Air conditioner (fan) controller

Greetings, Habr!
Finally I decided to write about my little development. The car has air conditioning (not to be confused with climate control), we press a button on the panel, the air conditioning system is turned on and cold air blows from various slots of the cooling system, which, in other things, install it). I have long wanted to automate this process. There are several factors at once: a constantly working air conditioner is not very good for health, you can overcool and not notice, gasoline consumption increases, the car pulls worse, etc. Who cares, please, under the cat ...

The idea was to develop a two-in-one device: 1. A car watch with a 24-hour time format (yes, that was the main thing). 2. Air conditioning controller. In my Lancer there is a standard clock and in their place the 8x2 LCD display perfectly fits (I used the WH0802A indicator on the popular HD44780 controller).
He developed a circuit on atmega8, parted a signet:

In addition, a separate small board is a clock module on the DS1307 (I took a quartz with capacitors for greater stability from the motherboard).

The most tormented with the logic of operation and shutdown, input thresholds, etc. The code was written in CodeVisionAVR. I wanted to give a piece of code as an example, but I don’t know which one. All - a lot, but in pieces and so everything is clear.
After the assembly, it turned out:

Later I put another LCD - the one in the first photo (the test was 16x2).
The
operation of the device can be viewed on the video at the link: dl.dropboxusercontent.com/u/25037786/habr/Cond/VID_20130221_190747.3gp
or on youtube:

The necessary temperature is set on the controller, the cooler blows on the temperature sensor (DS18B20), it cools down, the cooler turns off. To make it clearer on the video, I set the thresholds less. For better temperature measurement, you can install several sensors in different places (the protocol of sensors allows them to be parallelized). Instead of a cooler, we connect to the on / off button of the air conditioner and enjoy the constant temperature in the cabin. Everything is simple - everything works. In fairness, I’ll say that the device has not been installed in the car, but I plan to.
Do it!