[aprssig] NMEA output GPS or compass?
Greg D
ko6th.greg at gmail.com
Sat Jun 30 01:20:26 EDT 2018
Oops... cancel that. I was thinking of my other GPS (Vista), which
doesn't have a serial port. But there was a model in between the two
that I think does have both a serial port and automatic magnetic compass...
Anyway, just a thought that some of the slightly older equipment might
fit the bill.
Greg KO6TH
Greg D wrote:
> One can pick up a Garmin GPS-III on eBay for about $20. Serial
> interface built-in, but with the round connector. It includes a
> magnetic compass, and switches to it when not moving, at least for the
> internal display - not sure what happens to the serial data strings.
>
> Greg KO6TH
>
>
> John Gorkos wrote:
>> So, does it just want GPHDT? Putting together a microprocessor that
>> reads a 3DOF compass sensor and outputs the NMEA sentence once per
>> second is an Arduino-101 project. Hardest part would be getting the
>> signal levels correct going to the back of the LD-250. The entire thing
>> would fit in an altoids tin (but shouldn't... you know... the whole
>> magnetic field sensor doesn't like that).
>>
>> de AB0OO
>>
>> On 6/29/18 13:41, david vanhorn wrote:
>>> The GPS really would add nothing to the system. Their map is static.
>>>
>>>
>>> On Fri, Jun 29, 2018 at 11:52 AM, John Gorkos <jgorkos at gmail.com
>>> <mailto:jgorkos at gmail.com>> wrote:
>>>
>>> I'm a little late to this, but what input is the LD-250 looking for?
>>> If it's straight NMEA with GPHDT sentences, why not just build your own
>>> little device to do that? Seems to me, you could do the whole thing for
>>> about $80: a $10 Atmega µProcessor like a trinket, a $15 triple-axis
>>> accelerometer board with a LSM303DLHC chip on it, and a $40 GPS board
>>> with NMEA out. Throw in a $10 level converter to get the output signals
>>> up to "true" RS-232 levels, and put a little glue code in there to
>>> generate the GPHDT sentence and mix it with the NMEA stream from the
>>> GPS, and put it all in a nice little box with a power plug on it.
>>>
>>> Heck, send me $80 and give me a week, and I'll send you the box. I've
>>> got everything I need sitting here on my test bench.
>>>
>>> John Gorkos
>>> AB0OO
>>>
>>> On 6/29/18 10:27, david vanhorn wrote:
>>> > Thanks all.
>>> >
>>> > I am going to hold off till I find a fluxgate compass. The GPS route
>>> > would "work" but this thing has enough issues already.
>>> >
>>> > The Boltek LD-250 is " Long Range detection Designed for mobile
>>> use in a
>>> > moving vehicle with a GPS or Compass connected " (From their web site)
>>> > However..
>>> >
>>> > Their software doesn't work with any known map program.
>>> > The unit sends strike information as bearing and distance relative to
>>> > the front side of the sensor.
>>> > If you add a compass, the strikes are rotated accordingly.
>>> > The strikes are not converted to anything like an object at a
>>> coordinate
>>> > though, so if the vehicle is moving, they are "smeared" across the
>>> map.
>>> >
>>> > It's only really useful while moving if the strikes are converted to
>>> > absolute rather than relative coordinates, and then the image is
>>> rotated
>>> > and panned accordingly to the vehicle rotation and motion.
>>> > I could easily live without an actual map
>>> >
>>> > The GPS wouldn't give me workable heading data when not moving,
>>> and the
>>> > LD-250 doesn't give useful data while I am moving..
>>> >
>>> > With a compass, at least I could park in whatever direction works, and
>>> > I'd get a display rotated so that it's oriented north up.
>>> >
>>> > It's a fixed location instrument in a mobile package. The only
>>> plus is
>>> > that it doesn't require a full PC with PCI slot to run.
>>> >
>>> > Basically, in the 10 years since I last used it, the half-assed
>>> > implementation of their software hasn't improved at all. I need
>>> it to
>>> > be at least 3/4 assed. :)
>>> >
>>> > It would be really cool if some working mobile app/program whatever
>>> > could be trained to hear their data and plot it on a working map.
>>> >
>>> > $WIMLI,<ddd>,<uuu>,<bbb.b>*<cs><cr><lf>
>>> >
>>> > <ddd> - corrected strike distance 0-300 miles
>>> > <uuu> - uncorrected strike distance 0-300 miles
>>> > <bbb.b> - bearing to strike 000.0-359.9 degrees
>>> > <cs> - checksum in hex
>>> > <cr> - carriage return
>>> > <lf> - line feed
>>> >
>>> >
>>> >
>>> > http://www.boltek.com/manual-ld-250.pdf
>>> <http://www.boltek.com/manual-ld-250.pdf>
>>> >
>>> > On Thu, Jun 28, 2018 at 7:25 AM, david vanhorn <kc6ete at gmail.com
>>> <mailto:kc6ete at gmail.com>
>>> > <mailto:kc6ete at gmail.com <mailto:kc6ete at gmail.com>>> wrote:
>>> >
>>> >
>>> > I'm reactivating an old project, and I would like to find an NMEA
>>> > output GPS unit like the old Garmins with their four pin connector,
>>> > or a compass with similar output.
>>> >
>>> > What I've seen in compasses are crazy expensive ($500), and GPS
>>> > units seem to all be USB output now if they have any external data
>>> > connection at all.
>>> >
>>> > What I absolutely need at a minimum is a compass or GPS with an NMEA
>>> > output. The system has NMEA+ NMEA-, +12V power to compass/GPS and
>>> > ground. If it's a GPS unit, I would prefer some sort of simple
>>> > "puck" style unit rather than something with a display and buttons
>>> > to misconfigure.
>>> >
>>> > Any sources coming to mind?
>>> >
>>> >
>>> > --
>>> > K1FZY (WA4TPW) SK 9/29/37-4/13/15
>>> >
>>> >
>>> >
>>> >
>>> > --
>>> > K1FZY (WA4TPW) SK 9/29/37-4/13/15
>>> >
>>> >
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>>>
>>> --
>>> K1FZY (WA4TPW) SK 9/29/37-4/13/15
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