The solar powered, bluetooth-enabled temperature sensor is almost done. I spent a couple of hours soldering most of it up yesterday, and there are only a couple of parts missing before it's ready for launch.
The solar panel will recharge a 9 volt battery, which in turn powers the circuit via a regulated 7805-based 5 volt supply. The micro controller is an ATmega88PA this time, on a DIP adapter - on a socket. I also added a convenient ISP socket, to ease future programming.
A connector plug will be placed just above the caps for attaching the solar panel.
The top half consists of the Bluetooth module and an LED which will give a quick flash to indicate that the controller is out of sleep.
I've only confirmed that the ISP works so far, so today I'll start writing the communication software, sketching up a simple protocol and maybe even toss in the divider circuit - if there's time.