If you’re under the age of 35, you almost certainly used the Texas Instruments TI-83 graphing calculator in school. It’s been popular for decades now, and is even a requirement for many math classes. As you’d expect, upgraded versions have been released over the years. The newest — at least in France — is the TI-83 Premium CE, which offers a number of new features, including a color screen. As it turns out, you can also use it to run Adafruit’s CircuitPython through an adapter.
To compete with other modern calculators like the NumWorks graphing calculator, Texas Instruments wanted the new TI-83 Premium CE to run Python. Unfortunately, because of some quirky limitations with the calculator’s eZ80 processor, they weren’t able to get a Python interpreter running on the actual calculator. The solution they came up with was to sell the TI-Python adapter, which is an external device that plugs into the calculator and runs the Python interpreter. The calculator simply acts as an interface for that device.
Interestingly, the TI-Python adapter has a Microchip ATSAMD21E18 chip and runs Adafruit’s CircuitPython instead of the more common MicroPython. That means you can use an CircuitPython-compatible development board from Adafruit to create your own TI-Python adapter. You will have to use a tool like Zadig to change the device’s VID/PID to match what the TI-83 Premium CE is expecting to see. But after doing so, you’ll be able to use non-TI hardware with your calculator. There is already modded firmware to do that, and even a Game Boy emulator you can use to play games.