Maker Kati (missmolerat) has designed Clotty, a palm-sized RP2040 board cut in the shape of a uterus. It's meant to be an offline, privacy-first period tracker that plays like a Tamagotchi, and it passed the hacker world's oldest test early: it runs DOOM. The two ovaries are capacitive touchpads, the screen sits in the middle, and the USB-C port is exactly where you'd guess. Kati says the shape was deliberate, a way to push back on the stigma around periods, and a uterus also turns out to be surprisingly game-controller-shaped.
Video: DOOM gameplay on Clotty, by Kati (missmolerat).
What's on the board
At the heart of Clotty is an RP2040 with 16 MiB of W25Q128 QSPI flash and a 1.3-inch 240×240 ST7789 IPS display over SPI. An RV-8263-C7 RTC keeps track of dates, and a CAP1203 controller reads the touch-sensitive ovaries over I2C. The sensors are an MCP9808 for temperature, a TEMT6000 for ambient light, a LIS3DH accelerometer and a DRV5032 Hall sensor. They're there for planned quests like warming Clotty up with a "hot water bottle" or putting her somewhere dark for a nap. The board also has an RGB LED, three buttons, LiPo charging and a buck-boost power stage.
The clever bit: making DOOM playable
The DOOM build is based on kilograham's rp2040-doom. Kati replaced its scanvideo output with a simple blocking SPI driver and scaled the 320×200 frame horizontally to 240×200 to fit the display. The ovaries move forward and "use" things, and the buttons turn and fire. Her first attempt pushed each roughly 96 kB frame out on core 1, which starved the renderer, so gameplay stalled as soon as a level loaded. The fix was to leave core 1 entirely to rendering and do the SPI transfer on core 0 once a full frame is ready. That's what took it from "technically displays DOOM" to "kinda playable". The Ultimate DOOM WAD lives in its own area of the flash, and the firmware itself is a UF2 of about half a megabyte.
Where it stands
Clotty is a working prototype. Basic bring-up passes on every part, from the display and touch ovaries to the sensors, RTC and charger, but the period-tracking and Tamagotchi firmware is still being written, and Kati lists known layout issues in the repo. The KiCad files, Gerbers and BOM are on GitHub under CERN-OHL-S-2.0, and her DOOM changes are in a separate fork. Her full write-up covers the design story in detail.
Image credit: Kati (missmolerat), CC BY-SA 4.0, cropped and resized.
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