Circuit that produces a tingling sensation in the fingers.

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

In message , Roland Zitzke writes

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

it

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)

Good deal! Your $500 bill is in the mail.

-- Keith

Hmm. thats a deal! is 100 all you have in stock! :)

Bit melodramatic, what?

Big Rule of the Universe #4.3.a:

There is no such thing as no such thing.

I read in sci.electronics.design that Nicholas O. Lindan wrote (in ) about 'Circuit that produces a tingling sensation in the fingers.', on Tue, 14 Dec 2004:

Quite right. Now I have a special bargain for you. A hundred $6 bills for $500.

I read in sci.electronics.design that Keith Williams wrote (in ) about 'Circuit that produces a tingling sensation in the fingers.', on Tue, 14 Dec 2004:

Sorry, I can only accept four $125 bills, or three £133.33 bills.

Absolutely not. (;-)

John Woodgate wrote: >

Discount eh?

You have to realize that John Woodgate is so old that when he learned the multiplication table it was still very new, and still contained some faulty results. The multiplication tables have been debugged since then.

It took me a while to get used to their FSF[*] system.

Ten ounces to the pound?

I really didn't want to explain, but I suppose I must. The $133.33 bills are much rarer, and sell to collectors at over $2500 each.

I'd even accept a genuine 1952 English penny.

Roger Johansson wrote: > You have to realize that John Woodgate is so old that when he learned the

John, like myself, was taught the tables in an age when you had to be prepared to change base several times within a single problem. 12d = 1s,

Paul Burke

His lame defence surprised me, I thought he would say something like this:

"Well, I was the chairman of the committee which set up the multiplication tables, and the other guys on that committee messed it up."

Then he would try to blame his old friends, Euclid, Pythagoras, Archimedes, and those arabs with names you cannot pronounce, like Al-Khowarismi (AKA mr. Algoritm) who wrote the book Kitab al-jabr wa al-muqabalah, (al-jabr was later pronounced as "algebra").

We also had to convert from £133/6/8 to £133.33 *mentally* and £24.737 to £24/14/8 and three farthings as well. Mental calculation in base 960.

I read in sci.electronics.design that Roger Johansson wrote (in ) about 'Circuit that produces a tingling sensation in the fingers.', on Wed, 15 Dec 2004:

I never blame other people, even though it's always their fault. And I meant it about the penny, but not the £15 copies you can buy on the web. A real one would produce a tingling sensation in anybody's fingers. (;-)

I read in sci.electronics.design that John Fields wrote (in ) about 'Circuit that produces a tingling sensation in the fingers.', on Wed, 15 Dec 2004:

Not in the same ball-park.(;-) There are five known nickels, but there is only ONE known 1952 English penny.