How One Engineer Hand‑Built a DIY CPU from Scratch – Specs, Challenges, and Lessons

In 2024, a B‑station creator known as “焊武帝” (the soldering emperor) unveiled a completely hand‑crafted CPU called “初芯”, built from discrete components such as diodes, transistors and resistors.

The CPU contains over 20,000 components and more than 100,000 solder joints, costing roughly ¥2,000 in parts (under ¥1,000 for basic components). Its specifications include a 13 kHz base frequency (up to 33 kHz over‑clock), 64 kB ROM with hot‑update support, 256 B system memory, 64 kB application memory, 78‑bit I/O (48 bits with bit‑operations), 103 instructions and a power consumption of about 10 W.

Performance is comparable to early 1970s CPUs, capable of driving a simple display, rendering text and images, and even running tiny games like Snake.

The creator, Lin Nai‑wei, spent two years designing the logic, PCB, and soldering the board, then another year and a half debugging and extending the instruction set to over 100 commands, adding stack, more I/O, and memory management.

He also introduced a unique dual‑channel memory scheme that physically separates global and local variables onto different memory controllers, allowing the 64 kB application memory to be accessed with a single instruction.

Despite the massive effort, the project serves as a proof‑of‑concept for a future commercial CPU, demonstrating the feasibility of low‑cost, fully self‑designed hardware.