This is probably the most tightly budgeted version of moving towards a home sensor network. After comparing few real IP network solutions (and after testing one in our research project), I decided to stay away from them and rely on cheap consumer electronics to do those individual tasks that we need. Thus, to measure temperatures and moistures from various parts of our house, I got a weather centre from Clas Ohlson (a Nordic electronics chain) and few extra wireless sensor units. This particular model (UPM, model number 36-2384) can take four external sensors, all equipped with temperature and humidity sensors. And how to know what is the temperature in sauna? Clas Ohlson comes to help, again. Just pick up a wireless pair of oven thermometers (model number 34-6723), and there you go. And you have various alarm functions build in, too. But no centralised controls, full log files, remote controlling or other such sweet IT things, of course.
frans goes blog 