
Originally Posted by
oj88
Yup. It's an active GPS receiver. It needs 5V power from the DVR and it sends back GPS coordinates using serial communications (ie. NMEA 0183 protocol). The memory backup battery is a dead giveaway. The memory serves to store ephemeris data and whatnot.
No I haven't tinkered with it. Like you, I also temporarily disconnected the GPS module.
I've thought of using a relay as well, one which can be triggered by the DVR's backlight circuitry or the power LED. The thing is, I'm not sure if the 3.7V LiIon/LiPoly battery will be enough to energize the 5V relay. In that regard, I think that a solid state approach is preferred (smaller package and lower power draw). I just haven't found the time to design the circuit yet.
But do tell if you make any developments.