Tuesday, January 8, 2008

Replacement Weather Station

At last my replacement weather station has arrives and is in the process of being installed.

It is a Lacrosse 3600 wireless and seems to be working fine except that it is purportedly susceptible to stray RF which there is plenty in the computer room where the base station is located. It has to be reasonably close to the server so that I can connect it to the server's RS-232C port to collect the data. I need to provide a longish cable so that I can move it elsewhere.

The data is here and the graphs are here. They do not look particularly pretty yet and I will be working on the layout. I am also going to upload the data to the Weather Underground, but the data is not loading. I am waiting until the quality issues are addressed and the scripting is finished.

I also need to make a Stevenson Shield to house the temperature and humidity sensor. A rudimentary shield is provided but it is not immune to radiation and it tends to read several degrees high in direct sunlight. In short a Stevenson Shield prevents direct sunlight from distorting the readings by providing a shelter for the sensors. It is no more than a ventilated box but needs to be designed so as to allow the sensors to read the characteristics of the surrounding air without bias from the radiant heat from the sun or the influence of surrounding structures. I have been looking at shield designs and most people tend to use layered rings from largish white or painted flower pot bases. From what I can see these may be more or less successful bur are never as good as the louvered wooden boxes as seen in the official weather stations. I have searched unsuccessfully for blueprints for one of these so it looks like once again I will be designing and building one from scratch. I will try to remember to take progress photos for reference and to assist anyone else who wants to make their own.

I will post some pictures for the voyeurs amongst us later.