Impact Sensor Ideas.......
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Posts: 46,084
Hi All,
I'm looking to develop a training tool for athletes to wear that could
measure where impacts are sustained (different zones would be fine) and
possibly measure the force of those impacts. My question is: What ideas do
you have for the sensing device(s). Idealy, the sensors would be flexible
and/or soft to comfortable to wear.
All input is appreciated - thanks,
Tim
I'm looking to develop a training tool for athletes to wear that could
measure where impacts are sustained (different zones would be fine) and
possibly measure the force of those impacts. My question is: What ideas do
you have for the sensing device(s). Idealy, the sensors would be flexible
and/or soft to comfortable to wear.
All input is appreciated - thanks,
Tim
Comments
Look into "piezo resistive" materials. These are soft and flexible. I've
played with them a little.
This will get you started:
http://www.piezo.com/index.html
http://www.acx.com/index.html
David
>Hi All,
>
> I'm looking to develop a training tool for athletes to wear that could
>measure where impacts are sustained (different zones would be fine) and
>possibly measure the force of those impacts. My question is: What ideas do
>you have for the sensing device(s). Idealy, the sensors would be flexible
>and/or soft to comfortable to wear.
Check out Beau Schwabe's site - he did a project that used thin flex foil
inductors in conjunction with a metal liner and thin foam to measure force
in foot ware. He measured the change in inductance that occurred as the
pressure changed.
dwayne
Dwayne Reid <dwayner@p...>
Trinity Electronics Systems Ltd Edmonton, AB, CANADA
(780) 489-3199 voice (780) 487-6397 fax
Celebrating 16 years of Engineering Innovation (1984 - 2000)
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This message neither grants consent to receive unsolicited
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>At 01:03 PM 3/12/00 -0800, Tim and Jo wrote:
>>Hi All,
>>
>> I'm looking to develop a training tool for athletes to wear that could
>>measure where impacts are sustained (different zones would be fine) and
>>possibly measure the force of those impacts. My question is: What ideas do
>>you have for the sensing device(s). Idealy, the sensors would be flexible
>>and/or soft to comfortable to wear.
>
>Check out Beau Schwabe's site - he did a project that used thin flex foil
>inductors in conjunction with a metal liner and thin foam to measure force
>in foot ware. He measured the change in inductance that occurred as the
>pressure changed.
>
>dwayne
>
>
Thanks for the "plug" Dwayne...
One thing to watch out for with this design is that only one
"coil" can be polled at a time, otherwise adjacent coils tend to
synchronize in oscillation with each other.
The method used on my webpage works well, allowing a
coil/inductor to resonate in a simple L-C oscillator configuration,
usually in the 3-5MHz range with a 10uH to 40uH coil. Using a 4040B
(12-bit binary counter/divider) the frequency can be divided down to
an appropriate level that a STAMP or PIC can resolve.
The circuit shown requires about 40mA (<--If I remember right).
A new design (patent pending), requires about 100uA and takes approx
15uS to "read" a single coil value.
The "Coils" were specially designed and etched on a 2 layer
flexible circuit board in a "pancake" form, spiraling outward
occupying an area about the size of a nickel.
BTW) To Everyone!
I don't know how much longer my site will be active... I am planning
on moving to Tucker, GA near the first of April and will be changing
my internet provider. I will will inform the list when the change
has been made.
Tim
Original Message
From: Beau Schwabe <bschwabe@i...>
To: basicstamps@egroups.com <basicstamps@egroups.com>
Date: Monday, March 13, 2000 7:26 PM
Subject: [noparse][[/noparse]basicstamps] Re: Impact Sensor Ideas.......
>At 12:19 PM 3/13/00 -0700, you wrote:
>>At 01:03 PM 3/12/00 -0800, Tim and Jo wrote:
>>>Hi All,
>>>
>>> I'm looking to develop a training tool for athletes to wear that
could
>>>measure where impacts are sustained (different zones would be fine) and
>>>possibly measure the force of those impacts. My question is: What ideas
do
>>>you have for the sensing device(s). Idealy, the sensors would be
flexible
>>>and/or soft to comfortable to wear.
>>
>>Check out Beau Schwabe's site - he did a project that used thin flex foil
>>inductors in conjunction with a metal liner and thin foam to measure force
>>in foot ware. He measured the change in inductance that occurred as the
>>pressure changed.
>>
>>dwayne
>>
>>
>Thanks for the "plug" Dwayne...
> One thing to watch out for with this design is that only one
>"coil" can be polled at a time, otherwise adjacent coils tend to
>synchronize in oscillation with each other.
> The method used on my webpage works well, allowing a
>coil/inductor to resonate in a simple L-C oscillator configuration,
>usually in the 3-5MHz range with a 10uH to 40uH coil. Using a 4040B
>(12-bit binary counter/divider) the frequency can be divided down to
>an appropriate level that a STAMP or PIC can resolve.
