The Cheap Yellow Display (CYD) is a board carrying a slightly older ESP32 variant, a display with a resistive touchscreen, an SD card, and not much else. It’s often used for straightforward microcontroller applications that need a user interface, but that’s not the limit of its possibilities. [Alun Morris] has a CYD on which you can brows an entire offline Wikipedia.

The trick is to take the offline Wikipedia builds from the Kiwix project, and process them further into a custom format suited for a browser firmware on the ESP32. A modern SD card can hold so much data that a full Wikipedia is well within its abilities even with images included.

We like this idea, because it takes the knowledge away from the center of the network to its edge. We expect to see it gaining a following among enthusiasts for offline living, because all that knowledge without a network can only be useful. If you recognize [Alun]’s work, it might be because of his ESP32 web browser.