Hi Mike,

Thanks for your answer.
Does it means that calibration of accelerometer is done when we "call
Mma_Accel.setSensitivity(RANGE)" ? Or only sensitivity is setted and I still
have to add my data an offset to reach the "physical values" ?

In the same idea, what exactly is displayed by the python script
SimpleAccel.py ? Coz I plotted it and it look quite awful even while I'm not
touching the accelerometer (I get kind of periodical +/- 10k to 35k peak). I
get better (it seems) results plotting Listen output and plotting separately
payload byte by two.
Does anybody know what DMA transfer exactly return (in terms of data) or
where I can find these informations (Didn't get it reading MMA7361
datasheet) ?

Once again, many thanks for help,
I can join plotting results I necessary.

Erwan.


2011/3/28 mike healy <[email protected]>

> Hi Erwan,
>
> The shimmer and shimmer2 used the MMA7260 accel chip, but the shimmer2r
> uses the newer MMA7361. See the following page for info on the different
> shimmer revisions:
> http://www.shimmer-research.com/products-2/shimmer-revisions
>
> One difference between the chips is that the MMA7260 had 4 different
> selectable sensitivity ranges (±1.5g, ±2g, ±4g and ±6g) whereas the MMA7361
> only has 2 (±1.5g and ±6g).
>
> The warning you are seeing about the decimal constant being too large has
> nothing to do with the sensitivity range, and can be safely ignored, as the
> intention is for the constant to be unsigned anyway.
>
> Mike
>
>
>
> On Mon, Mar 28, 2011 at 8:57 AM, Erwan RENAUDO <[email protected]>wrote:
>
>> Hi Mike,
>>
>> Thanks for your help.
>> I take a look at your program, and after several days have a "seems to
>> work" program. I take it example to make my serial sensor program working. I
>> get trunks of bytes that seems to change depending on my gestures. Now I'm
>> trying to analyse data and I would know about the accelerometer : in Shimmer
>> manual, they speak about MMA7260Q but when I check virtual component on
>> sources provided, accelerometer referenced is MMA7361. So which one is
>> physically present on the shimmer board, and could a bad platform argument
>> on compilation / wrong material virtualization generate warnings as "decimal
>> constant is so large that it is unsigned" (if wrong RANGE_X_0G is given) ?
>>
>>  Another question is : Is there a Linux XubunTOS calibration program as it
>> exists for Windows  ?
>>
>> Thanks for your answers and support,
>> Best regards,
>> Erwan
>>
>>
-- 
Élève Ingénieur Promo 2011 - Section *Informatique et Systèmes*.
École Nationale Supérieure de l'Électronique et de ses Applications (*
E.N.S.E.A.* - Cergy)
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