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Circuit that produces a tingling sensation in the fingers.

R

Rich Grise

Jan 1, 1970
0
But I simply don't see a big market for such product since even my old
machine is no longer made.
/Roland

I hope I'm not being impertinent, but how do you read newsgroups? With
your device we're talking about, or do you have talking software?

Thanks,
Rich
 
R

Rich Grise

Jan 1, 1970
0
The first part of the problem is to find a set of nerves on/in the body
which can be used to "see". The fingertips are sensitive, but very small.

I would try the skin on one of my thighs, it is fairly easy to attach a
thin elastic cloth around it and leave it on all day.

Then I need a way to excite the nerves in the skin of my thigh.

200*300 points, or more, on the inside of the cloth will excite the
nerves and create a picture which wraps around my thigh, and I use the
nerves in the skin to "see" it.

The idea about electrostimulation fits well into this device.
I would simply try different combinations of frequencies and currents
until I found a setting which gave the best "image" without being painful
in any way.
Mechanical stimulation is also possible, but would be a little more
difficult to manufacture.

A small videocamera can be hidden below or above my own face, in a
band around my head, like a tennis player's sweatband, for example.

So I would feel with my thigh what the camera sees.

With some training it could become really useful.

Put the device _in_ the sweatband, and feel it on your forehead.
For my second choice, I'd go chest or back. But as Mr. Woodgate has
mentioned, the thigh is probably one of the least sensitive pieces of skin
that you have. Then again, this might simplify the design.

Y'know, this could turn out to be an interesting project!

But I still say that applying electric shocks doesn't sound like the best
way to do things.

Hey! How about some of those microphonic/piezoelectric SMT caps? ;-)

Good Luck!
Rich
 
R

Roger Johansson

Jan 1, 1970
0
Rich Grise said:
Put the device _in_ the sweatband, and feel it on your forehead.

That is a good idea too, and it would simplify the wiring as the camera
and the skin area are so close. The whole device could be integrated in
the head band. But I wonder if it would be better for feeling where
things are in the picture.
For my second choice, I'd go chest or back. But as Mr. Woodgate has
mentioned, the thigh is probably one of the least sensitive pieces of
skin that you have. Then again, this might simplify the design.

Y'know, this could turn out to be an interesting project!

But I still say that applying electric shocks doesn't sound like the
best way to do things.

I am not talking about painful levels, just a tingling sensation.
Hey! How about some of those microphonic/piezoelectric SMT caps? ;-)

You mean for translation from electrical signals to mechanical?

The beepers in pocket computers are like a piece of tape, thin adhesive
piezoelectric material. It can produce a mechanical movement controlled
by electrical signals. Yes, it could work too.
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Rich Grise <[email protected]>
wrote (in <[email protected]>) about 'Circuit
that produces a tingling sensation in the fingers.', on Fri, 10 Dec
2004:
I hope I'm not being impertinent, but how do you read newsgroups? With
your device we're talking about, or do you have talking software?

The Royal National Institute for the Blind in UK has done an enormous
amount of work on computer aids for blind people. Quite a few years ago,
they has voice-operated writers (needed a lot of training, so not viable
commercially) and readers. The readers would run at speeds far higher
than normal speech and people were trained to understand at those
speeds.
 
S

Spehro Pefhany

Jan 1, 1970
0
I read in sci.electronics.design that Rich Grise <[email protected]>
wrote (in <[email protected]>) about 'Circuit
that produces a tingling sensation in the fingers.', on Fri, 10 Dec
2004:

The Royal National Institute for the Blind in UK has done an enormous
amount of work on computer aids for blind people. Quite a few years ago,
they has voice-operated writers (needed a lot of training, so not viable
commercially) and readers. The readers would run at speeds far higher
than normal speech and people were trained to understand at those
speeds.

The human brain can interpret speech at a much higher speed than
people can speak clearly. There are devices that speed up voice
(essentially by stealing chunks of it, so that it doesn't increase in
pitch) and they are still understandable at much higher than normal
speeds. I wonder if there's a better algorithm that might be practical
today.


