In September 2020, the internet witnessed one of the most absurd yet technically fascinating crossovers in gaming history: a fully functional version of the 1993 first-person shooter Doom running on a digital pregnancy test. The viral videos, shared by programmer and hardware enthusiast Foone Turing, sparked a wave of disbelief, technical debates, and a resurgence of the "Will it run Doom?" meme.

However, beneath the low-resolution, monochrome pixels of the "Slayer" fighting demons on a device meant for biochemical testing, lies a complex story of hardware reverse-engineering, social commentary on e-waste, and a fundamental misunderstanding of what a digital pregnancy test actually is.

The Short Answer: Did It Really Run on the Original Hardware?

To address the most common question immediately: No, Doom was not running on the original processor or display found inside a standard digital pregnancy test. The internal electronics of a store-bought digital pregnancy test are far too limited to handle the logic, rendering, or memory requirements of a 3D game engine, even one as efficient as Doom.

Instead, this project was a brilliant "shell swap." Foone Turing used the plastic housing of an Equate-brand digital pregnancy test but completely gutted its internals, replacing the original one-time-programmable chip and the fixed-icon LCD with a modern microcontroller and a high-resolution (by comparison) OLED display.

The Legend of "Will It Run Doom?"

Before diving into the hardware specifics, it is essential to understand why this project happened at all. In the world of hardware hacking and retro-computing, "Will it run Doom?" is more than a question—it is a rite of passage.

Ever since id Software released the source code for Doom in 1997, developers have treated the game as the ultimate "Hello World" for hardware. Because the engine was written in highly portable C and designed to run on the relatively modest 386 processors of the early 90s, it has been successfully ported to an incredible array of devices:

  • Printers: Specifically those with LCD screens and enough onboard memory to cache print jobs.
  • ATMs: Which often run on stripped-down versions of Windows XP or OS/2.
  • Smart Refrigerators: Utilizing their Android-based interfaces.
  • Graphing Calculators: Such as the TI-83, though these versions are often heavily modified clones.
  • Vibrators and Smart Toothbrushes: Any device with a small CPU and a display is a target.

The pregnancy test was the "Final Frontier" of this challenge because of the sheer perceived simplicity of the device.

Anatomy of a Digital Pregnancy Test: A High-Tech Illusion

To appreciate why Turing had to replace the internals, we must first look at what is actually inside a digital pregnancy test. Many consumers assume that because the device has a screen and costs $10–$20, it must be doing some complex digital analysis.

The reality is much simpler. Inside a digital pregnancy test like Clearblue or Equate, there is a standard paper strip—the same kind used in $1 "analog" tests. The digital components consist of:

  1. Three LEDs and Photodiodes: These act as optical sensors to "read" the lines on the paper strip.
  2. A Basic Microcontroller: Usually an 8-bit chip, often an OTP (One-Time Programmable) variant. This chip is programmed at the factory to do one thing: interpret the light reflected from the paper strip and determine if one line or two lines are present.
  3. A Custom LCD: These are not pixel-based screens. They are "segmented" LCDs, similar to a digital watch, designed only to display specific icons like a "plus" sign, a "minus" sign, or the words "PREGNANT" and "NOT PREGNANT."

From a technical standpoint, the original hardware is a "dead end." The CPU cannot be reflashed with new software, and the screen is physically incapable of drawing a single pixel of a demon or a shotgun.

The Re-Engineering Process: How Foone Turing Did It

Turing’s project evolved in two distinct stages. Understanding these stages is crucial for anyone looking to replicate such a feat or understand the technical nuances of hardware hacking.

Stage 1: The Video Playback Trick

Initially, Turing posted a video of Doom (and other clips, like the music video for "Never Gonna Give You Up") playing on the pregnancy test. At this point, it wasn't a game being "run" on the device; it was essentially a tiny video monitor.

The segmented LCD was replaced with a 128x32 pixel monochrome OLED display. This screen fits perfectly into the window of the pregnancy test shell. In this stage, the display was being driven by an external PC, acting as a secondary monitor for a video file. While impressive, it wasn't yet "playing" Doom.

Stage 2: The Interactive Game

Following the viral success of the playback video, Turing took it a step further. They integrated a small microcontroller (likely from the Arduino or ESP32 family, though specific iterations varied during the project) into the setup.

The final "interactive" version involved:

  • The Processor: A microcontroller powerful enough to handle a port of the Doom engine.
  • The Display: The 128x32 I2C OLED mentioned above.
  • The Input: Since a pregnancy test has no buttons, Turing connected a wireless Bluetooth keyboard to the microcontroller.
  • The Power: An external power source, as the coin-cell battery in a standard test wouldn't last long under the load of a modern microcontroller and OLED.

In the final video, you can see Turing moving the character, firing the weapon, and navigating the corridors of E1M1. It is a genuine, interactive port of the game, living inside the "husk" of a medical diagnostic tool.

Technical Challenges: Rendering 3D on a 128x32 Canvas

Playing Doom on a 128x32 display is a unique experience that highlights the brilliance of the game’s original design. Doom uses a technique called Binary Space Partitioning (BSP) to render its 3D environments. While it was revolutionary in 1993, on a 128x32 monochrome screen, it becomes a chaotic dance of pixels.

