View Full Version : Re: - 3D Accelerometers

05-13-2008, 05:05 PM
Let me strongly endorse Sparkfun! For all that Chris and Ton say you
really don't want to be soldering the raw chips. These are all
leadless devices designed to be float soldered and soldering them by
hand is pretty tricky (believe me, I've done it). Sparkfun sell the
same chips mounted on small breakout boards which are *MUCH* easier to
deal with and well worth the extra $20. I notice they've just released
a complete wireless 3D accelerometer module (WiTilt v3.0) for $300 -
still very cheap compared to what you'd pay for a wireless device.
There are other companies out there that specialise in the robotics/
model building market that provide similarly inexpensive items.

There is a caveat here though. Depending on your local ethics board
you may more difficulty persuading them to let you attach lab built
devices to people particularly if they are connected via a lead to a
computer without isolation. Battery powered wireless devices should
not be a problem though. In a clinical setting presumably you have to
use commercial, licensed and tested products whatever (and perhaps
that's the justification for why biomechanics badged equipment is
often much more expensive than equivalent engineering products).

Dr. Bill Sellers Email: William.Sellers@manchester.ac.uk
Lecturer in Integrative Vertebrate Biology Skype: wisellers
Faculty of Life Sciences Tel. 0161 2751719
The University of Manchester Fax: 0161 2753938
Jackson's Mill, PO Box 88 Mob: 0785 7655786
Sackville Street, Manchester, M60 1QD, UK http://homepage.mac.com/wis/ASL/

On 14 May 2008, at 01:33, van den Bogert, Ton wrote:

> Chris Kirtley wrote:
>> 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.
> I totally agree. Some more information (for the archives):
> Chips are available from http://www.analogdevices.com (iMEMS
> accelerometers) and they are indeed about $10 for a 3D accelerometer.
> Soldering is difficult because the device is so small. You can buy
> one
> mounted on a little circuit board for about $35 from
> http://www.sparkfun.com. Sparkfun also has bluetooth and lots of
> other
> interesting things.
> --
> Ton van den Bogert
> Department of Biomedical Engineering
> Cleveland Clinic Foundation
> http://www.lerner.ccf.org/bme/bogert/
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