When most people think of Sonar they think of submarine
pings are bats finding mozzies. The problem is that the power needed to tune in
on echoes is pretty advanced stuff and beyond the capabilities of most smart
devices...
But sound presents some wonderful location possibilities
compared to radio waves.
One problem with radio waves is that they travel at the
speed of light and this means that if you use the signals themselves for
measuring distance, you have to have a timing system that is accurate to parts
of a nanosecond to measure small distances..
Here is my proof:
speed = distance/ time
speed of light ie 186,000 m/per hr= 186,000miles/ 1hr
To measure 10 metres at the speed of light is a flash of
time.
According to my research most smart phones can accurately
measure time down to as little as 14 nanoseconds i.e. 14 billionths of a
second.
So at 299,792,458 m/s (speed of light) the accuracy in
meters of a smart device able to measure time at 14 nanoseconds or more is
14* 0.0000000001 of a second times 299,792,458 meters which
equals 4.19 meters!!!
This is a big ask and fraught with accuracy problems but
this is the theoretical accuracy and is not far off what most of us experience
with our own GPS location experiences when everything is working properly...
Now let’s try Sound instead of light in the same equation
However consider what happens when you use Sound instead of
Light... the accuracy.
Speed of sound is 340.29 meters per second
The accuracy of a smart phone is 14 billionths of a second i.e.
14 nanoseconds
Therefore the accuracy of a sound based location system
should be
14* 0.0000000001*340.29
= 4.76406 × 10^-6 !
So lets say it should be accurate to the millimetre!
That’s pretty accurate.
The problem is that sound has limited range... but that’s ok
since stuff you want to measure really accurately is usually only in close
proximity.
Sizes of rooms, location of stuff in rooms, at meeting
halls, in offices, in garages and workshops...
Now the job is how to make all
this practical.