> The circuit shown requires about 40mA (<--If I remember right).
>A new design (patent pending), requires about 100uA and takes approx
>15uS to "read" a single coil value.
> The "Coils" were specially designed and etched on a 2 layer
>flexible circuit board in a "pancake" form, spiraling outward
>occupying an area about the size of a nickel.
>
>
>BTW) To Everyone!
>
>I don't know how much longer my site will be active... I am planning
>on moving to Tucker, GA near the first of April and will be changing
>my internet provider. I will will inform the list when the change
>has been made.
>
>
>
>eGroups.com Home: http://www.egroups.com/group/basicstamps/
>http://www.egroups.com - Simplifying group communications
>
>
http://www.ionet.net/~bschwabe/
http://www.ionet.net/~bschwabe/BasicStampII/0000.html
http://www.ionet.net/~bschwabe/BasicStampII/Coilread.gif
> Thanks for the help guys! Beau, at what address can I find your site?
>
>Tim
>
>>>>Hi All,
>>>>
>>>> I'm looking to develop a training tool for athletes to wear that
>could
>>>>measure where impacts are sustained (different zones would be fine) and
>>>>possibly measure the force of those impacts. My question is: What ideas
>do
>>>>you have for the sensing device(s). Idealy, the sensors would be
>flexible
>>>>and/or soft to comfortable to wear.
>>>
>>>Check out Beau Schwabe's site - he did a project that used thin flex foil
>>>inductors in conjunction with a metal liner and thin foam to measure force
>>>in foot ware. He measured the change in inductance that occurred as the
>>>pressure changed.
>>>
>>>dwayne
>>>
>>>
>>Thanks for the "plug" Dwayne...
>> One thing to watch out for with this design is that only one
>>"coil" can be polled at a time, otherwise adjacent coils tend to
>>synchronize in oscillation with each other.
>> The method used on my webpage works well, allowing a
>>coil/inductor to resonate in a simple L-C oscillator configuration,
>>usually in the 3-5MHz range with a 10uH to 40uH coil. Using a 4040B
>>(12-bit binary counter/divider) the frequency can be divided down to
>>an appropriate level that a STAMP or PIC can resolve.
>> The circuit shown requires about 40mA (<--If I remember right).
>>A new design (patent pending), requires about 100uA and takes approx
>>15uS to "read" a single coil value.
>> The "Coils" were specially designed and etched on a 2 layer
>>flexible circuit board in a "pancake" form, spiraling outward
>>occupying an area about the size of a nickel.
>>
>>
>>BTW) To Everyone!
>>
>>I don't know how much longer my site will be active... I am planning
>>on moving to Tucker, GA near the first of April and will be changing
>>my internet provider. I will will inform the list when the change
>>has been made.
>>
>>
>measure where impacts are sustained (different zones would be fine) and
>possibly measure the force of those impacts. My question is: What ideas do
>you have for the sensing device(s). Idealy, the sensors would be flexible
>and/or soft to comfortable to wear.
>
>All input is appreciated - thanks,
So long as you aren't looking for super-accurate, highly repeatable readings
(I assume you're just looking for registration of impact, and a general
sense of how hard it was), you can roll your own sensors cheaply and easily.
Take a sheet of conductive, static-proofing foam (The kind they ship/store
CMOS ICs in), and sandwich it between two conductive plates, sheets, wires,
etc. The resistance responds inversely to the amount of pressure being
applied (low resistance == high pressure). The stiffness of the foam
determines the pressure range and restitution of your sensor.
This works well for things such as grip sensors in robotics, where you can
specify approximate grip strengths to be applied. Accuracy and
repeatability leave a bit to be desired, but whaddaya want for something you
can make for free?
Sorry I took so long to throw in my $0.02...
-- Pat
______________________________________________________
could
>measure where impacts are sustained (different zones would be fine) and
>possibly measure the force of those impacts. My question is: What ideas
do
>you have for the sensing device(s). Idealy, the sensors would be flexible
>and/or soft to comfortable to wear.
>
>All input is appreciated - thanks,
Back a few years ago at the WESCON trade show, a company called Tekscan
(800-248-3669, Boston) was showing off a product called F-SCAN, billed as
"the most advanced in-shoe foot force and gait analysis system". The
sensor was a double sheet of polyester, with a pattern of resistive ink and
conductive paths, in a shape to fit inside a shoe. A ribbon of polyester
came up the ankle and to about 100 plated contacts, thence to a harness,
thence to a computer to display pressure as function of location on the
bottom of the foot. I don't know if they are still in business. Contact
me off-list with your fax number if you would like me to fax you the PR
sheet. They were even giving out samples of the in-shoe contact device,
and also one for dentistry. I kept them, so cool they were.
