The hardware for the system consists of a TI-84 graphing calculator, a few bits and bobs in the way of components, and an Arduino Pro Mini powered from the USB port on the calculator. The Arduino ...

You can leave the TI graphing calculator at home thanks to this web-based TI-83 and TI-84 emulator. As with pretty much all emulators, this depends on a ROM image from the actual hardware to work.