This scans the surroundings for solid features such as buildings, trees, cars and other people, and produces a tactile map with features 'embossed' onto a flat surface. This could be integrated with a GPS and map system to provide a dynamic map of the roads and pavements immediately surrounding the user.
-- dbmag9, Aug 02 2011

I think this sort of thing has been researched by the VA since the 1970s.
-- AbsintheWithoutLeave, Aug 02 2011


I like the idea of integrating sonar with something interactive like a pin matrix for an ever changing tactile map. (+)
-- 2 fries shy of a happy meal, Aug 02 2011


Definitely Baked, in the form of a "waistcoat" which had a matrix of rods which pressed on the skin of the upper back, corresponding to sonar readings.

Demonstrated on BBC Tomorrow's World in the 1980's.

Widely Known To Exist.
-- 8th of 7, Aug 02 2011


There was also a system that fed the data to a mouthpiece which stimulated various areas of the tongue with electricity.
-- baconbrain, Aug 02 2011


//Gonna be hard to get a full map with sonar coming from a single source//
PPIs were invented by British radar engineers in the 1940s.
Not a "full" map, but from a single point-of-view, about as good as can be expected.
-- AbsintheWithoutLeave, Aug 02 2011


/single-point-of-view/ Sonar at sea is probably all about primary echo: signal goes out, hits sub, bounces back, there is sub. But in a complex environment there would be all sorts of secondary and tertiary echoes which would give you extra information and other "sources".

I have noticed on many occasions that on whistling a note in a stairwell, the resulting echo rises in pitch as it dies. I am not sure if this is a described phenomenon or not. I do not understand how echoing could shorten wavelength of a pure tone, but echoing could select for shorter wavelengths in an impure bunch of tones with the shorter ones less likely to be absorbed, just as the short wavelength blue light is more likely to bounce back out of the sky.

So: could one distinguish a primary echo off a distant object from a simultaneously heard secondary echo off a closer object by the frequency of the echo?
-- bungston, Aug 05 2011


[bungston], there are sonar-using animals that vary the frequency of each chirp as it goes out--"cheeeiiirp", so to speak. The pitch of the echo tells them which part of the chirp is coming back.
-- baconbrain, Aug 05 2011



random, halfbakery