This all started when I was 12 and decided to build a binary clock out of 7400 logic on a breadboard. It worked, but I never built it into a proper project. Until now.
I focused a lot on software development, neglecting the hardware side a bit. But recently I visited my local hacker space, caught the maker bug, and started drawing circuits again. Here's where I'm currently at, after a few months of playing with Eagle.
Right now, I have a watch sized system based on ATmega328PA, which drives 6 multiplexed blocks of 2x4 LEDs through MOSFETs on high and low side., powered from a Li-Ion battery. It is meant to show date and time, and to run simple programs such as snake, but the firmware is mostly unfinished.
The power supply starts with a USB port, which feeds power to a battery charging chip and directly to the 5V booster. The battery is also connected to the booster, behind a MOSFET which cuts it off while USB is plugged in. The booster then directly feeds Vcc.
The software is based on a state machine and lookup tables, this seems to be pretty good way to make interactive menus.
I am also going to design and 3D print a case at some point, although the priority now is to get everything soldered and programmed.