Pineapple ONE is a functioning processor, that is based on an open-source architecture RISC-V. This architecture is becoming very popular these days, and it is well, open-source, so we chose to build a cpu only out of discrete, off-the-shelf components. Our goal is to prove that designing a “Modern” CPU isn’t that hard, so we have released our schematics and made it open source as well. Filip Szkandera spent two years designing and building a 32bit CPU utilising the RISC-V architecture.

Source: Pineapple ONE

A CPU hand-built by a 19-year-old that runs at 500 kHz. This is really cool!