July 14, 2026
Pocket calculator, huge feelings
Casio FX870P Emulator
This tiny 1986 pocket computer just sent nostalgia fans into a full-on meltdown
TLDR: A developer put a 1986 Casio pocket computer in your browser, turning a niche retro gadget into something anyone can try. Commenters immediately made it about nostalgia, desk-shrine bragging rights, and demands for even stranger old devices to be resurrected next.
A humble browser remake of the 1986 Casio FX-870P should have been a quiet retro-computing story. Instead, the comments instantly turned into a vintage gadget reunion. The project itself is delightfully nerdy: a working version of an old programmable calculator-computer you can run in your browser, complete with its little screen, keyboard, file storage tricks, and even a turbo mode. In plain English, someone lovingly brought a weird old pocket machine back to life online so modern people can poke at it without hunting eBay for aging hardware.
But the real spectacle was the community mood: pure nostalgic chaos. One commenter didn’t just say “cool,” they basically rolled out a mini museum, bragging that they keep a Casio FX-850P, a ZX Spectrum, and an Atari Portfolio on their desk as “witnesses” to a glorious past. That one comment set the tone: less product launch, more emotional support group for people who refuse to let the 1980s die. The hottest take wasn’t even criticism — it was a flex. Meanwhile, another commenter immediately widened the battlefield, wondering if someone will now emulate old electronic dictionaries too, which is exactly the kind of wonderfully specific internet rabbit hole that makes retro tech fans impossible to stop.
So yes, the emulator is impressive. But the comments made it feel like a class reunion where everyone showed up carrying obsolete gadgets and demanding the next revival already.
Key Points
- •The project is a browser-based emulator of the 1986 Casio FX-870P/VX-4 pocket computer, implemented in TypeScript and Vue 3 as a web port of a Delphi reference emulator.
- •It emulates the original hardware in detail, including the Hitachi HD61700 CPU at 921 kHz, memory map, HD44352A01 LCD controller, 83-key keyboard, UART serial, and MD-120 floppy storage.
- •The emulator includes user-facing features such as responsive UI scaling, PC keyboard mapping, a built-in BASIC program library, floppy support, serial LOAD/SAVE, fullscreen mode, and firmware switching between Japanese and English ROM modes.
- •Advanced tooling includes a CPU debugger, live detokenized BASIC listings, an in-place BASIC editor with RAM writes, a communications diagnostics panel, and character editing via DEFCHR$.
- •The project requires Node.js 22 LTS and external ROM files, provides npm-based development and production workflows, and serves the app from the /fx870p-emulator/ base path.