The next device is ready... ;) It is the TSL230R light sensor.
It prints out the Lux value every N seconds.
My code is based on this Blog entry. You could buy the sensor at Sparkfun where you will find the Datasheet too. Another place for code is here. There is provided a modified version of the link above.
My first Arduino device is born. Thanks to John! He learned me how to develop the driver for it. It is a DS1621 temperature sensor with 2-Wire (I²C) interface bus. And, YES! I have currently 17.5 degrees in my room.
I am impressed! The code will follow ASAP!
Since i am not lucky with the original LEGO NXT programmable brick because I need the programming environment provided by LEGO. Sure, there are nice implementations of alternative firmwares around the web but none of them are what I want. Sometimes they are using ugly languages like Java and sometimes the code for the firmware is not public available.
Now I have my solution. Move the LEGO NXT brick to your trash and build one by yourself using Arduino based boards.