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View Full Version : Re: - 3D Accelerometers



Stuart O Anderson
05-14-2008, 12:32 AM
Kat -

With regard to accelerometer selection, and in particular the
analogdevices products, you should be aware that many do not give you
a raw signal. Rather, they have rather aggressive low pass filters
applied to the signal before you can get to it. This introduces phase
lags at higher frequencies that can be really annoying in a controls
context and may be relevant if you're looking at data from impacts.
More expensive gyros and accelerometers use even more complex
filtering (usually a Kalman variant, I think).

Stuart

On Tue, May 13, 2008 at 3:51 PM, wrote:
> Dear Kat,
>
> 1st - I fully support Chris that one could and should build his own device
> and one will benefit a lot just from this step.
>
> 2nd - if you really want to buy 'stuff' I may suggest a system that consists
> of an accelerometer (I used PCB) with power module attached to a Compact
> flash card from NI that is inserted in the Pocket PC (i.e. Axim - 51 Dell).
> This system worked fine for me.
>
> Arkady
>
> Quoting Chris Kirtley :
>
>> Dear Kat,
>>
>> My opinion is that people are too lazy these days - and for no justifiable
>> reason, since it is so easy to build your own circuits now.
>>
>> You can buy a 3D accelerometer chip for about $10 and build a nice
>> microcontroller around it, with flash memory and maybe Bluetooth
>> telemetry,
>> for not much more. In doing so you will get a much more versatile tool
>> and,
>> more importantly, will understand every step of how you obtain the data.
>> This is what universities are for - designing and building instruments -
>> not
>> buying off-the-shelf products.
>>
>> I would be interested in what others think!
>>
>> Chris
>>
>> On Mon, May 12, 2008 at 10:48 PM, Kat Arbour wrote:
>>
>>>
>>> >
>>> Hi All-
>>>
>>> I am planning to research the landing accelerations of various high
>>> impact
>>> jumping skills in an athletic population. Biometrics LTD (Model ACL300)
>>> has
>>> an accelerometer that may be perfect for what I am looking for. The
>>> accelerometer wires to the datalogger, worn on the back, then the athlete
>>> is
>>> free to do whatever, where ever. (It measures acceleration
>>> impact-by-impact
>>> , its not an "activity monitor" for daily caloric expenditure). I am
>>> inquiring to see if anyone is familiar with the accelerometer and has an
>>> opinion about its performance. If you have used it in your research, I
>>> am
>>> very interested in your experiences with it. If you have used different
>>> accelerometers that allows the subject to be untethered, that would be
>>> great
>>> information, too.
>>>
>>> Thanks for sharing!
>>>
>>>
>>> Kat Arbour MS MPT
>>> PhD student
>>> Biomechanics and Movement Science
>>> University of Delaware
>>> Newark, DE 19716
>>>
>>>
>>>
>>> ---------------------------------------------------------------
>>> Information about BIOMCH-L:
>>> http://www.Biomch-L.org
>>> Archives: http://listserv.surfnet.nl/archives/Biomch-L.html
>>> ---------------------------------------------------------------
>>>
>>
>>
>>
>> --
>> Dr. Chris Kirtley MB ChB, PhD
>> 608 Dockside
>> 44 Ferry St.
>> Kangaroo Point
>> Queensland 4169
>> Australia (GMT+10)
>> Tel. 61+7-3891 6644 x 1608
>> Fax 3891 6900
>>
>> West End Family Medical Centre
>> Mondays, Tuesdays & Thursday afternoon (07) 3844 4111
>>
>> Clinical Gait Analysis: http://www.univie.ac.at/cga
>> Book:
>> http://www.amazon.co.uk/exec/obidos/ASIN/0443100098/203-6674734-4427132
>>
>>
>>
>> --
>> Dr. Chris Kirtley MB ChB, PhD
>> 608 Dockside
>> 44 Ferry St.
>> Kangaroo Point
>> Queensland 4169
>> Australia (GMT+10)
>> Tel. 61+7-3891 6644 x 1608
>> Fax 3891 6900
>>
>> West End Family Medical Centre
>> Mondays, Tuesdays & Thursday afternoon (07) 3844 4111
>>
>> Clinical Gait Analysis: http://www.univie.ac.at/cga
>> Book:
>> http://www.amazon.co.uk/exec/obidos/ASIN/0443100098/203-6674734-4427132
>>
>> ---------------------------------------------------------------
>> Information about BIOMCH-L: http://www.Biomch-L.org
>> Archives: http://listserv.surfnet.nl/archives/Biomch-L.html
>> ---------------------------------------------------------------
>>
>
>
>
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