DUO BINARY is a very, very small computer system in every possible sense. It runs on an ATtiny84, which has even got “tiny” in its name. The user interface is a single button for data entry and a single LED for feedback, making this binary keyboard look frivolously over-complicated. It uses a devilish chimera of Morse code and a truncated ASCII to enter data, and the LED blinks the same back at you.
We’re guessing that [Jack Eisenmann] is the only person in the world who can control this thing, and you can watch him doing so in the video embedded below.
But just because this system is minimalistic doesn’t mean that it isn’t powerful. It’s got 128 K of SRAM and 2 MB (!) of flash onboard that the “operating system” can make use of. (We can’t imagine entering 2 MB of data in Morse code, so we presume that’s why the flash is socketed.) With so much flash memory, it’s no surprise that [Jack] implemented a file system.