Best regards,
Spehro Pefhany
 
Roland said:
Since the late 1970s there were devices available called Optacons.
Unfortunatly this technology has disappeared from the market. It essencially
consists of a neadle array (20 x 5) where such trigger is stimmulated by
vibrating certain sets of these pins at a time.

Roland,

Would you please describe the spacing of the pins as best you can --
or (the overall dimensions of the rectangle? I
have an idea that might reproduce this device's behavior, and be
somewhat scaled up.

Similarly, do you know anything about the
frequency of vibration used? (If memory serves, one peak in human
sensitivity to vibration is around 300 Hz., and I *think* there's
another one (different sensory neurons?) much lower (50 Hz?.)
Unfortunately the neurologist who I recall mentioning the frequency
response is no longer here to ask.

Do you think a quasi-static displacements would work well enough to
use? Fast enough to show sequences of tactile "images" (like a
morph-able wood carving), but not fast enough to feel like a vibration?
In that case, an array of pins displaced by resistance-heated Nitinol
wires might work for a dense, potentially inexpensive device.
Larry Pfeffer
 
Roland said:
Since the late 1970s there were devices available called Optacons.
Unfortunatly this technology has disappeared from the market. It essencially
consists of a neadle array (20 x 5) where such trigger is stimmulated by
vibrating certain sets of these pins at a time.

Roland,

Would you please describe the spacing of the pins as best you can --
or (the overall dimensions of the rectangle? I
have an idea that might reproduce this device's behavior, and be
somewhat scaled up.

Similarly, do you know anything about the
frequency of vibration used? (If memory serves, one peak in human
sensitivity to vibration is around 300 Hz., and I *think* there's
another one (different sensory neurons?) much lower (50 Hz?.)
Unfortunately the neurologist who I recall mentioning the frequency
response is no longer here to ask.

Do you think a quasi-static displacements would work well enough to
use? Fast enough to show sequences of tactile "images" (like a
morph-able wood carving), but not fast enough to feel like a vibration?
In that case, an array of pins displaced by resistance-heated Nitinol
wires might work for a dense, potentially inexpensive device.
Larry Pfeffer
 
G

Guy Macon

Jan 1, 1970
0
John said:
The Royal National Institute for the Blind in UK has done an enormous
amount of work on computer aids for blind people. Quite a few years ago,
they has voice-operated writers (needed a lot of training, so not viable
commercially) and readers. The readers would run at speeds far higher
than normal speech and people were trained to understand at those
speeds.

I have seen ads for devices that speed up speech, either by
removing space between words or by playing it faster without
changing the pitch. I am pretty sure that some local radio
stations do this on some commercials - I don't think that a
human can talk that fast.
 
G

Guy Macon

Jan 1, 1970
0
Spehro said:
The human brain can interpret speech at a much higher speed than
people can speak clearly. There are devices that speed up voice
(essentially by stealing chunks of it, so that it doesn't increase in
pitch) and they are still understandable at much higher than normal
speeds. I wonder if there's a better algorithm that might be practical
today.

An old trick that the books on tape folks do is to speed up the tape
a percentage point or so to avoid having to use a small part of the
last tape. I wonder if I could cobble together a program that gives
me independent control of the length of the silences, vowels, and
consonants...
 
G

Guy Macon

Jan 1, 1970
0
Rich said:
But I still say that applying electric shocks doesn't sound like the best
way to do things.

Hey! How about some of those microphonic/piezoelectric SMT caps? ;-)

Now *that's* an interesting idea!

I think that I could localize a small mechanical buzzer a lot better
that I could localize a shock. I wonder whether a frequency-of-
buzzing to color-of-image maping would be beneficial.

You know, the government likes to give grants to anyone who works
on technology to assist the handicapped...
 
R

Robert Monsen

Jan 1, 1970
0
Guy said:
Spehro Pefhany wrote:




An old trick that the books on tape folks do is to speed up the tape
a percentage point or so to avoid having to use a small part of the
last tape. I wonder if I could cobble together a program that gives
me independent control of the length of the silences, vowels, and
consonants...

