In September 2020, the internet witnessed one of the most absurd yet technically fascinating milestones in gaming history: a fully functional, interactive version of the 1993 classic Doom running inside the shell of a digital pregnancy test. The footage, which circulated widely on social media, featured the iconic pixelated corridors of Mars' moons rendered on a tiny, glowing monochrome screen.

However, behind the viral headlines lies a complex story of hardware "necromancy" and creative engineering. To understand how a device designed to detect human chorionic gonadotropin (hCG) hormones ended up slaying demons, one must look past the plastic shell and into the reality of modern microelectronics.

The Reality of Digital Pregnancy Test Hardware

To address the most common question: No, a standard digital pregnancy test purchased from a local drugstore cannot run Doom out of the box. To understand why, we must examine what actually happens inside these single-use devices.

The Myth of the "Smart" Tester

A common misconception is that digital pregnancy tests are complex computers. In reality, they are remarkably simple and optimized for a single, cost-effective task. A standard digital tester, such as those sold by Equate or Clearblue, consists of three main components:

  1. The Lateral Flow Strip: This is the same paper strip found in "analog" tests. It uses chemical reactions to indicate the presence of hormones.
  2. An Optical Sensor: A set of LEDs and photo-detectors that "read" the lines on the paper strip.
  3. A Simple ASIC (Application-Specific Integrated Circuit): A low-power, non-reprogrammable chip designed to interpret the sensor data and trigger the display.

These original chips have virtually no RAM, no video buffer, and no way to accept external code. Their displays are "segmented" LCDs—similar to those on a cheap digital watch—where only specific icons (like a clock or the words "PREGNANT") can be turned on or off. They are physically incapable of rendering a single pixel, let alone an 18MB first-person shooter.

The 2020 Breakthrough: How It Was Actually Done

The project that captivated the tech world was the work of a hardware enthusiast and programmer known as Foone. It was not a "hack" in the traditional sense of software exploitation; it was a complete internal reconstruction.

Replacing the Brains and the Eyes

To make the pregnancy test "play" Doom, the original internals had to be discarded. The shell remained, but the soul was replaced.

  • The Screen: Foone replaced the original segmented LCD with a 128x32 pixel monochrome OLED display. This allowed for the rendering of complex graphics and text that the original hardware could never achieve.
  • The Processor: The original ASIC was replaced with a more powerful microcontroller. In the finalized version of the project, an Adafruit Trinket M0 or similar small-form-factor board provided the necessary processing power to handle the game's logic.
  • The Input: Since a pregnancy test has no buttons, the device was connected to a wireless mini-keyboard, allowing the player to navigate the game's levels using traditional controls.

The Evolution from Video to Gameplay

The project actually occurred in two distinct phases. Initially, the developer shared a video of the Doom intro playing on the modified test. This led to skepticism and claims that it was merely a video playback. In response, within 24 hours, the project was upgraded to an interactive state. By piping the video output from a computer or using a more capable microcontroller to handle a trimmed-down version of the engine, the "Pregnancy Test Doom" became a legitimate, playable reality.

The Software Challenge: Dithering and Rendering

One of the most impressive technical aspects of this project was the graphical translation. Doom was originally designed for 256-color VGA displays. Porting that visual experience to a tiny, two-color (black and white) OLED screen required a technique called dithering.

Visual Fidelity on a Micro Scale

Dithering uses patterns of dots to simulate shades of gray. Because the 128x32 OLED cannot display gray pixels, it must "trick" the human eye. If a wall in Doom is supposed to be dark gray, the software places a checkerboard pattern of black and white pixels.

This required a custom rendering pipeline. The game's engine had to be adapted to output a 1-bit signal that remained readable at such a low resolution. Even at this scale, the "Doomguy" status bar, the weapon sprites, and the demonic enemies remained recognizable, a testament to the enduring strength of the game's original art direction.

Why Doom? The "Will It Run Doom?" Culture

The pregnancy test port is the crowning achievement of a long-standing internet subculture. The "Will it run Doom?" challenge is effectively the hardware hacker's version of a "Hello World" program. If you can get Doom to run on a device, you have proven your mastery over its hardware.

