SparkFun Forums

[JibberJim]

I really want an SD writing GPS logger, and the Lassen evaluation kit is perfect, but for one thing - I want Sirf Star III, is it possible to simple swap out the Lassen IQ with one of the Sirf modules? It seems not.

What would be involved in creating the same functionality with one of these units rather than the lassen?

Any info would be very useful!

Cheers,

Jim.

[ohararp]

Working on something very similar for myself...I'll keep you posted on how it goes.

[Jcrosby]

I am looking for the same thing. I am currently doing some research on this device:

http://www.hobbyengineering.com/H1613.html

I am hoping that I can connect one of sparkfuns GPS modules to this device with a small micro controller circuit.

[ohararp]

J, have you ever used PICBASIC? check out www.picbasic.org (UK VERSION - DO NOT BUY US). The compiler supports an SD_FILE System, one of the users has created a FAT16 library. This is what I plan on using. If you are interested I could supply you with additonal pcb's when I get things running. I am working on the schematics as we speak. I have read/write to SD memory already and this app should be pretty simple from a code stand point.

I also meant to add that will be incorporating a usb charging scheme and a lithium ion battery. Looking at ~800-1000 maH at 100mA draw for a run time of ~8-10 hours.

[Jcrosby]

O, I have never used PICBASIC. To tell you the truth I am very new to this. Why wouldn't I buy the US version? I am very intrested in your pcbs, tell me more.

[ohararp]

Here is the schematic layout of the board. This board will be my first all smt board, so I am pretty excited. I just have to wait for my parts to come in from sparkfun before I finalize the design. I want to make sure all the smt pads and what not will work. Basically, the board manufacturer that I use www.pcbfabexpress.com requires a minimum order of boards (5). If you are interested I could source enough parts minus the gps to build up a board for you. You could pay me cost for the parts and board. I am planning to use a microchip 18F4620 to control this device and an MELABS serial programmer to reprogram it.

[/img]

[Jcrosby]

O, shoot me an email at

[MySparkfunUserName]41@cox.net

[ohararp]

This is the gps data logger that I designed just recently. I just got the first one assembled. The EM406 gps uses the latest SIRFSTAR III chipset to make sure you get a signal in areas of dense foliage, canyons, and even inside buildings depending on the construction technique. Battery is a 3.6V lithium ion type large enough to provide 22 hours of continuous operation and can be replaced with a fresh battery or charged/powered via a usb port at 100mA. The SD memory card can be as large as 2GB and up to 255 files can be on the card at a time. The time and date of each file is also recorded when the file is created and updated. Recording options allow for direct recording of NMEA output from the gps or processed data in the form of LAT,LON,ALT,HDG,SPD,SAT,FIX,Hours,SD_Minutes,SD_Se conds,SD_Day,SD_Month,SD_Year. Either option is configurable via a CONFIG.TXT file. The contents of this file are below.

4800,1,11111111
‘BAUD,INTERVAL,OPTIONS
‘BAUD OPTIONS (1200,2400,4800,9600,19200,38400)
‘INTERVAL OPTIONS (0-65536) SECONDS
‘NMEA MODE[7]=0 (MODE[7] NC[6] GPVTG[5] GPRMC[4] GPGSV[3] GPGSA[2] GPGLL[1] GPGGA[0])
‘KML MODE[7]=1 (MODE[7] LAT/LONG[6] ALT[5] HDG[4] SPD[3] SAT[2] FIX[1] TIME/DATE[0])
‘BIT[X]=0=OFF BIT[X]=1=ON



The first line is what actually configures the device. You set the baud rate (communication setting), recording time in seconds, and finally a 1 (on) or 0 (off) for the options of the two different recording methods. It’s really easier than it seems. The device defaults to the setup you currently see. You can “tweakâ€

[michaelm]

The GPS logger you designed appears to be exactly what I am looking for.

I tried the Earthmate Blue GPS logger and found it to be unreliable.
I then started experimenting with the Spark Fun GPS datalogger, and
while it proved to be much more reliable than the Earhmate, it is
limited in its available options. I had to purchase the evaluation
board to set the NMEA sentences I was interested in(GPGGA, GPRMC).

Does your logger have an indicator to show logging activity? Valid log indicator?

Looking forward to hearing when this goes into production and is available.

[JibberJim]

Nice looking device! definately keep me posted - email to jim@jibbering.com it far and away looks like the best device seen so far for www.openstreetmap.org work.

[ohararp]

All, since this board ws the first transition from development board (LABX1 and breadboard) to actual layout I wanna make sure everything transitions smoothly in my code. So far everything is working out allright. I am putting up finishing touches on the website and webstore over this 4th of July holiday. I am also expecting a batch order of em406's in from usglobalsat shortly. Expect availibility around the 15th of July.

Michael, the em406 has an led that acts as a power inidicator at initial start (steady red) and begins to blink in 1 second intervals when a fix is made. My pcb has 3 leds: 1. USB charging (shuts off when charging complete) 2. NMEA_LED blinks when all "config option" messages have been received and the data is written to the board. 3. KML_LED blinks when all "config option" data has been computed and is being written to the board.

I am going to add an additional Config option to the source code that will allow for logging of data where:

If you set the option to "1" it will only log data when a fix has been made
or
If you set the option to "0" it will log data regardless of whether the gps unit has a satellite fix.

I have used the sparkfun device and hated the fact that google earth would blow up when 0000.0000 was written to the lat/long locations. Hopefully, this will alleviate some troubles for people.

[ohararp]

the latest and greatest on this project can be found at:

http://sdgpsdatalogger.blogspot.com/

[kaiki]

Do you have a larger sized picture of the schematics, i can't really make out any of the details on the one posted ?

[ohararp]

I updated the blog with a higher resolution file. This can also be found at:
http://rapidshare.de/files/26986577/GPS ... D.BMP.html

[kaiki]

Thanks for the schematics..

Just FYI if you save as JPG (Grayscale mode and quality around 10%) you will still get an excellent quality (same resolution) albeit smaller sized image (200kb for the image you posted)
The rapidshare thing kinda sucks!