Standard firmware and GPS data

Friday, September 14th, 2007

As I posted yesterday, Antonio Scarfone made a NXC code that managed to read a Bluetooth GPS textual (NMEA-0183 format) readout. I’ve tried the same thing long ago, but for the reasons listed below dropped this project thinking it is impossible…
Why did I think so? Well, the Bluetooth SDK describes in the end of Appendix 1 (Communication protocol) the structure of the “expected” ‘data packet’ - 2 byte packet size, command type byte, command byte and data. This is very different with NMEA format which starts with e.g. $GPGGA and ends with *XX\LF\CR (XX is a 2 char hex checksum, \LF\CR are line feed and cartridge return chars). For me, and many other AFOLs this inconsistent format seemed impossible to overcome with the standard LEGO firmware. Other firmware like pbLua (and soon RobotC) have BT ’stream-mode’ where program can deal with the BT port like simple serial port. GPS communication with pbLua was reported a while ago, and Steve Hassenplug recently converted his Green Monster to use GPS with RobotC. But using GPS with NXC or NXT-G? I thought it will never happen.
All this was true till Antonio’s code came about. I’ve spent several hours looking at the code and going over the firmware source files trying to understand how this works. Here’re my preliminary conclusions. (more…)

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NXT-G support for Power Function

Friday, September 14th, 2007

I’ve asked mindsensors.com regarding NXT-G support of PF motors via their NR-Link. Indeed, the NR-Link can remotely (via Infra-Red) control PF motors. Here’s their reply:

NXT-G block for NR-Link, has groups of macros for RCX/Train/PF motors. From the ‘Action’ pulldown, select the device you are going to talk to, and from the ‘Macro’ pulldown choose appropriate macros.

The NXT-G blocks are located here.

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