Windows already allows you to do this, I believe.

--
Regards,
Robert Monsen

"Your Highness, I have no need of this hypothesis."
- Pierre Laplace (1749-1827), to Napoleon,
on why his works on celestial mechanics make no mention of God.
 
R

Rich Grise

Jan 1, 1970
0
Now *that's* an interesting idea!

I think that I could localize a small mechanical buzzer a lot better
that I could localize a shock. I wonder whether a frequency-of-
buzzing to color-of-image maping would be beneficial.

You know, the government likes to give grants to anyone who works
on technology to assist the handicapped...

At least three times now, I've wasted a day trying to track down that "get
a grant" stuff. I think the bottom line on that is that you have to be
some politician's brother-in-law or something.

If you know how to get a grant, I'd be more than happy to collaborate on
the project itself. I also want to come up with some kind of
neuron-silicon interface for smart prosthetic limbs. And the tactile parts
of both projects would seem to dovetail nicely.

Cheers!
Rich
 
R

Robert Monsen

Jan 1, 1970
0
Rich said:
At least three times now, I've wasted a day trying to track down that "get
a grant" stuff. I think the bottom line on that is that you have to be
some politician's brother-in-law or something.

Matt Lesko (http://www.lesko.com/adlink7/)

--
Regards,
Robert Monsen

"Your Highness, I have no need of this hypothesis."
- Pierre Laplace (1749-1827), to Napoleon,
on why his works on celestial mechanics make no mention of God.
 
H

Hans-Bernhard Broeker

Jan 1, 1970
0
In comp.arch.embedded Rich Grise said:
But I still say that applying electric shocks doesn't sound like the best
way to do things.

Seconded. Keeping in mind that our nerves themselves are operating
based on electricity, I suspect that the basic rule of thumb is:
there's no such thing as safe electrostimulation of sensory nerves.
Your stimulus can either be too weak for anything to be registered at
all, or too strong to be safe.

The margin between these two thresholds on stimulus strength is
probably too small to be safe for everyday usage other than in a
*very* closely controlled environment (say, within shouting distance
of an ICU, with trained medical personnel controlling the apparatus,
given a rather specific medical indication for doing it).
 
R

Roger Johansson

Jan 1, 1970
0
Hans-Bernhard Broeker said:
Your stimulus can either be too weak for anything to be registered at
all, or too strong to be safe.

The margin between these two thresholds on stimulus strength is
probably too small to be safe for everyday usage other than in a
*very* closely controlled environment (say, within shouting distance
of an ICU, with trained medical personnel controlling the apparatus,
given a rather specific medical indication for doing it).

There is a big margin between what can be sensed by the skin and what
could kill you, or damage your body in any way.

But, of course you need to have a brain to do anything with electricity,
just like you need a brain to cross a street without getting killed.

Using normal precaution is of course necessary, like using a small battery
to drive this circuit, not the mains power. And start testing on a suitable
part of the body, like a leg.
 
B

Bob Masta

Jan 1, 1970
0
Seconded. Keeping in mind that our nerves themselves are operating
based on electricity, I suspect that the basic rule of thumb is:
there's no such thing as safe electrostimulation of sensory nerves.
Your stimulus can either be too weak for anything to be registered at
all, or too strong to be safe.

The margin between these two thresholds on stimulus strength is
probably too small to be safe for everyday usage other than in a
*very* closely controlled environment (say, within shouting distance
of an ICU, with trained medical personnel controlling the apparatus,
given a rather specific medical indication for doing it).

I recall from my bioengineering neuroscience class a
discussion of touch-sensing neurons becoming desensitized
from overstimulation. The classic example was the "glass harmonica"
player of (I think) late 1800s. The device was a series of disks of
different diameters and/or thicknesses that rotated on a shaft.
There may have been some mechanism to keep the rims wetted.
The performer played this by lightly touching the rims with his
fingertips, producing sound like you get from running a wet finger
around the rim of a wineglass. The story is that the real virtuoso
perfomers, who played a lot, eventually lost sensation in their
fingertips. This was apparently only due to overstimulation, since
there was no obvious tissue damage at the surface.

