[sdiy] FUS - Focused Ultrasound, was: Prophet 10 op-amp swaps?

[cheater00 .]

On Wed, Jul 31, 2013 at 10:30 PM,  <rsdio at sounds.wa.com> wrote:
> On Jul 31, 2013, at 12:47, cheater00 . wrote:
>> On Wed, Jul 31, 2013 at 9:20 PM,  <rsdio at sounds.wa.com> wrote:
>>> I recently designed a 32-channel DAC for ultrasonic frequencies
>>
>> really curious, 32-channel ultra-sonic DAC - are you allowed to tell
>> what the application was? I imagine an array of transducers, possibly
>> for measurement purposes, relating to mechanical modes of rigid
>> bodies.
>
> The application is the Soundplane. Your hunch was reasonably correct: the
> Soundplane is a capacitive sensor that detects mechanical deflection of
> capacitive plates within a surface, in order to detect pressure and
> position. This sensor does not rely on human flesh for conductivity, and
> thus the surface can detect drum sticks or any material. In addition, the
> surface is flexible and can also bend. The ultrasonic signals really only go
> up to 60 kHz, with a sample rate of 125 kHz.

I have been wondering if you were aware of this article, which hit the
news just recently?

http://www.extremetech.com/extreme/162678-harvard-creates-brain-to-brain-interface-allows-humans-to-control-other-animals-with-thoughts-alone

Here they use a focused ultrasound method to stimulate a specific
brain centre in the rat. Someone in the comments even gave a fun idea
of using this to stimulate the happiness centre in the human brain.

One method of performing FUS for surgery (at much higher intensities
than needed to merely stimulate) is to use a phased array of
transducers, just like your Soundplane.

http://en.wikipedia.org/wiki/High-intensity_focused_ultrasound#Focusing

It seems like FUS could also be used to stimulate the sense of touch,
so that you can feel you're touching something while in fact you're
touching "thin air".

Cheers,
D.