Anyway, this instructable is for the newbies as me which are still experimenting with Arduino, and prefer to program an Atmega168 in Arduino than an AtTyny85 with other methods.
This circuit is based on Mitch Altman's TVBGone and on Ken Shirriff's blog where the software has been modified to match Arduino IC. I then decided to move the programmed Atmega on a dedicated pcb, and make everything fit in a transparent box with a 9V rechargeable battery.
Step 1: Choose the box
My TVBGone uses only a little IR LED, so it shouldn't be much powerful, anyway it's enough to turn off the unwanted tv with ads which had born as mushrooms anywhere in any station here in Milan, the difference is that mushrooms are very quiet...