I always wanted to build my own binary clock. Well, at least since I've got interested in amateur electronics as a kid in the 1990's. Of course back then designing such a device was way out of my reach, due to lack of necessary skills, tools and parts. Even recreating someone's else design seemed to be too difficult, so I finally gave up.
Years have passed. World had changed. Then expensive and hard to get parts become obsolete and dirt-cheap. So, in 2017 I recalled my plan, that I abandoned years ago. I decided to give it a go.
The was to do it 90's style. No modern, powerful microcontrollers. No Internet connection. No NTP time synchronization. Just a plain, simple clock. For a little bit of retro styled design, I decided to use an AT89C51 MCU, interfaced with DS1307 RTC chip.
Time is set manually and then displayed on the LED matrix. There is also piezo buzzer, generating distinct "ticking" sound.