Code entry to your garage using a doorbell and an attiny13 via HaD. Mike writes -

I wanted to use an ATtiny13 microcontroller because I had ordered a half dozen a few years ago and still had most of them sitting around. This meant I would need to fit the code into less than 1024 bytes of programming space. I downloaded Alan’s code thinking it might be in C but it turned out to be BASIC so I decided to write my own from the ground up. I did start with my favorite Danni Debounce code (written by Peter Dannegger) to handle the button presses and coded a prototype using an ATmega168. Here’s how it works…