Air conditioner controller (fan)

Greetings, Habr!
Finally I decided to write about my small development. The car has an air conditioner (not to be confused with the climatcontrol), we press the button on the panel, the air conditioning system is turned on and the cooling system blows from different slots of the cooling system sharashit (which, among other things, install) air. I have long wanted to automate this process. There are several factors here: a constantly working air conditioner is not very healthy, you can overcool and not notice, gasoline consumption increases, the car pulls worse, etc. Who cares, I ask under the cat ...

The idea was as follows, to develop a “two in one” device: 1. A car clock with a 24 hour time format (yes, that was the main thing). 2. Air conditioner controller. In my Lancer there is a regular clock and in their place an 8x2 LCD display perfectly fits (I used on the popular HD44780 controller - indicator WH0802A).
Developed a scheme for atmega8, spread a signet:

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

The longest time was tormented with the logic of triggering and tripping, entering trigger thresholds, etc. Code wrote on CodeVisionAVR. I wanted to give a piece of code as an example, but I do not know which one. The whole - a lot, but in pieces, and so everything is clear.
After assembly it turned out:

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

The controller is set to the required temperature, the cooler blows to the temperature sensor (DS18B20), it cools down, the cooler turns off. To make it clearer on the video thresholds set smaller. For better temperature measurement, you can install several sensors in different places (the sensor protocol 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 will say that I never installed a device in the car, but I am planning.
Be creative!