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[aprssig] Introducing the OpenTracker+

'Scott Miller' scott at opentrac.org
Fri Apr 20 01:29:05 UTC 2007

I'm almost ready to start selling these (except for the SMT version), so I
thought I'd re-post this announcement from the OpenTracker group.  Here's
the short version:  The microcontrollers in the OpenTracker kits are
becoming obsolete.  I'm out of stock and won't have more for several weeks.
Once I do, they'll mostly be held for repairs, replacements, and some
customers who bought bare boards and need to finish kits.  The OT+ kit takes
the place of the OT1x, and is based on a new variant of the same processor,
but has more code space and RAM.  So far, the biggest firmware change is
software-based demodulation capability.  It's not terribly sensitive or
immune to noise (it'll probably get better) but it's still pretty cool, and
adds no cost.  It decodes just about all APRS position packets and outputs
NMEA $GPWPL waypoints.

I may start taking preorders soon.  All of the parts are in, but I don't
have a production schedule for the enclosure silkscreening yet.

Anyway, here's the remainder of the original announcement:


The good news is that the new design is almost ready. I've finished
most of the testing, and the majority of the firmware has already been
tested in the OpenTracker or Tracker2, so I don't expect any major
surprises there. So without further ado, some specs on the new tracker:

* Based on the Freescale MC908JL16CSPE microcontroller. It's the same
HC08 core, but with twice the program space and three times the RAM.

* Different case design. The 32-pin shrink-DIP MCU is taller than the
old 16-pin DIP, so the new case has right-angle D-sub connectors for
more headroom inside. The case is slightly longer overall, but the
jumpers are easier to install now. The layout also allows for
connectors with built-in ferrite filters.

* RX capability. This is the biggest change, but it's still
experimental. In its current state, the demodulator code does at
least a decent job of decoding packets off the air. I expect it to
improve, but I won't make any promises. In a 15-minute drive
yesterday, I received about two pages of waypoints on my GPSmap 60CS.
Waypoint output is in NMEA mode (GPWPL) only, no Garmin binary
support or symbol translation like the Tracker2.

* No trimpots. There's a jumper to set the TX audio level range (high
or low), but all TX and RX adjustment is done in software. This
eliminates a couple of failure-prone parts, as well as the need to
open the case for adjustment.

* Simplified construction. Compared to the OT1x, the OT+ has fewer
parts, and fewer different component values. The resistors are
installed flush with the board rather than vertically, so they're
easier to place and solder.

* Multi-color status LED. Like on the Tracker2, the status LED can be
red, green, or amber. This makes it easier to see what the tracker is

* More analog inputs. Several ADC inputs are available, with 10-bit
resolution. The voltage sensor also has a slightly expanded range.

* Test and diagnostic functions integrated in config program. A new
menu lets you test the outputs (PTT, power, LED) and send test tones.
Temperature sensor calibration will be added soon.

The waypoint output functions occupy a lot of space, but there's still
space left over for new features that wouldn't fit in the OpenTracker.
In particular, I plan to implement some improved telemetry features
in the near future.

Pictures of the new through-hole unit are here:


Also, I've got some surface mount boards built in 24-pin DIP size.
They're completely untested at this point, since I haven't built a
programming adapter yet. They look cool, anyway:


The pictures are also on the Yahoo Group photo section, under Prototypes.

I expect to have the new kits ready to sell in the next two weeks.
The price will be the same as the current OT1x kit.


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