Clotty is a palm-sized, uterus-shaped PCB period tracker built by [kati] around an RP2040, a color LCD display, and touchpad ovaries. It does not upload your data to a remote server. It does not harvest, sell, or disclose it. That single property, which should be baseline, places it ahead of most commercial period tracking apps on the market.
The hardware is functional. Software essentials are in place and active development continues on the GitHub repository at github.com/bitshiftcrazy/clotty. The design is deliberately unsubtle, built to announce its purpose on sight, and layers a Tamagotchi-style interaction model on top of core cycle tracking. It also runs DOOM via [kati]'s fork of RP2040-DOOM.
The full writeup is worth reading for the design philosophy behind the data privacy decisions and the hardware choices that make those decisions possible. [kati] previously built the Slightly Sentient D20, covered by Hackaday in May 2026, which shows a consistent pattern: functional hardware with deliberate personality baked into the form factor, not bolted on after.
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