Here's something I'm definitely going to spend all week trying to set up and then using once to continue avoiding buying a Freewrite or whatever: Ruben Berenguel's PiWrite, a Goldbergesque system for using a Kindle as a writing device. You have a simple web-based text editor running on a server running on a Pi Zero W, and use the Kindle's "experimental" web browser to access it. Your keyboard is connected to the Pi.
I was inspired by SolarWriter by Michael Solomon. I had always wanted to use my Kindle for writing. SolarWriter solves that by setting up a local web server on your phone (iOS or Android), then you type with a Bluetooth keyboard paired with it. But you need to set up hotspot, keep your screen on… I didn't like those parts. So I wrote this.
It looks effective and workable, though I'm already stricken thinking about the cumulative latency of a Pi Zero, a webserver running on a Pi Zero, the Kindle browser app, and an e-ink display. I don't know—how much worse than a space cadet keyboard can it get?