Building a Stevenson Screen

      Any "serious" home weather station should have a Stevenson screen for its instrumentation. This is basically a box with louvered sides, often made of wood, so air can flow through, painted white to reflect sunlight – characteristics intended to make the conditions inside the box as near to the outside conditions as practical while simultaneously protecting instruments from precipitation and condensation.
      Often, less expensive weather stations use "inverted pie plate" radiation shields to protect sensors from rain and sunlight. This is not a practical solution for any system where sensors cannot be separated easily from their data collecting hardware. This is the case with many Arduino-compatible sensors, which are often mounted on small printed circuit boards that contain both the sensor itself and some control and access electronics.
      Unfortunately, commercial Stevenson screens are very expensive – easily costing several hundred dollars. My existing small Stevenson screen was getting crowded with multiple cables, breadboards, and battery supplies so I finally decided to build my own. Commercial wood shutters are ideal components, but they, too, are expensive. Making wood louvered panels from scratch seemed more trouble than it was worth. As a compromise, I bought a pair of two 15" x 36" vinyl shutters from Home Depot. (There are many other suppliers available online. 12" wide shutters would also work, for a smaller enclosure.) I quickly found out why these shutters were inexpensive (~$30): they are just molded vinyl "shells" of shutters, so they required lots of internal bracing with 1" pine lumber. On the other hand, they were easy to cut apart to make the back, sides, and front door. The top and floor are 1" x 12" pine boards glued and joined with 1/2" x 5 corrugated joint fasteners pounded in to pull the joint together.
      The lefthand image shows the partially constructed enclosure, ready for painting the wood parts and final assembly. The parts are held together with #8 x 1/2" stainless steel Phillips head sheet metal screws. Stainless steel screws are more expensive than other choices, but they are worth it because they won't rust. If you can't find them locally, you can get them from an online supplier like McMaster-Carr. The righthand image shows the completed screen mounted outdoors on a garden trellis with some weather station components.