Last year, I added TMP102 temperature sensors to the Sparkfun Thing boards.
Finally this weekend, I got these posting into Openhab.
I made a reusable library for this, and put it up on github. GPLv3.
It'll connect you to wifi, and then let you send state changes (aka temperature readings) to OpenHab's rest api.
I built one of these up (aka, plugged in a battery) and left in our Sunroom.
The Sunroom in our house has no power, but has many plants growing happy. It's uninsulated and i'd like to know what the temperature does as we go into winter.
I've put the Thing there on a music stand, and it's happily posting the temperature to my openhab every 5 minutes.
The board goes into deep sleep after posting - then wakes up in 5 minutes to post again.