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CRocket
05-27-2010, 01:04 AM
Has anyone had any luck using the PMB-248 GPS receiver module with the Propeller or specificly the Prop Demo Board?

hover1
05-27-2010, 01:33 AM
Try this link:

·http://forums.parallax.com/showthread.php?p=895777

It's a slightly different module, it's run in the "RAW" mode which is the same as your module, (just outputs NMEA strings).

Use a 10K resistor inline from the GPS TTL output (TX) to the Propeller input pin, (you don't need to connect the GPS RX pin).

Jim

Edit: Looking over the Data Sheets, the unit will run from 3.3 volts, so no need for the inline resistor if you power the GPS module from 3.3 Volts.

Post Edited (hover1) : 5/26/2010 7:10:08 PM GMT

parts-man73
05-27-2010, 01:40 AM
I'm working on a project right now that I utilized this GPS module. Worked nice, and the coordinates I got out of it were within 20-30 feet of the coordinates I received from my cell phone. I was quite happy with the results, as this was the least expensive GPS I have found.

I used with a ProtoBoard was as easy as soldering 4 wires. 3.3v, VSS, RX and TX. I'm not sure how the wires would hold trying to stuff them into a solderless breadboard or the female header on the Demo board.

There are quite a few objects in the OBEX that would receive data from this unit without modification, just type in the pins you are using and go.

What's your project? and what kind of accuracy are you looking for? Mine needs were not necessarily for great accuracy, but repeatability was very important. I'm still testing this module in that regard.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Brian

uController.com (http://uController.com) - home of SpinStudio - the modular Development system for the Propeller

PropNIC (http://uController.com) - Add ethernet ability to your Propeller! PropJoy (http://uController.com) - Plug in a joystick and play some games!

SD card Adapter (http://uController.com) - mass storage for the masses Audio/Video adapter (http://uController.com) add composite video and sound to your Proto Board

hover1
05-27-2010, 02:27 AM
Jeff (Oldbitcollector) has a nice little project at his website:

·http://www.warrantyvoid.us/tiki-index.php?page=PPDB

It uses an LCD as output, you did not mention your intended output, LCD, VGA, TV, SD Card?

Jim

Diego Pontones
05-29-2010, 09:43 AM
Hi, I got a PMB-248GPS receiver module and connected it to a Propeller using the TTL pins. I downloaded a NMEA object and was able to get latitude and longitude right away, however to my surprise noticed that the lat and long although being correct for the location did not change even after I moved for a long distance. If I power cycled the GPS I would then get a new coordinate which was correct for the site but then again it will stay fixed. Suspecting that the parser was wrong I tried with different ones getting the same results. I decided to write a simple parser using the serial objects to just forward the GPS NMEA stream to the serial port and after many tests confirmed that this GPS only updates the coordinates after it is powered up. I can see it is sending new data because I see the time changing in each new NMEA sentence and also the satellite information however the coordinates stay the same as can be seen in the capture bellow (where I was moving). I am thinking that the GPS has a problem and may need to return it but just curious if somebody has seen something similar or I am missing something obvious.
Thanks

$GPGSV,3,3,10,03,05,067,25,22,01,029,*72
$GPRMC,020055.000,A,4518.9667,N,07543.9168,W,0.00, 200.79,290510,,,A*78
$GPGGA,020056.000,4518.9667,N,07543.9168,W,1,07,1. 3,98.5,M,-34.2,M,,0000*53
$GPGSA,A,3,03,11,28,19,17,08,07,,,,,,2.0,1.3,1.5*3 E
$GPRMC,020056.000,A,4518.9667,N,07543.9168,W,0.00, 200.79,290510,,,A*7B
$GPGGA,020057.000,4518.9667,N,07543.9168,W,1,07,1. 3,98.5,M,-34.2,M,,0000*52
$GPGSA,A,3,03,11,28,19,17,08,07,,,,,,2.0,1.3,1.5*3 E
$GPRMC,020057.000,A,4518.9667,N,07543.9168,W,0.00, 200.79,290510,,,A*7A
$GPGGA,020058.000,4518.9667,N,07543.9168,W,1,06,1. 6,98.5,M,-34.2,M,,0000*59
$GPGSA,A,3,03,11,28,19,17,08,,,,,,,2.2,1.6,1.5*3E
$GPRMC,020058.000,A,4518.9667,N,07543.9168,W,0.00, 200.79,290510,,,A*75
$GPGGA,020059.000,4518.9667,N,07543.9168,W,1,05,1. 7,98.5,M,-34.2,M,,0000*5A
$GPGSA,A,3,11,28,19,17,08,,,,,,,,2.8,1.7,2.2*32
$GPRMC,020059.000,A,4518.9667,N,07543.9168,W,0.00, 200.79,290510,,,A*74
$GPGGA,020100.000,4518.9667,N,07543.9168,W,1,06,1. 6,98.5,M,-34.2,M,,0000*55
$GPGSA,A,3,03,11,28,19,17,08,,,,,,,2.2,1.6,1.5*3E
$GPGSV,3,1,10,08,65,238,29,11,62,141,32,28,55,305, 39,07,40,182,*7C