From: utzoo!decvax!harpo!floyd!vax135!ariel!deimos!houxi!houxr!ehwest
Newsgroups: net.general
Title: sightless navigation
Article-I.D.: houxr.128
Posted: Fri Oct  8 09:12:57 1982
Received: Tue Oct 12 03:47:02 1982

It seems to me that passive RF or magnetic devices like those used
for inventory control, in libraries, and on some personal identification
badges suffer from an important proximity requirement.  A significant
amount of energy must be coupled into them in order to work at all, which
means they must be either very close to the sensor (inches) or surrounded
by a loop sensor like in stores.  To work well, a person must be able to
identify where he is at a distance of at least 5 feet and probably much
more in wide open areas.
I have thought about the IR -digital transmitter idea a little more and
now I think a transmitter could be built with 2 ics for about $25.  It
would be very much like a remote control TV transmitter but with an 
EPROM to store the message which would be constantly dumped. A 64K EPROM
could store up to 8 full seconds of speech-- enough to fully identify
where you are, which direction you're facing and how to get where youre
going.  Transmitters could be installed in elevators, hallways, outdoors,
or at traffic intersections-- of course at government expense.
Receivers would cost a little more. They would be like pocket pagers. 3 or 4
ics and would cost $50 to $100.
Centralized EPROM recording machines would be required to record the message
into the transmitters memory.
Of course someone would have to pay for all of this, but someone already
pays for handicapped parking spaces, ramps, special elevators, etc.  Why
should blind people have to pay for it themselves?