The WMR918 Weather Station

I started my experience in weather stations with a WX200 and the code written by Tim Witham <> called wx200d. I got the job of porting the code to an SGI O2 located somewhere at a military installation, which was basically really easy.

I next came across the WMR-918 wireless system, which costs a lot more but doesn't need wires running all over the place. The downside is, of course, that the 'R' in the model means it talks a completely different protocol than the WM918.

The protocol isn't tough. There are some status bytes that are a mystery, but most of the data is easily decoded. There are still gaps where the optional sensors must show up somehow, but I ain't got any so I don't know where. Here is the spec.

And now the real prize, software to talk to the WMR-918 on UNIX. I wrote this code on an SGI running IRIX 6.5, but I have compiled and run it on a Linux 1.2.3 system. The only problem I found on the Linux system was that the 33MHz 386 appeared to lose bytes in input.

This is version 0.1, so there is no Makefile or fancy installation. 'build' is a list of the gcc commands to compile the daemon. You will need to edit the perl code to set the location of your local perl. Some of the code is rather crude, but shows how decoding can be accomplished.

Updated: latest version as of 12 Sept. 2000. I've included perl code to do plotting of data using plotxy, and an html directory of programs to create a simple web page with graphics.

Before you can use this software, you must answer a short quiz:

  1. Why should I buy anything from Oregon Scientific? Answer.

This page last updated: 12 Sept 2000