Progress so far - 

Had fun loading up mosquitto & client stuff on a couple of Pi
Got basics working - subscribe on one, publish on the other, woo-hoo! messages.
Got equivalent client stuff on my ESP8266 (after loading arduino IDE and all the other gunge to support that)
Re-wrote weather-sensor server python code (oh yuck. Have you actually seen python? ) to publish instread of using a RESTful server thingy.
Load mosquitto on my mac-mini-server and use that as the broker.

It kinda-sorta works nicely, except after a while (not yet worked out how long) the weather client crashes because the attempt to open up a connection that has worked several hundred times decides to fail. The error message 'socket.gaierror: [errno -2] name or service not known’ doesn’t appear to lead to any readily comprehensible info.

Wild guess right now is something to do with one or other machine going to sleep?

tim
--
tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
Strange OpCodes: COMB: Straighten Wires