Circuit that produces a tingling sensation in the fingers.

Hello all

Without going into the application in too much detail we are looking into the possibility of allowing the identification of items through a persons sense of touch.

So what I am researching at the moment is passing a waveform down a pair of wires which when held (the wires that is) will allow the person to identify that they have the correct item (correct pair of wires in this case).

Is there any information out there on this sort of thing? Has anybody tried this before? What sort of safety regulations etc. apply?

Any help or suggestions appreciated.

Regards

Denis

Reply to
Denis Gleeson
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Limit to 5ma (c.f. GFI)

Maybe you wanto have a finger worn device that delivers the "tingle code" based on RFID? That could enable a blind clerk to work at a store someday.

I suggest you look into PWM (pulse width modulation).

Prior electrocutaneous example:

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Reply to
Rick Merrill

I don't know what regulations apply but it seems like this would be exceptionally dangerous for people with electronic life-suppor equipment implanted in their bodies. (I'm thinking of pacemakers here.)

Just something to keep in mind. Sorry I don't have any real information.

--Mac

Reply to
Mac

To expand on what others have said, the main safety issue is going to be keeping the current from passing through the heart (for pacemakers of just those with sensitive hearts), which basically means somehow guaranteeing that the current path is all in one hand, never from one hand to the other, or to an external ground, etc.

One practical problem you will quickly encounter is that the voltage needed to produce a given current varies quite widely, since the skin pads of the finger tips are not very conductive when dry.

Best regards,

Bob Masta dqatechATdaqartaDOTcom D A Q A R T A Data AcQuisition And Real-Time Analysis

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Reply to
Bob Masta

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Reply to
dmm

An easier solution would be to use vibration, a small vibration motor (the type used in pagers), for instance, attached to the item can give the same tactile feeling (tingling) without the danger or headaches of passing currents thru items (and people!). Whether its practical or not depends on your specific application.

Reply to
steve

Very silly and exceedingly dangerous idea. No lawyer or insurance company will touch you with a fifty-foot cattle prod.

Modulate the speed of a pager motor held in the hand. You can find good examples of this kind of technology in the sex toy industry (and I am not being facetious). See for instance . If the intended users of this appliance can tell the difference between the various settings, then your intended users will be able to, also.

Reply to
Lewin A.R.W. Edwards

This may not be very practical. The sensitivity level (too little/too much) is in a rather narrow range and varies greatly between persons. What one may not feel another goes OUCH. As ohters have stated, use some kind of vibrating transducer, piezo or micromotor.

- YD.

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Reply to
YD

Check out the medical device called a "Tens" unit, it's send a small tingle.

Reply to
Jim Douglas

"Denis Gleeson" schrieb im Newsbeitrag news: snipped-for-privacy@posting.google.com...

Since the late 1970s there were devices available called Optacons.

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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.

Applying electricity directly to the finger is imho not a good idea. Apart from safety considerations and possible long-term electrolytic effects I would assume that you'll lose sensitivity for this after a while. Vibrating mechanics of some kind triggered by something like an AC current would work but in order to provide useful information this requires a complex mechanical setup - just like on the Optacon.

The most promissing approach that I ever considered is to create haptical stimulation by electrostatic / magnetic fields similar to what you can experience if you switch your old model color TV off and touch the tube glass. If one would switch such fields on and off quickly, shield the whole thing by some polymer with a suitable electronegativity characteristic and then put the finger right on this plastic it may be possible to trigger a certain part of the finger for a short time and - as a result - produce a picture. This is what the optacon does but the approach could result in a much less gragil technology with higher resolution and lower costs.

/Roland

Reply to
Roland Zitzke

I read in sci.electronics.design that Roland Zitzke wrote (in ) about 'Circuit that produces a tingling sensation in the fingers.', on Wed, 8 Dec 2004:

That would be a very distinct advantage. (;-)

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Reply to
John Woodgate

Roland, is this a device to help you see? I've read about these, but never actually had any direct contact. Can you recognize different faces? Or the fact that a face is in front of you?

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Reply to
Robert Monsen

After I have read this post, I have had the idea, that I would be able to propose a novel idea for this purpose, that may be very attractive, because this allows to makes devices with even large surfaces, that can produce even large pictures. This idea is based on may experience, and this is the reason, whyI think, that this will work, but it requires some money for the development. The device will not contain any moving elements.

If somebody is interested in it, I would be able to do this development and create a product. This can be surely patented.

Wieslaw Bicz

---------------========== OPTEL sp. z o.o. ===========---------------

------===== R&D: Ultrasonic Technology/Fingerprint Recognition ====------ ul. Otwarta 10a PL 50-212 Wroclaw Tel.:+48 71 3296854 Fax.:+48 71 3296852

--------==== mailto: snipped-for-privacy@optel.pl -=-

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Reply to
Wieslaw Bicz

Yes, I use it because I am blind and it lets me recognize images when moving a CCD camera over it.

As mentioned the represented image is quite small (20 x 5) and this is not enough for recognizing complex structures like a face in the sence that I could tell two faces apart. Biometry is a science of it's own ;-)

With a device I suggested it could be a much larger image and that would certainly enable "TV for the blind" to some degree.

/Roland

Reply to
Roland Zitzke

"Wieslaw Bicz" schrieb im Newsbeitrag news: snipped-for-privacy@optel.pl...

Yes, I guess it would be possible to apply a core technology similar to displaying TV pictures line by line.

experience, and

You are right, and this is probably the problem why such technology is not further developed or even sold.

The device will not contain any moving

Sure not, the three things I see as obstacles is a) To find a suitable surface material b) to find components which are able to switch a high voltage on and off with high frequency and deflect it. c) Do extensive testing to see if the approach as such works as we think it might word.

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

Reply to
Roland Zitzke

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.

--
Roger J.
Reply to
Roger Johansson

I read in sci.electronics.design that Roger Johansson wrote (in ) about 'Circuit that produces a tingling sensation in the fingers.', on Fri, 10 Dec 2004:

IIRC, you have picked the body area where nerves in the skin are most sparse.

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Reply to
John Woodgate

That may be so but the number of receptors is big enough. Touch the thigh anywhere very lightly and you will feel it and you can tell exactly where it is touching.

I thought about the back of the body first, because it is big area, but it would need some kind of adhesive and very flexible surface to stay in contact with every piece of skin. An elastic cloth around the thigh stays in contact with every piece of skin under it.

To make a prototype I would try to find a very thin and flexible wire, which I could fix in the cloth, by sewing into the fabric. At the end of the wire I would take off the isolation for a few millimeters and make a loop or knot which does not irritate the skin mechanically. (copper wire may irritate the skin, so I would get some other surface metal on the wire, or chemically add a layer of zink or whatever works better against the skin than copper)

Then I need a microprocessor which can be programmed to take the average of the light level in one small area of the video picture and send a signal of that level to the skin. Maybe 4*4 pixels for each skin stimulation point. (Because the number of pixels in the camera will probably be much higher than the number of pixels in my thigh cloth.)

We need controls for intensity and contrast for the skin. They will work just like the intensity and contrast control on a tv. I might want to adjust these controls during the day, and when I sleep I turn down to black screen, or take of the cloth.

--
Roger J.
Reply to
Roger Johansson

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.

I am not talking about painful levels, just a tingling sensation.

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.

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Roger J.
Reply to
Roger Johansson

I read in sci.electronics.design that Rich Grise wrote (in ) 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.

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Regards, John Woodgate, OOO - Own Opinions Only. 
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Reply to
John Woodgate

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