Some projects that I'm working do not require more than three I/O pins. Arduino UNO and even the Arduino MINI are little more than I need. I need less than 5 I/O pins, using internal clock, small, cheap and easy to program > Arduino IDE. So, I found the ATTIny13 and this website provides the step-by-step instructions how to program the ATTiny13 using Arduino's IDE with AVRISP MKII.
I used the smeezekitty's core13 library. But I used the core13_018 version and no luck with the latest core13_18_5. Not sure why the latest version doesn't work on my PC. Anyway, this will open the door to my many other mini projects that doesn't require a lot of I/Os and cost. Mainly my reason is that I have a handful of surface mount type ATTiny13 lying around from my previous project.
My first project with ATTiny13 will be for display board running lights. To connect to AC230V incandescent bulbs with speed control and blinking modes. Will use triacs, optoisolators and voltage regulator for this project. Will post up in my blog when is ready.