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[aprssig] New APRS virtual reality Idea!

Robert Bruninga bruninga at usna.edu
Thu Sep 20 18:35:07 UTC 2007


This is a NEAT idea if anyone wants a fun project.
That also knows how to write some DSP software:

Imagine an APRS product that works like this:

Imagine wearing a pair of headphones. 
Close your eyes and face north.
When an APRS user with a D7 HT speaks,
You HEAR him in the direction where he is.

If he is to the East, you hear him to the right.
If he is to the west, you hear him to your left.
Anywhere in between, and  the earphones are phased so that you
hear his direction.

Now, too bad the APRS PTT mode does not put the position data at
the FRONT of a packet, but at the end.  At the front, you could
know who is talking from where and you could then phase delay
his voice to create the correct virtual postion.   But it isnt.
The packet is at the end.

So, given this end-PTT limitation, then here is how I would
implement this and it also makes it simpler.

1) Pass the voice through both earphones in MONO.
2) When the PTT mode packet comes in
3) Send a "roger-beep" to the earphones.
   (A) Phased to indicate direction 
   (B) Tone frequency to indicate distance.

High tone means close.  Low tone means far.  Any other tone
inbetween...

Once that is working, make it proportional to own-heading, and
now you can "see APRS in the dark"...

Bob, WB4APR





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