LAN Based Weather Station

Weather StationI monitor the weather at Cloudbait with a simple weather station developed by Dallas Semiconductor. The station is based around a series of Dallas chips that communicate over a simple one-wire network. It was developed as a promotional product to showcase the 1-wire product line, and is no longer available from Dallas. It is currently available from Texas Weather Instruments and TAI, although at a rather higher price than the original promotion.

The system works very well, but requires a dedicated computer to read and record the station data. It became inconvenient for me to maintain a dedicated serial port, so I decided to build a standalone controller. Originally, I was going to have this controller read and log the data, which could be periodically read and added to a master log. In the meantime, however, NetMedia came out with a spiffy little Ethernet Web Server module, the SitePlayer. This postage stamp sized coprocessor makes it easy and cheap to get data onto a network. In addition to serving web pages, it is also capable of sending and receiving UDP data packets, and will soon feature telnet capabilities. Since I always have my server running, it provides a perfect interface to my weather station.

ControllerThe system is now in place, and has been operating continuously since May 2001 with no problems. It consists of the Dallas weather station, a Motorola 68HC705C8A microcontroller, and a SitePlayer module. The processor interrogates the station about once a second, calculates raw values for temperature, wind speed, wind direction, humidity, and a second temperature at the humidity detector. These values are placed on a web page and also broadcast system wide via UDP. A client application running on my server (and optionally on any other machines on the network) receives these data packets and calculates average values for display and logging.

In the future, I plan on adding sensors for barometric pressure, moisture/dew, and cloud cover. Rainfall measurement devices are available, but I don't plan on adding one since we don't really have enough precipitation to make it worthwhile.

Here are all the technical details of the project. You are free to use any or all of this information in any way you wish. I'm happy to answer any questions, though I don't guarantee the world's fastest response.


© Copyright 2002, Chris L Peterson. All rights reserved.