### KiDoom: When Your Circuit Board Itself Becomes the Screen

The age-old question in tech circles, “But can it run DOOM?”, has become a benchmark for creativity and technical prowess. We’ve seen the iconic 1993 shooter run on everything from pregnancy tests to calculators. But a recent project, unveiled in a “Show HN” post, has taken this challenge to a new, mind-bending level. Meet KiDoom, a project where DOOM isn’t just running on a device built on a PCB—it’s running on the PCB traces themselves.

At first glance, the concept is difficult to grasp. How can copper traces, the simple electrical pathways on a circuit board, run a video game? The genius of KiDoom, created by maker and engineer Jeroen Domburg, lies in redefining what a “screen” can be. This isn’t about processing power hidden in the copper; it’s about using the PCB design itself as the display medium.

#### How It Works: PCB as a Display

The KiDoom project is, at its core, a custom-designed circuit board that functions as an extremely low-resolution display. The “screen” is an 8×32 matrix of 256 red LEDs. The magic is in how these LEDs are wired. Instead of a standard, grid-like layout hidden under a silkscreen, the copper traces that connect the LEDs are meticulously routed in KiCad (an open-source electronics design suite) to form intricate patterns. These patterns aren’t just functional; they are the game’s level maps.

When the game is running, the LEDs light up to represent the player’s view within the game world—walls, doors, and corridors. As you move through the digital space, the corresponding LEDs on the physical PCB light up. The effect is mesmerizing: you are literally seeing the game’s first-person perspective rendered across the same copper pathways that represent the game’s entire map. The PCB is simultaneously the circuit, the display, and a piece of art.

#### The Brains Behind the Board

Of course, the traces themselves aren’t performing the calculations. The game logic is handled by a powerful yet tiny Raspberry Pi RP2040 microcontroller. This chip runs a port of the original DOOM engine. It processes player input from a small joystick and buttons mounted on the board, calculates the game state, and determines which of the 256 “pixels” (the LEDs) should be illuminated to represent the player’s current view.

The rendering is a feat of simplification. The 3D world of DOOM is downscaled and translated into a simple, 1-bit color depth (on or off) representation on the 8×32 LED grid. While it’s far from a high-definition experience, it’s unmistakably DOOM. You can navigate the levels, open doors, and experience the classic game in a way no one has before.

#### More Than a Game: A Feat of Engineering Art

KiDoom is the ultimate expression of “PCB art,” a growing movement where engineers and artists use the constraints of circuit board design as an artistic medium. The routing of traces becomes a form of illustration, and the placement of components contributes to a larger aesthetic. In this case, the art is not just static; it’s interactive and dynamic.

This project is a testament to the hacker spirit. It wasn’t created to be a practical way to play DOOM, but to push the boundaries of what’s possible and to merge software, hardware, and design in a novel way. It’s a physical artifact that is both the game console and the game cartridge, where the hardware is inextricably linked to the software it runs.

The reaction from the tech community on Hacker News and beyond was one of universal awe. It’s a project that makes you rethink the relationship between the physical and the digital. KiDoom doesn’t just ask if a device can run DOOM; it asks if the very fabric of the device can *become* DOOM. And the answer is a resounding, brilliantly-lit yes.