This view shows the completed Weather Station board (bottom) with its companion Radio Modem Transmitter board connected.

The radio modems presented in the November 2003 and May 2004 issues have proved to be very popular and it’s been an education to see some of the uses they have been put to. One of the most common FAQs concerned the monitoring of weather, so in response to what is clearly a widespread fascination, I’ve decided to produce a simple weather station design.

Educational value was a major consideration, so I decided that the best arrangement would be to have a PICAXE-18A handling all of the smarts. This would be followed by a serial data modem (from the November 2003 issue) that simply relayed the various readings to a receiving station, where they could be displayed. The avid experimenter or student would then be able to poke around the sample code to their heart’s content, secure in the knowledge that they don’t have to worry about messing up a complex RF data link.

A computer is one of the easiest ways to present the readings, so the results go into the COM port of an old IBM-compatible running Hyperterminal. Fig.1 shows the basic layout.