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By Papps

I am doing a school project so I am kind of new to electronic design so please excuse my ignorance on terms used.

I am basically looking to build a extremely small, long range GPS tracker. My goal is to use something like a Sirf III chip and send the NMEA data to a Bluetooth enabled phone. The problem is that I would like to have more distance than the 100m class 1 transceivers. I would actually like to go about 250m.

The obvious solution for a long range GPS tracking device is to use something like a GE863 module. But do to space requirements on my tracking device, this is not a viable approach for me.

As I would like this to be extremely small and long range, I was thinking of using something like the RF-24G with a Sirf III chip for the transmitter. I would then have another device, on the bluetooth cell phone equipped person, which could then take the data from the RF-24G and somehow convert it to bluetooth data and use a class 2 bluetooth device to send it to the bluetooth enabled phone. I also only need communication from GPS tracker to BT enabled cell phone, not the other way around too.

I am basically wondering if this design seems possible. Or, does anyone else have any suggestions? My restriction is that the PCB area must be less than 1000mm^2. The battery would be seperate from this board space. I also am willing to design and build a custom board for this application.

Also, if this design is possible, could someone please point me in the right direction for interfacing of these modules on the transmitter. Basically I mean, do I need to somehow interface the NMEA data or Sirf binary data from the Sirf III chip to the RF-24G by using a microcontroller or something? Similarily, how would the interfacing be done between the data received by my receiving RF-24G to the bluetooth transmitter (which transmits to the bluetooth phone). I would guess this data would still be in NMEA format, so I would somehow need to change from NMEA to bluetooth.

I know this was a little long winded, but I would appreciate any help anyone could give me!!
By denisbest
Well, I think simply it should look like GPS ---(NMEA text)---> RF chip ---(NMEA text)---> RF at the other end ---(NMEA text)---> Bluetooth. Your data is plain text, RS232-friendly, at any point of time. You do not have to convert it anywhere at all. You can get DIP boards with GPS, RF and Bluetooth modules from SparkFun and it just the matter of interfacing all these boards to a microcontroller on the breadboard.

You need:
- Programmer for microcontroller and microcontroller itself
- Find C or Picbasic compiler and learn how to use it
- 1 x GPS board
- 2 x RF boards
- 1 x Bluetooth board
- (optional) LEDs, resistors, capacitors, other stuff like that.

When you developed a prototype, you can design your own board (Eagle rocks) with bare components, SparkFun has wonderful tutorial how to desing boards.
By Papps
Excellent. Thanks for your reply.