How to use the Microstack Accelerometer with Beaglebone Black

Question

Hi Guys!

I've tried to mount a Microstack Accelerometer on my new Beaglebone Black using the Program Matlab. (Sensor Technical Page Franell: Microstack Accelerometer Accessory Board).

First i had some Issues because there was missing a Jumper on the board so i couldn't get the I2C Adress of my Sensor (JP1-2 JP1-3).

Now that i managed to get the Adress and connect to my Sensor via I2C i am not able to get any right Data.

My Program in Matlab:

The Microstack Accelerometer has a MMA8491Q Xtrinsic 3-Axis Accelerometer on board ( http://cache.freescale.com/files/sensors/doc/data_sheet/MMA8491Q.pdf ) so it has 7 registers:

Every time i am reading (via I2C) the data from my Accelerometer i get this:

00000000

01010101

01010100

10101000

10011000

10101111

00010000

ZYXDR, ZDR, YDR or XDR are set 1 if the Data is ready.

So there is no change in Data , could anybody help me?

Former Member · Accepted Answer

I found out, that there are maybe different Versions of the Microstack Accelerometer. On the technical Page of Farnel of the Microstack Accelerometer is the Datasheet of the MMA8491Q Xtrinsic 3-Axis Accelerometer so I thought that this Chip is used.

However in the Python Code of the Mic.Acc. i found a Link to this Device: http://www.freescale.com/files/sensors/doc/data_sheet/MMA8452Q.pdf

So I used the wrong Datasheet...

clem57 · Answer

To prove this is good hardware wired correctly based on your assumptions, I would suggest to run this Python code from the manufacture directly.

https://github.com/microstack-IoT/python3-microstacknode/blob/master/examples/accel-angle-upright.py

If it works, the Matlab is missing something to set the EN pin on the board internally(?). If it does not workj, I would follow some hardware troubleshooting next.

Is that a plan?

Clem

How to use the Microstack Accelerometer with Beaglebone Black

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