[aprssig] Simple APRS module to use with Arduino

[John Gorkos]

You're probably not going to find a built solution for $50.  There's
just no margin in building small runs of APRS devices, and very little
market for large runs.

Your best bet would be a custom board built for task.  If you're going
to build a dozen of them, you can get enough discount on parts to do
them for <$50 each.

I would start here:
http://garydion.com/projects/whereavr/

That's a basic AFSK modem that encodes using a resistor ladder and
decodes using a basic interrupt-driven zero-crossing decoder.  It speaks
KISS, but a smart guy would port this to a Teensy with its vastly
greater processing power, and write a simple interface around it. It
takes NMEA from an external serial port.  You didn't mention anything
about a GPS module.  EBay is full of Ublox Neo 6M modules for under $10.
 The Teensy is $20 from LadyAda.  You'd probably want to spin a custom
"shield" board to mount to the Teensy, where you can mount some screw
terminals or a 3.5mm phono jack, your resistor ladder, your voltage
divider for the receive side, some LEDs, etc.  In quantity 12, you can
get a dozen double sided boards made for <$100, so board cost is under
$9.  The misc parts would probably fill out the remaining $11.  The cool
part is the Teensy has a very nice voltage regulator built in, since it
likes to be fed from a USB port.

Of course, I'm assuming your time is free.  The software is going to
take time.  The basic transmitter and receiver code can be borrowed from
Gary Dion's project, but if you want a KPC-2-style interface, that's
going to take time.  Assembly is going to take time.  Assembly and final
programming would be a great club project, since you could do it all
with through-hole components.

Just some thoughts.
John Gorkos

On 10/14/16 1:54 AM, Jim (List) wrote:
> Thanks, but that’s way out the price range.
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> I’m looking at a built solution (without radio) for about $50.
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> Jim
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> *From:*Robert Bruninga [mailto:bruninga at usna.edu]
> *Sent:* 13 October 2016 22:56
> *To:* Jim (List)
> *Subject:* RE: [aprssig] Simple APRS module to use with Arduino
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> Sure, the Byonics.com Mircotrack  MTT4B and it includes a 10W transmitter.
> 
> bob
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> *From:*aprssig [mailto:aprssig-bounces at tapr.org
> <mailto:aprssig-bounces at tapr.org>] *On Behalf Of *Jim (List)
> *Sent:* Thursday, October 13, 2016 2:49 PM
> *To:* TAPR APRS Mailing List
> *Subject:* [aprssig] Simple APRS module to use with Arduino
> 
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> I’m looking for an APRS add-on module to use with Arduino, providing
> simple TX and RX of APRS beacons.
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> It will primarily be sending messages, but ability to also receive would
> be useful so it can get the message ack.
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> Cost is a factor as, if the project is successful, I’ll be looking to
> build about a dozen units.
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> I’m aware of the Argent Data Shield, wondering if there is anything else
> out there.
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> Jim, G1HUL
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