I've got a small bluetooth gps receiver based on the ngr-531 chip, that I'd like to connect to my arduino mega to receive nmea data. I'm a total newbie on electronics in general so forgive the silliness of my questions. First, I've found the ngr-531 chip specs here:
and thought that pin 7 and 8 (TXA and RXA), on page 8/15 of the manual, had to be interesting: I've carefully hot glued two wires on these pins and put them into my arduino mega pin 0 and 1 (RX and TX), then I've opened the NewSoftSerialTest sketch, modified the second line
and modified all baud rates to 9600, and finally I've loaded the code into the arduino. The gps receiver gets power out of its own battery (3,7v Nokia battery) while the arduino is powered by my laptop usb port, so the tx and rx wires are the only connection between them.
Once the code gets loaded, the serial monitor shows the code greeting message "Goodnight moon!", and nothing else. I've made a couple of tests, swapping the wires and playing with the baud rates, but still nothing comes out of the gps receiver (which is supposedly good for it's the one I use from time to time with my nokia n70 tomtom). Here are my questions:
- am I making things too simple by thinking that just hooking the gps chip TXA and RXA to arduino's RX and TX would do the trick ?
- do I need to connect the arduino and gps receiver grounds together ? (actually it was one of my tests, but when I did that I got a sync error from the arduino software when loading the code)
- do a gps receiver usually send out serial messages while trying (and not succeding) to get a satellite link ? I'm asking this because all the tests have been done in a office room, with no clear path to the sky, and the receiver had probably not been able to get a satellite link.