The Legacy of John Carmack’s Code

The reason Doom is ported to everything from printers to treadmills lies in its source code. When id Software released the code in 1997, it revealed an incredibly clean, modular architecture written in C.

  • Portability: The engine was designed to be portable across different operating systems of the 90s. This modularity means that as long as a hacker can write a "wrapper" for a new device's screen and input, the core game logic remains the same.
  • The WAD System: Doom separates its engine from its data (the .WAD files). This allows developers to swap out high-resolution assets for simplified ones that fit on low-memory devices.
  • Efficiency: The use of Binary Space Partitioning (BSP) trees allowed Doom to run on relatively weak 486 processors. This efficiency is what allows modern microcontrollers, which are often more powerful than 1993-era PCs, to handle the game with ease.

The "Ship of Theseus" Philosophical Debate

The pregnancy test project sparked a lively debate among engineers and enthusiasts regarding the definition of a "port." If the screen, the processor, and the memory of a device are all replaced, can we still say that the device is running the game?

Hardware vs. Form Factor

On one side of the argument, critics claim that this is merely "stuffing a computer into a plastic box." Since the original electronics were incapable, the achievement is more about miniaturization than hacking.

On the other side, enthusiasts argue that the "identity" of a consumer device is often tied to its form factor and intended purpose. By repurposing a single-use medical diagnostic tool—a symbol of high-stakes biological news—into a vehicle for 90s ultra-violence, the project creates a jarring and humorous juxtaposition that is the essence of the "Will it run Doom?" meme.

Beyond the Pregnancy Test: Other Strange Ports

While the pregnancy test remains a viral favorite, it is part of a larger pantheon of strange Doom hosts. These projects highlight the ingenuity of the global developer community:

  • The McDonald’s Cash Register: In 2019, a teenager managed to run the game on a discarded POS terminal from a fast-food restaurant.
  • Digital Cameras: Several Kodak and Sony cameras from the late 90s, which ran early versions of the Digita OS, have been successfully used to slay imps.
  • Calculators: The TI-83 and TI-84 graphing calculators are classic hosts, though they often require "potato" power or significant battery arrays to run at full speed.
  • The MacBook Pro Touch Bar: Hackers managed to squash the game into the ultra-wide, ultra-thin resolution of Apple's secondary display strip.

Conclusion on the Technical Feat

The pregnancy test Doom project is a masterclass in hardware "remixing." It serves as a reminder that the boundaries of what technology can do are often limited only by the imagination of the person holding the soldering iron. While you cannot simply walk into a pharmacy, buy a test, and start playing, the fact that such a small form factor can host a legendary 3D engine is a testament to the incredible power of modern microcontrollers and the timelessness of Doom's code.

It transforms a discarded piece of "e-waste"—a single-use plastic device that would otherwise end up in a landfill—into a conversation piece about engineering, nostalgia, and the persistent human urge to make things do what they weren't supposed to do.

Summary of the Technical Reality

  • Stock Hardware: Incapable of running the game due to segmented LCDs and non-programmable chips.
  • The Modification: Involved replacing the internal CPU with a microcontroller and the LCD with a monochrome OLED.
  • The Resolution: 128x32 pixels using 1-bit dithering.
  • Input: Achieved via an external wireless keyboard connected to the new internal processor.

FAQ

Can I play Doom on a pregnancy test I bought today?

No. Standard digital pregnancy tests use extremely limited hardware that cannot be reprogrammed or used to display game graphics. You would need to replace the internal components with a microcontroller and an OLED screen.

How much did the modifications cost?

The components used in the viral project (a small microcontroller and an OLED display) typically cost between $15 and $30. The most difficult part is the labor and soldering required to fit the components into the small plastic shell.

Was the game actually running on the test or just a video?

The initial viral post showed a video, but the developer quickly updated the project to be fully interactive. The "interactive" version involved the microcontroller receiving inputs from a keyboard and rendering the game frames to the OLED screen.

Is the pregnancy test still functional for testing pregnancy?

No. Once the device is opened and the original sensor and chemical strip are removed to make room for the new electronics, it can no longer detect hormones.

Why is Doom the only game people port to these devices?

Doom is chosen because its source code is open-source, written in highly portable C, and the engine is incredibly efficient. It has become a standardized benchmark for hardware hackers.