There are other companies that make thin pressure sensors out of conductive
inks. IMRC (520-749-1920 Tucson) made one called the "Prescon". Force
Imaging (800-348-3240 Chicago) made the "Uniforce". Interlink
(805-684-2100 Santa Barbara) made an "FSR (force sensing resistor)". All
dated leads.
-- Tracy Allen
Electronically Monitored Ecosystems
http://www.emesystems.com
>> I'm looking to develop a training tool for athletes to wear that
>could
>>measure where impacts are sustained (different zones would be fine) and
>>possibly measure the force of those impacts. My question is: What ideas
>do
>>you have for the sensing device(s). Idealy, the sensors would be flexible
>>and/or soft to comfortable to wear.
>>
>>All input is appreciated - thanks,
>
>Back a few years ago at the WESCON trade show, a company called Tekscan
>(800-248-3669, Boston) was showing off a product called F-SCAN, billed as
>"the most advanced in-shoe foot force and gait analysis system". The
>sensor was a double sheet of polyester, with a pattern of resistive ink and
>conductive paths, in a shape to fit inside a shoe. A ribbon of polyester
>came up the ankle and to about 100 plated contacts, thence to a harness,
>thence to a computer to display pressure as function of location on the
>bottom of the foot. I don't know if they are still in business. Contact
>me off-list with your fax number if you would like me to fax you the PR
>sheet. They were even giving out samples of the in-shoe contact device,
>and also one for dentistry. I kept them, so cool they were.
>
>There are other companies that make thin pressure sensors out of conductive
>inks. IMRC (520-749-1920 Tucson) made one called the "Prescon". Force
>Imaging (800-348-3240 Chicago) made the "Uniforce". Interlink
>(805-684-2100 Santa Barbara) made an "FSR (force sensing resistor)". All
>dated leads.
>
> -- Tracy Allen
> Electronically Monitored Ecosystems
> http://www.emesystems.com
>
Tracy,
These sensors are "Smile" ...One reason we developed our own sensor
for the purpose of monitoring pressures inside a prosthetic foot or
a diabetic foot with the onset of "distal neuropathy" (<-loss of
feeling in the extremities).
The FSR's from TEKSCAN will not last long under the SHEER stresses
inside a shoe, and quickly become "de-laminated". Any deep creases
and the sensors become saturated. The software allows you to
"normalize" or "zero-out" the returned values to accommodate for
any sensor bending, but again, when you do this it severely dulls
the response and range of the sensor.
The TEKSCAN sensor is great if you are standing still, but for any
"real" gait analysis where a patient must walk, the sensors poorly
survived our study. After $10K+ we quickly learned our lesson the
hard way.
>>Back a few years ago at the WESCON trade show, a company called Tekscan
>>(800-248-3669, Boston) was showing off a product called F-SCAN, billed as
>>"the most advanced in-shoe foot force and gait analysis system". The ...
Beau wrote:
> These sensors are "Smile" ...One reason we developed our own sensor
> for the purpose of monitoring pressures inside a prosthetic foot
or
> a diabetic foot with the onset of "distal neuropathy" (<-loss of
> feeling in the extremities).
>
> The FSR's from TEKSCAN will not last long under the SHEER stresses
> inside a shoe, and quickly become "de-laminated". Any deep
creases
> and the sensors become saturated. The software allows you to
> "normalize" or "zero-out" the returned values to accommodate for
> any sensor bending, but again, when you do this it severely dulls
> the response and range of the sensor.
>
> The TEKSCAN sensor is great if you are standing still, but for any
> "real" gait analysis where a patient must walk, the sensors poorly
> survived our study. After $10K+ we quickly learned our lesson the
> hard way.
Interesting. That goes to shoe again the difference between concept and
reality. I can appreciate how these laminates would have a problem with
shear stress. Tekscan had a patent on the sensor arrays (#4734034)--maybe
they will find a stickier, more elastic ink, or a more suitable
application?
-- Tracy
be a starting point.
At 01:03 PM 3/12/00 -0800, you wrote:
>Hi All,
>
> I'm looking to develop a training tool for athletes to wear that could
>measure where impacts are sustained (different zones would be fine) and
>possibly measure the force of those impacts. My question is: What ideas do
>you have for the sensing device(s). Idealy, the sensors would be flexible
>and/or soft to comfortable to wear.
>
>All input is appreciated - thanks,
>
>Tim
>
>
>
>-- Check out your group's private Chat room
>-- http://www.egroups.com/ChatPage?listName=basicstamps&m=1
>
>
>
Larry G. Nelson Sr.
mailto:L.Nelson@i...
http://www.ultranet.com/~nr