AladdinWeather

From GumstixWiki

Intro goes here. Note that we finished working on this project on 28/09/2007. The source for this project is available on ugforge at this URL, or from Dr Alex Rogers: https://ugforge.ecs.soton.ac.uk/projects/situation/

Contents

Completed Goals

Sensor Integration

This was achieved through an nmeap parser on the serial interface which then writes to two files. There was some work on writing to an RDF database, but we were unable to test it on the target due to compilation issues which were not solved till the end.

Serve RDF Data

The lightweight webserver serves RDF with no problem. As far as it's concerned it's just a static file. We did have to add the rdf mime type to the /etc/mime.types list.

Implementation

Modifying 485PTBR Baudrate

The Airmar PB-100 Weather Station outputs serial data using rs-485 but the gumstix serial ports support only rs232. The 485PTBR serial adapter was used to convert between the two standards.

This adapter is by default setup for 9600baud but needs to be modified to run at 4800baud required by the weather station. This can be done by removing resistor R3 and putting a 200K Ohm resistor on R2 identified in the 485PTBR Datasheet.

485PTBR to Gumstix

The following color coding is used:

  • Rx = Orange
  • Gnd = Brown
  • Tx = Green

PB100 to 485PTBR

Signal names taken from 485PTBR Datasheet and the wire colors are from PB100 Installation

  • TDA = Yellow
  • TDB = Orange
  • RDA = White
  • RDB = Blue
  • +12V = Red
  • SG = Black

Goals in Development

SPARQL Endpoint

This goal was hampered by cross compilation issues with the librdf libraries, we made some progress but unfortunately only in the last 2 days. See the sparql-endpoint.c file.

The problem stems from Pro Police a stack smashing detection system in GCC, disabling stack smashing detection when creating the cross compiler will allow cross compiling the RDF libraries