
Friction simulation on touchscreen - cr4zy
http://cnettv.cnet.com/senseg-demos-prototype-touch-feedback-technology/9742-1_53-50115714.html?tag=cnetRiver
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po
Oddly enough, I think I know exactly what this feels like because I have felt
something like this on a laptop that was plugged into an ungrounded outlet.
The metal surface felt like it had ridges as I dragged my finger across the
surface... 60hz ridges. When my finger wasn't moving if felt no different.
When I unplugged it, the sensation went away.

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noonespecial
I've noticed that a few times myself. Most noteably badly grounded proaudio
gear made the mics feel "rough" when plugged in. Its a well known warning sign
that something's amiss and could become dangerous.(1)

I went so far as to make a little medium voltage amplifier and hook it up to
my signal generator so I could try various frequencies and powers. Lots of
strange and wonderful textures emerged but it always felt a bit _tingly_ ,
like I was getting a mild shock. Hopefully they've figured out how to keep
this from happening while still keeping the good part.

(1) Every once in a great while someone is hurt or killed touching a
microphone connected to a malfunctioning mixer/amplifier.

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cpr
If this really works with reasonably low power, you can bet the big guys are
lining up for a bidding war. This is the kind of feature which an Apple or a
Samsung would want to have exclusively, at least for a while.

E.g., Apple seems to have bought all the consumer electronics output of the
metal-moldable-like-plastic company (forget the name) a while back, though we
haven't seen the results publicly yet.

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Roritharr
They are carefully not mentioning battery consumption... i'd expect it to be
high for a system that remodulates the electrical charge on its surface
periodically.

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danmaz74
This would be not just cool, but really useful in terms of usability. I'm
surprised there are so few upvotes...

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shimfish
Any idea if this works with more than one finger at a time?

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bigfoot
For stationary setups, this is for the first time a real win for touchscreens
in comparison to a conventional screen plus a pointing device (mouse,
trackball, you name it). I'm really curious what they'll make out of this.

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Cyndre
I would love to have a touchscreen keyboard with this functionality in it.
This is the biggest thing missing from touch screens presently. Very excited
to see what comes from it.

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maeon3
It uses Coulomb's law, a principle of attraction between electrical charges:

<http://senseg.com/technology/senseg-technology>

Physics behind it:

<http://en.wikipedia.org/wiki/Coulomb%27s_law>

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tocomment
I still don't understand. How does running a current through an electrode
produce an attractive force to a finger? The finger isn't going to have
positively charged particles in it.

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icegreentea
A net neutral finger is still composed of negative and positive particles.
Remember that the negatively charged particle (electrons) are relatively
mobile. If you apply an external electrostatic gradient across a region, you
end up with those electrons moving.

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tocomment
So is this a repulsive or attractive force? Can you control that?

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a-priori
Attractive only.

If I remember my electrostatics, the rationale is that if the surface becomes
positively charged, the positive charges in your finger will move away from
the surface, leaving only the negative charges near the surface. Those
particles will be attracted to the screen. If you reverse the charge so the
surface is negatively charged, then the negative charges in your finger will
be repulsed, leaving positive charges which will be attracted to the screen.
Either way, your finger gets attracted to the screen.

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icegreentea
For more detail (and to correct my previous post a bit), in materials with low
electron mobility (aka insulators), what happens isn't so much the movement of
charge carriers, but rather the orientation of each atom's electron field.
Basically, by imposing a strong gradient, it will cause each individual atom's
electron cloud to reorient/shift, which causes each atom to set up it's own
little gradient which points in the opposite direction.

You sum up those little reorientations amongst all particles in the material,
and you end up with a net electric field that points in the opposite
direction, which then becomes attractive.

The above is a bit more accurate description of what happens in insulators
(which accurately models some parts of our skin), while a-priori's description
fits the conductor parts (most of the wet bits) of the human finger better.
And obviously, this is just an approximation/model of what's going on.

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tocomment
So is this an effect I can create on my Arduino? How do I go about setting it
up?