The Resolution Problem

A standard VGA resolution for Doom was 320x200. Shrinking this to 128x32 represents a massive loss of data. Specifically:

  • Verticality: With only 32 pixels of vertical height, the status bar (which shows health, ammo, and the Doomguy’s face) has to be removed entirely to make the game world visible.
  • Visibility: Enemies like Imps or Cacodemons become mere clusters of three or four moving pixels when they are across a room.

The Monochrome Challenge

The OLED display used was monochrome (white on black). Doom relies heavily on lighting and color contrast (red for fireballs, green for toxic slime). To make the game playable, Turing had to "crunch" the game's palette. In the hardware hacking community, this is often done using dithered thresholds, where different shades of gray are represented by varying patterns of black and white dots. Turing noted that increasing the in-game gamma was necessary to see anything at all in the dark corridors of the Martian moon bases.

The Philosophy of "E-Waste" and the Digital "Scam"

Beyond the technical wizardry, Turing used the project to highlight a significant issue in the consumer electronics industry: the proliferation of unnecessary digital waste.

The project demonstrated that a digital pregnancy test is essentially a $1 test strip wrapped in $10 worth of electronics that are immediately thrown into a landfill after a single use. The "digital" aspect adds zero accuracy to the chemical test; it simply provides a more user-friendly way to read the result.

By showing that these devices can house a screen and a processor capable of (with slight modifications) running complex software, Turing pointed out the absurdity of our disposable tech culture. Every "digital" test thrown away contains a battery, a circuit board, and a liquid crystal display—materials that are environmentally taxing to produce and difficult to recycle.

The Legacy of the Pregnancy Test Port

The "Pregnancy Test Doom" project remains a landmark in internet culture for several reasons. First, it pushed the "Will it run Doom?" challenge to its logical extreme. If you can fit the game into a device designed to be urinated on and discarded, where else can it go?

Second, it served as a masterclass in transparency for hardware hacking. Throughout the process, Turing was open about what was original and what was replaced. They didn't claim to have "hacked" the original 8-bit chip, which would have been an impossible task given its architecture. Instead, they showcased the art of "retrofitting"—giving new, absurd life to an old shell.

Finally, it inspired a new generation of "makers." The project showed that with a basic understanding of microcontrollers, I2C displays, and C programming, one could transform almost any household object into a gaming console.

Why Doom is the Perfect "Hello World" for Porting

One might wonder why hackers always choose Doom instead of Super Mario Bros or Pac-Man. The answer lies in the architecture of the engine itself.

  1. Fixed-Point Math: John Carmack and the team at id Software avoided using floating-point math because many CPUs in the early 90s didn't have a Floating Point Unit (FPU). This makes Doom extremely compatible with low-power microcontrollers that also lack FPUs.
  2. Modular Renderer: The way Doom draws its columns and spans (floors/ceilings) is highly efficient. It doesn't require a GPU; it is a software-rendered engine.
  3. WAD Files: The game logic is separate from the assets (the .WAD files). This allows hackers to easily swap out textures or downsample graphics to fit the memory constraints of weird hardware.

Conclusion: The intersection of Meme and Machine

The story of running Doom on a pregnancy test is a testament to human curiosity and the sheer flexibility of 90s software engineering. While the "digital" part of the pregnancy test was ultimately a plastic shell for a more powerful microcontroller, the project achieved its goal: it captured the world's imagination and reminded us that with enough soldering and code, anything can be a game console.

It stands as a reminder that "It runs Doom" is not just a joke—it’s a celebration of the portability of code and a critique of the disposable nature of modern technology.

Summary

In 2020, programmer Foone Turing viralized a project where Doom was played on a pregnancy test. The core of the project involved replacing the original, limited electronics of an Equate digital pregnancy test with a more powerful microcontroller and a 128x32 OLED display. While the original hardware was incapable of running the game, the project successfully utilized the device's shell to create a fully interactive, albeit tiny, version of the legendary shooter. The experiment also served as a critique of the environmental waste generated by single-use digital consumer products.

FAQ

Is there a version of Doom that runs on an unmodified pregnancy test?

No. The original hardware in a digital pregnancy test uses a "one-time programmable" (OTP) chip and a segmented LCD. These components cannot be reprogrammed to run external software or display pixel-based graphics.

Who created the Doom pregnancy test hack?

The project was created by Foone Turing, a California-based programmer and hardware reverse-engineer known for working with vintage and unusual technology.

What kind of screen was used in the modification?

Foone Turing used a 128x32 pixel monochrome OLED display. This was small enough to fit inside the original plastic window of the pregnancy test housing.

How did the player control the game?

Since a pregnancy test has no buttons, the modified device was connected to an external wireless Bluetooth keyboard, which sent inputs to the microcontroller running the game.

Does a digital pregnancy test work better than a regular one?

Internally, they use the same chemical test strip. The digital component simply uses optical sensors to read the lines for you, reducing the chance of human error in interpretation, but the underlying science is identical.