Can a Garmin GPS be turned into a DIY tracking device?

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Discussion Overview

The discussion revolves around the feasibility of converting an old Garmin GPS device into a DIY tracking device. Participants explore various methods and challenges associated with real-time and non-real-time tracking, as well as the technical requirements involved in such a project.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • Some participants suggest that the Garmin GPS is a passive device that only receives signals, indicating that it cannot transmit location data without additional hardware.
  • One participant proposes encoding GPS output onto an audio signal for transmission via cellphone, while noting the need for a power source for the cellphone.
  • Another participant mentions the use of HAM radio for tracking, specifically through the Automatic Packet Reporting System (APRS), which requires a HAM radio license.
  • A suggestion is made to solder into the data lines of the Garmin to log coordinates, although this would not provide real-time tracking and would require significant effort.
  • Some participants express interest in building a homebrew GPS system, acknowledging the complexity of such a project.
  • There are mentions of alternative tracking devices, such as Progressive insurance's SnapShot modules and GPS modules from Sparkfun, which may offer simpler solutions than modifying a Garmin device.
  • Discussion includes the potential for using pre-paid cell phones for anonymous data transmission via SMS.

Areas of Agreement / Disagreement

Participants generally agree that while it is theoretically possible to create a DIY tracking device using a Garmin GPS, there are significant technical challenges and limitations. Multiple competing views on the best approach and feasibility remain unresolved.

Contextual Notes

Participants note various limitations, including the need for additional hardware for transmission, the complexity of hacking a consumer device, and the potential for anonymity issues with commercial tracking solutions.

Who May Find This Useful

This discussion may be of interest to hobbyists in electronics, individuals exploring DIY tracking solutions, and those interested in GPS technology and its applications.

Flyingwing12
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I was looking through some recent catalogs from electronic stores and a new thing they are trying to hitch is the GPS car tracking devices. There is a major flaw in the system for anonymity, you have to register with a " air time" service to add tracking days and such.

For 139 dollars I was intrigued. I remembered I had an old Garmin Gps that I used to walk around the mountains.

Would it be possible to turn that into a tracker that could be pulled up on a computer screen or something?

I think with a little know-how it can be done.

No doubt this will get flagged for illegal activity discussion.

At least they keep this place clean.
 
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As far as I understand the Garmin GPS is completely passive. That is, it receives signals from several satellites and gives you your lat/long. There is no signal transmitted, and there is no way a passive receiver can be detected.

In order to track a moving object (car, for instance) it would be necessary to transmit something to get detected by the satellites or other fixed receivers.

Cheers,
Bobbywhy
 
If you need to do the tracking real time, it gets a little messy. You might have to encode the GPS output onto an audio signal and transmit it by cellphone. (You'd need a way to keep the cellphone's battery charged.)

Non-real time tracking would only require a way to store the time and data on a memory chip.
 
Flyingwing12 said:
I was looking through some recent catalogs from electronic stores and a new thing they are trying to hitch is the GPS car tracking devices. There is a major flaw in the system for anonymity, you have to register with a " air time" service to add tracking days and such.

For 139 dollars I was intrigued. I remembered I had an old Garmin Gps that I used to walk around the mountains.

Would it be possible to turn that into a tracker that could be pulled up on a computer screen or something?

I think with a little know-how it can be done.

No doubt this will get flagged for illegal activity discussion.

At least they keep this place clean.

This is done with HAM radio all of the time. It's called APRS, and you tie your GPS to your HAM radio -- your position is sent via HAM radio to whatever tracking software you choose to use. It's very handy when you have a bunch of HAM radio operators helping with bike races and similar events, spread out over the countryside:

http://en.wikipedia.org/wiki/Automatic_Packet_Reporting_System

You need a HAM radio license (and APRS-capable HAM radio), but that's easy to get now. There may be other ways to accomplish what you want, without using HAM radio, though.
 
The GPS coordinates probably spit out of the GPS receiver inside your garmin on a USART unless the receiver and microcontroller are combined. You could solder into these data lines and record/parse the data with a microcontroller, and then later download it onto your computer with some serial interface like USB. You might also need to disable battery saving features in the receiver since the Garmin microcontroller will be communicating with it. You would have to power it all with a battery. It won't be real time and will require some significant effort, but it will log coordinates. If you want remote real time access, the HAM radio idea is good or use a gsm modem that downloads to a server like the device you saw probably has. With all of that effort, you probably would save time and money just buying what they made or designing your own device.
 
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I don't know how feasible it is to hack a Garmin but it is possible to build a completely homebrew GPS. Personally I found this fascinating. It's definitely not a project for the feint of heart though.

http://www.holmea.demon.co.uk/GPS/Main.htm
 
Or try to get a hold of one of Progressive insurance's SnapShot modules.
 
es1 said:
I don't know how feasible it is to hack a Garmin but it is possible to build a completely homebrew GPS. Personally I found this fascinating. It's definitely not a project for the feint of heart though.

http://www.holmea.demon.co.uk/GPS/Main.htm

You can buy a lot of that stuff integrated on an IC. The front end and everything to the interface to your digital circuitry comes in hybrid packages from companies like Trimble. You just have to design the antenna trace impedance mostly and then your FPGA/whatever. So, that at least would be 1 short cut.
 
The trick is the communicaiton channel - HAM works, but I do not know how small of a HAM transmitter you can get. I think cell phones actually can be anonymous if you buy a pre-paid one - then send data via SMS.

Also - Sparkfun has a bunch of GPS modules and a small arduino - may be easier then hacking a consumer device.

Etherway - this can surely be done, but will involve working on a number of different things...

An interested related project...http://www.chriscoldewey.com/2008/05/11/tracking-deer-on-google-earth/
 

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