I have dowloaded the code for the ADXL335 from the arduino site just to experiment.
i have also wired as per drawing except connected VCC to 3.3V terminal, Laying the breadboard flat and the axdl335 flat on top.
On the serial monitor i get the following readings;

x               y              z
350      344      838
350      344      838
350      344      838
350      344      838
350      344      838
350      344      838
350      344      838
350      344      838
349      344      838
350      343      838

as i move the board around, up and down etc;  the values change on x and y approximately +/- 50.

z changes about +/- 10.

i will eventually use an average calculation to smooth out the readings.

Why is the Z reading so High and not flucuating as much and is it possible to measure vibration?

Or is there another way to measure bearing vibration?

Before anyone asks, I tried a piezo sensor with not much success due to sensitivity.

Cheers

[Reply #1 on:]

http://www.analog.com/static/imported-files/data_sheets/ADXL335.pdf

It can measure the static acceleration of gravity in tilt-sensing applications, as well as dynamic acceleration resulting from motion, shock, or vibration.

So, yes, measuring vibration is possible.

The user selects the bandwidth of the accelerometer using the CX, CY, and CZ capacitors at the XOUT, YOUT, and ZOUT pins.

So, one would suppose then that the different steady-state readings reflect different capacitors for the different axes.

Posting a link to the particular device you have might be a good idea.

[Reply #2 on:]

Why is the Z reading so High

Because, where you are, gravity is working downwards.

[Reply #3 on:]

Sorry PaulS,
                 I tried to put link in message but it said i couldn't when its my first post. ( yes i am virgin!)
this is the unit i have purchased.
Hopefully this works,
http://toysdownunder.com/triple-axis-accelerometer-breakout-adxl335.html
It seems it already has 0.1uf capacitors installed according to the schematic.

Cheers