[aprssig] (Ab)Use of APRS for telemetry? Anyone doing it?

Scott Miller scott at opentrac.org
Mon Dec 6 11:57:04 EST 2004


>The scheme for sending the telemetry values is very straightford and widely
>implemented, does your hardware support that? If not, you should consider
adding
>it...

Been thinking about it.  It'd probably be a special telemetry firmware
version.  If anyone's got suggestions on how they'd like to see it done, let
me know.  The hardware has 3 analog inputs (0-5 volts, 8 bits) available,
and maybe 2 digital input lines depending on whether you're controlling a
radio power relay or connecting to a 1-wire bus.  The 1-wire bus of course
gives you the ability to connect a lot more sensors, using just the single
input.

The simplest implementation might just output raw 8-bit values as the first
three telemetry readings (0-255).  Dealing with a 1-wire bus gets more
involved, because you need to know the unique ID numbers of each device.  My
weather station firmware avoids that because the V3 Dallas 1-wire station
only has one device of each family, and you can identify them by family
code.

I'm open to any suggestions - just keep in mind that the current OpenTracker
is a receive-only device.  Still, at $29, it's about as cheap a solution as
you're going to find.

Scott
http://n1vg.net/opentracker





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