GPS data transfer

[tinkeringtech]

I want to be able to move the GPS data captured from the GPS shield to the SD logger shield. The primary reason being that I want the SD logger RTC timestamp capabilty to be present when there is no fix. I'm also getting a couple of analog sensor readings on the SD shield. Essentially, I only want the latitude and longitude data transferred onto the SD logger shield so that everything can be logged in one place, on one card. Is there a way to do that?

I'm guessing perhaps something to do with the TX RX pins on the SD logger arduino connected to the GPS logger. Apologies if the intention is not clear. Thanks.

[adafruit_support_bill]

You could wire the GPS to the logger using SoftwareSerial, or get an RTC breakout board to add a clock to the GPS logger.
http://www.adafruit.com/products/264
http://www.adafruit.com/products/255

[tinkeringtech]

You could wire the GPS to the logger using SoftwareSerial...

Is that without the shield, just the EM-406A? If yes, can the 2 serial pins on the EM-406A go to the SD logger arduino's pins 2,3 for example? Something like this http://wiring.org.co/learning/libraries/nmeasentence.html

[adafruit_support_bill]

I believe that the EM-406A is a 3.3v device and would need a level-shifter for the Rx pin as on the GPS shield. All things considered, adding an RTC breakout to the GPS logger might be the easier path.

[tinkeringtech]

Thanks. I agree that it will be easier just to throw in a RTC device, however since this is a team project with budget issues, I'm trying to avoid purchasing more hardware. Is there a way to access the level-shifted GPS data from the GPS logger and inject that into the SD logger arduino? I also have a working cellphone module shield on the SD logger that I would hate to have to migrate to the GPS logger.

[adafruit_support_bill]

If you power the GPS shield by running jumpers for +5v and GND, you can just run the GPS signal jumpers from the GPS shield over to the Logger shield.

[tinkeringtech]

Thanks. Something seems a little off when I use the GPS CSV logging sketch http://www.ladyada.net/make/gpsshield/GPS_CSVSensorLogger.pde so that I can log the analog sensor values. I uploaded the sketch and opened the serial monitor and this is what I got. It stops after printing out the lines below. Ths SD card on the GPS logger has GPSLOG03.TXT in it, but completely blank. I did change #define isdigit(x) ( x >= '0' && x <= '9') to #define digit(x) ( x >= '0' && x <= '9') because of a compile error that I was getting. I read in a forum that renaming the isdigit would resolve the error and it did. No clue why its not working.

GPSlogger
writing to GPSLOG03.TXT
ready!
time,lat,long,speed,date,sens0,sens1,sens2

$PSRF151,1*3F
$PSRF103,4,0,1,1*21
$PSRF103,3,0,0,1*27
$PSRF103,2,0,0,1*26
$PSRF103,0,0,0,1*24

FYI, the GPS basic logging sketch https://github.com/adafruit/SD-Basic-GPS-logger worked fine and was logging the data correctly along with the correct lat and long. Thanks for any help in getting this working.

[adafruit_support_bill]

Is this with just the GPS logger shield, or with both shields connected?

[tinkeringtech]

Is this with just the GPS logger shield, or with both shields connected?

Just the GPS logger

[adafruit_support_bill]

Is the output always the same? Or does it get stuck in different places?

Check your serial connections for the GPS module and make sure they are solid.

[tinkeringtech]

I don't think the connections are an issue as it worked with the basic logging sketch just fine with the same connections. The Arduino serial monitor gets stuck at

GPSlogger
writing to GPSLOG03.TXT
ready!
time,lat,long,speed,date,sens0,sens1,sens2

$PSRF151,1*3F
$PSRF103,4,0,1,1*21
$PSRF103,3,0,0,1*27
$PSRF103,2,0,0,1*26
$PSRF103,0,0,0,1*24

and it stays there. Does not change. I noticed that the CSV code is listed under the "older" code. I'm using an UNO with the AF_SDLog library installed. Wondering if there is some sort of conflict that the AF_SDLog library may be having with the new SD library built in to arduino-0023.

[adafruit_support_bill]

Looks like it is making 5 passes through the loop then stalling. And the file is created but empty. I suspect that SD library is filling up a buffer then hanging up while trying to flush it to the card. As you say, it could be a compatibility issue with the older code. The author of the library is a regular here. Maybe he can shed some additional light on the subject.

[tinkeringtech]

The whole reason I had started looking into the older CSV code listed on the site is to utilize the built-in analog sensor logging capability. If there is an alternative GPS logger code with the ability to log analog sensor values, I'm all ears. Not a coding guru, hence the reason not wanting to try and create something from scratch

[adafruit_support_bill]

There are others who have done similar projects with both GPS and analog data. If you search the forums you may find some examples that are useful.