On a personal note, I used a "cheater" method of wood carving
many years ago. I would put a rotary file bit in a high-speed
die grinder (like a Dremel on steroids, or a long skinny router)
and carve away. This made carving a breeze, but after a half
hour or so of carving, I found my fingertips had a very strange
sensation. Even with everything turned off, there was still
a tingling. The strangest part was that if I tapped on something,
it felt like my fingers were little tuning forks... they seemed to
"ring" for a few seconds afterward.

Probably just as well I never made a career of this!

Best regards,



Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
 
R

Roger Johansson

Jan 1, 1970
0
This made carving a breeze, but after a half
hour or so of carving, I found my fingertips had a very strange
sensation. Even with everything turned off, there was still
a tingling. The strangest part was that if I tapped on something,
it felt like my fingers were little tuning forks... they seemed to
"ring" for a few seconds afterward.


Strong mechanical vibration have well known negative consequences, like
nerve damage and problems with blood vessels. The circulation is
hampered. But these effects appear at strong vibrations, like when using
a pneumatic sander.

I don't think the device we are talking about would need so strong
vibrations that there is any need to worry about such effects.

We touch and feel things all the time and that does not damage the nerves
or circulation.
 
K

Keith Wootten

Jan 1, 1970
0
Roland Zitzke said:
Since the late 1970s there were devices available called Optacons.
http://www.nfbae.ca/publications/index.php?id=375

Unfortunatly this technology has disappeared from the market. It essencially
consists of a neadle array (20 x 5) where such trigger is stimmulated by
vibrating certain sets of these pins at a time.
This in fact allows detailed pattern recognition without the effect of
distress on the finger.
I am using such device for 25 years now myself and as an engineer I am
constantly looking for techniques to replace / rebuilt it.

<Snip>

I wonder if single line of (say) 16 small needles with 16 photodiodes
(or whatever) controlling them would work? Rather than move your finger
across a fixed array of pins, you have the line of pin/sensors fixed to
your finger and move the line across the object.

Some years ago I tried the electrical stimulation technique but found it
impossible to set a useable frequency/voltage/current. Only small
changes in pressure or moistness varied the stimulus between
undetectable and painful.

Cheers
 
Regarding safety:

Keith said:
Some years ago I tried the electrical stimulation technique but found it
impossible to set a useable frequency/voltage/current. Only small
changes in pressure or moistness varied the stimulus between
undetectable and painful.
I suspect that the basic rule of thumb is:
there's no such thing as safe electrostimulation of sensory nerves.
Your stimulus can either be too weak for anything to be registered at
all, or too strong to be safe.

Neural stimulation can be done safely, though special care is certainly
indicated -- as is keeping well away from the heart, unless you're an
EMT or a cardiologist!

In the U.S. there are devices approved by the FDA, for use (including
home use) for treating chronic pain. Googling
TENS neural stimulation will produce many hits on such. An earlier
poster alluded to 5 mA, and this is in the range mentioned in several
biomedical Eng. texts. That's a rough ballpark, though it doesn't take
into account electrode area, and thus current density. It does,
however, point toward a key aspect of doing this reasonably safety --
controlling the current, very important, given the wide variations in
resistance.

Interested readers may wish to read a related thread on
sci.electronics.design,
thread title "Bipolar current source for muscle stimulations"
(started 23Oct2004.) This thread includes a schematic for delivering a
controlled (bipolar) current, submitted by the estimable Winfield Hill.
-- Larry Pfeffer
(larry underscore pfeffer at verizon dot com)
 
N

Nicholas O. Lindan

Jan 1, 1970
0
I suspect that the basic rule of thumb is:
there's no such thing as safe electrostimulation of sensory nerves.

Bit melodramatic, what?

Big Rule of the Universe #4.3.a:

There is no such thing as no such thing.
 
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