Advanced thermostat

Hi all,

Before I begin, I just want to say I've searched this forum for thermostats and found lots of info, but non of it fits my needs. I'd like to build an electronic thermostat for a wide temperature range (-10C to +30C) with independent control over switch on and switch off temperatures. A display would be nice, but it's not a must. Any help would be much appreciated. Thanks.

Well I expect to have a kit ready this summer...
**broken link removed**
The Cricket Thermostat (RS485 & Humidity not shown)

That looks like one of those 1F supercapacitors; what purpose does it serve?

It's actually gone on the current prototype, a HS1101 humidity sensor takes its place. It was to test a simple two diode battery backup, it worked but a set of 3xAA batteries instead ran it for months. It's up in the air if I'll add the battery / cap backup to the final design.