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Joel A. Vilensky
09-19-1996, 06:46 AM
Colleagues:

Thanks to all who responded to my inquiry on this subject. The informative
responses are reprinted below:
From: MX%"iallison@info.curtin.edu.au" 18-SEP-1996 20:46:18.48
To: MX%"vilensk@CVAX.IPFW.INDIANA.EDU"
CC:
Subj: Re: paw-switches

Joel I would suggest placing an accelerometer on the shank, (as a pilot use
some video display to correlate/validate the characteristics (with some
calculus)). The technology is simpler and it would probably be much better
tolerated by the K9
Worth a try..
Cheers
Garry.

Garry T Allison PhD. Lecturer,
School of Physiotherapy, email:iallison@info.curtin.edu.au
Curtin University of Technology, Tel. +61 9 351 3648
Selby Street, Shenton Park, Fax. +61 9 351 3636
Western Australia 6008
http://www.curtin.edu.au/curtin/dept/physio/pt/staff/allison/
Spinal Cord Injury Research add on "sci/sci_front_page.html" to above www

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From: MX%"janusbla@nencki.gov.pl" 19-SEP-1996 07:33:10.89
To: MX%"vilensk%CVAX.IPFW.INDIANA.EDU@plearn.edu.pl"
CC:
Subj: Re: paw-switches

Dear Joel
Best regards from Poland. How are you doing?
I spent several years to developed contact switches for dog. It is not a
trivial problem. First question is: Do you have a conductive rubber belt
in you treadmill. It woul make you life easier. So please let me know
what setup you have. Maybe you should visit me in Poland and it would
solve your problem

Janusz

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From: MX%"alauer@chsd.org" 18-SEP-1996 12:49:18.89
To: MX%"vilensk@CVAX.IPFW.INDIANA.EDU"
CC:
Subj: Re: paw-switches


Joel,

Perhaps you might want to try looking at BTS from Italy or Vicon out of
Los Angeles. At the Motion Analysis Laboratory in San Diego, we make
ours in house using a metal plate embedded in foam and covered with a
heavy tape.

AnnaLisa Lauer, MA

__________________________________________________ __________

From: MX%"tashman@bjc.hfh.edu" 18-SEP-1996 11:49:59.78
To: MX%"vilensk@CVAX.IPFW.INDIANA.EDU"
CC:
Subj: Re: paw-switches



Joel,

We were faced with a similar problem trying to synchronize data
collection to paw strike during canine treadmill gait. We were afraid
that placing a switch or shoe on the paw might alter the dog's gait,
so we looked for alternatives.

We found that we could get a very consistent indication of paw contact
with an accelerometer taped over the tibial plateau, oriented to
detect acceleration along the long axis of the tibia. There is a very
clear high-frequency spike which occurs at the time of paw strike,
which has been consistent with every dog we have tested (9 so far).
The spike is usually large enough so that we can create a trigger
pulse from the raw analog accelerometer signal and a simple threshold
comparator, but running the signal through an analog high-pass filter
first improves reliability. If you are going through an A/D
converter, a fast sample rate is required to avoid missing the spike
(we use 2000Hz).

Please contact me directly if you want more details.

Scott

************************************************** ****
Scott Tashman, Ph.D.


Head, Motion Analysis Section Assistant Professor
Bone and Joint Center Department of Orthopaedics
Henry Ford Hospital School of Medicine
2799 W. Grand Blvd. Case Western Reserve University
Detroit, MI 48202


Voice: (313) 876-8680 or 876-7572
FAX: (313) 556-8812 or 876-8064
Internet: tashman@bjc.hfh.edu
************************************************** ********
__________________________________________________ _________
From: MX%"foo@walt.ccs.fau.edu" 18-SEP-1996 10:27:25.41
To: MX%"vilensk@CVAX.IPFW.INDIANA.EDU"
CC:
Subj: RE: paw-switches


ONE SUGGESTION:

LOOK AT THE "SHOES" OF SLED DOGS THAT ARE USED TO PROTECT THEIR FEET
ON THE ICE
FOR SUGGESTIONS AS TO FIT, ETC. I BELIEVE SEVERAL IDITAROD RACERS ARE
ON THE
WEB PAGE. GOOD LUCK
PAT

__________________________________________________ ___________

From: MX%"Kevin_Flick@TERC.EDU" 18-SEP-1996 09:00:14.90
To: MX%"vilensk@CVAX.IPFW.INDIANA.EDU"
CC:
Subj: Re: paw-switches



Reply to: RE>paw-switches

Hello Joel,

I am a novice in these matters, but it seems to me that the idea of a shoe is
unecessary. There are flexible membrane switches that are small enough to
glue them right on the pad. The minimalist approach, from the dog's
perspective, is to cover your treadmill in a metal lame' and affix a very
small wire to the dog's foot, so that a circuit is made each time the wire
touches the lame'.

Have Fun,
Kevin Flick

--------------------------------------
Date: 9/18/96 9:38 AM
To: Kevin Flick
From: vilensk@CVAX.IPFW.INDIANA.EDU

__________________________________________________ ___________





From: MX%"mjack@tricity.wsu.edu" 18-SEP-1996 10:31:36.67
To: MX%"vilensk@CVAX.IPFW.INDIANA.EDU"
CC:
Subj: Re: paw-switches



I devised a switch for my dissertation that is similar to your needs. The
only difference is that it was placed on a bicycle instead of a dog.

I used a reed switch. It was mounted on the downtube of the bicycle
frame. The actuator was a magnet and mounted on one crank. Thus every
time the crank passed the reed switch, a signal was imparted to the
minicomputer. This measured the frequency of the cyclist during data
collection.

In order to mount the reed switch to the frame, I used pvc flat rods that
were shaped appropriately and secured like a goniometer. For dogs, a
similar configuration could be used. The distance between the reed switch
and the magnet was very small (3 mm) for my purpose and may pose a
challenge for your use. The greater the distance, the weaker the magnetic
field strength.

This is all explained in my dissertation: "Distribution of
Cycling-Induced Saddle Stresses" Martha Jack, Washington State
University, 1981. It is available thru University Microfilm and
interlibrary loan from the U. of Michigan.

If you wish to post this information the rest of the ISB group with other
responses to your query, you are welcome to.
__________________________________________________ ____________________
Martha Jack, Ph.D. :) E-mail: mjack@beta.tricity.wsu.edu
Biomechanical Engineer :) Voice: (509) 943-0043
___o P.O. Box 776 :) FAX: (509) 943-4642 ___o
_ \