I'd like to build a system that allows temperature to be monitored at a dozen different locations simultaneously and recorded/logged at a central arduino node via some form of wireless communication.
I'm looking to build a number of battery operated wireless temperature sensors that can communicate across about 20-30meters to a single receiver. I only need one-way communication, and I don't need to send much data. (also, the data will change only very slowly)
I know I could use one of the wiFi arduinos, but to be honest that's overkill for my needs and probably too expensive. I probably need 10-12 sensors, so I really need to keep the costs down, what are my options?
Currently I'm thinking of an arduino pro-mini with a TMP35 temperature probe to gather the temperature (total cost about £10) but then I need some method of transmitting that data back to the central node.