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[aprssig] New APRS virtual reality Idea!

Jim jim at stuckinthemud.org
Thu Sep 20 20:32:23 UTC 2007

This is scary...!

I was talking about exactly the same thing with a friend of mine the other

Expand it to the mobile "room" and quadraphonic (surround sound) becomes a
real possibility. Most cars already have the speakers.

If tied into the direction of travel from a GPS, it could all be relative to
the vehicle.

Alas I don't have any DSP knowledge to know where to start.

Jim, G1HUL

-----Original Message-----
From: aprssig-bounces at lists.tapr.org [mailto:aprssig-bounces at lists.tapr.org]
On Behalf Of Robert Bruninga
Sent: 20 September 2007 19:35
To: 'TAPR APRS Mailing List'
Subject: [aprssig] New APRS virtual reality Idea!

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

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"...


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