rgm2000hack

Royaltek RGM-2000 – HACK

Because I was asked to develop a tracking-device for a bycicle, I was searcheing for a *very* cheap GPS-Module. After googling a bit, I found a ‘GPS-Antenna’ called Royaltek RGM-2000. It was sold as an antenna (for some discounter navigation system), but it contains a fully equipped SiRf?-Star-2 GPS Module with NMEA-0183 output.

I got mine at ebay for about 10 bucks, so it _IS_ really cheap.

Hacking.

Step 1

Strip off these silver stickers on the backside of the RGM:

Step 2

Strip these two (red marked) screws:

• >

You should now be able to open the module:

Step 3

Now find the two screws which hold the PCBs in place. They are situated at the opposite end of the Module (compared to the cable-Output):

Get rid of them!

By now it should be possible to seperate the module from the ground-plate. However, the Magnets in the ground plate attract the shielding, so you may need some force…

Thats it! Make sure to save the neodymium magnets!

Pinout

This Image shows the modules BACKSIDE! The cable-colors may be different for your Module. you can find the GND-Pin by checking wheather the pin is connected to the shielding of the circuty (NOT the top antenna) using a continuity tester (!).

Pin-NR.	color (in Pic)	usage
Pin 1	red	+VCC 5V DC
Pin 2	black	GND 0V
Pin 3	yellow	TxD Data as NMEA-0183; 4800:8N1
Pin 4	white	usage unknown.

Output

The Module is transfering data according to the NMEA-0183 protocol (4800bps, 8 Bit, no parity and 1 stopbit). How that works you can read HERE.

Excample-Dataset (no GPS-fix):

Have fun !