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Topic: How to connect 3-Axis Accelerometer Sensor MMA7260 (Read 2410 times) previous topic - next topic

WEBAFF

May 25, 2011, 06:35 pm Last Edit: May 25, 2011, 06:53 pm by WEBAFF Reason: 1
I have an accelerometer MMA7260 from Ebay and I trying to connect it to arduino by this scheme:



I use a simple sketch which serial.println (analogread (0)) and i get this strange random dataset:
232
482
248
584
but the sensor is fixed and not moving. I thought data should like be VALUE -+ 20 error, not +- 300 error.

Maybe I'm using the wrong scheme? Anyone used this module, is it ok?

Schematic
http://www.b2cqshop.com/best/MMA7260QT.pdf

RuggedCircuits

I don't see a schematic of your board, but it doesn't look like there is any regulator on there, so instead of connecting 5V to Vin try connecting 3.3V to Vin (unless the accelerometer has already been damaged by 5V :(   )

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WEBAFF

#2
May 25, 2011, 06:57 pm Last Edit: May 25, 2011, 07:01 pm by WEBAFF Reason: 1
I uploaded a schematic picture to another site. Which voltage i should connect to SL pin on Accelerometer?

Also, here some scheme from ebay seller:


RuggedCircuits

OK, it looks like it does have a regulator (on the bottom). So you have it hooked up right. 3.3V is the right voltage to put on the SL pin.

Sorry, don't know what's wrong then. Do you have very long wires between the module and the Arduino; they may be picking up noise. It's also common to filter out the X/Y/Z outputs with small caps and resistors. It looks like there are resistors on the board but no caps. See Figure 6 in the MMA7260 datasheet.

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wayneft

Quote
It's also common to filter out the X/Y/Z outputs with small caps and resistors.

I would look into this first.  Do you have a 0.1uf ceramic disc cap laying around that you can put on the output axis to see if it makes a difference?
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