All of the commercially-available Stevenson screens that I could find were usually too large for my need and were always too expensive. My first attempt at providing weather protection for temperature and humidity sensors involved a short piece of plastic waste pipe but it proved to be no good. Humidity, in particular, would rise unti it was off the scale.

I wasn't keen on using upturned plant pot saucers so my second attempt uses an idea adapted from here: Cheap Plastic DIY Stevenson's Screen. Total cost for the screen was less than 5 UKP - for four louvred vent panels from ScrewFix.com.

Begin by cutting the two ends off each panel and cutting each panel in half. The louvres on one piece of each panel will be held firmly with vertical supports but, on the second piece, the louvres will only be attached on one side. Don't discard these pieces - they are used for the internal louvres.

Fix two pieces of 20mm x 20mm wood to the top and bottom of the first piece and attach the second piece by screwing into the end of the wood. Trim one of the off-cut louvres to size and glue it to the inside of one of the sides. Make sure the louvres point downwards, the same as those on the outside so they form a '^' shape.

Trim another louvre off-cut and glue it inside the second side. This photo shows three sides fitted together, each having its inner louvres glued in place.