ESP32 runs System 3

A $15-to-$30 Cheap Yellow Display can now boot a Macintosh Plus emulator and show live weather inside Apple’s 1980s System 3 software shell. (hackaday.com) The build runs on an Espressif ESP32-S3 board with a 240 by 320 ILI9341 screen and XPT2046 touch controller, sold as the Cheap Yellow Display or CYD2USB. The project page says the touch panel acts as the Mac mouse, and the enclosure is a 3D-printed mini computer case. (github.com) A software emulator is a program that imitates one computer inside another, the way a game console emulator imitates old hardware on a laptop. In this case, likeablob’s Cydintosh uses the umac Macintosh Plus emulator and the Musashi Motorola 68000 processor core to recreate a 1986-era Mac on the ESP32 board. (github.com) The weather screen is not a skin pasted over modern graphics. Hackaday reported on April 13 that the forecast app is a custom 68k Macintosh program, compiled with Retro68, while the ESP32-S3 handles the Wi-Fi link underneath. (hackaday.com) That split lets the old Mac software talk to modern hardware through a fixed memory address, 0xF00000, which Hackaday said is used to pass commands and read data back. The result is a small dashboard that looks like System 3.3 but can still pull current data over a home network. (hackaday.com) The project arrives as the Cheap Yellow Display has become a common entry-level board for hobbyists because it combines an ESP32, touchscreen, and case-friendly form factor in one module. Hackaday framed this build as a twist on the familiar ESP32 weather display by turning the dashboard into a full Macintosh environment instead of a single-purpose interface. (hackaday.com) The repository lists a short bill of materials: one CYD2USB board and four M2 by 3 self-tapping screws for the enclosure. It also requires a Macintosh Plus ROM v3 file at 128 kilobytes, a System 3.2 boot disk image at 400 kilobytes, and an 800-kilobyte hard disk image that includes prebuilt Mac apps named CydCtl, Weather, and WiFi. (github.com) The code and model files were published on GitHub, and the Hackaday.io project page says the project was created on April 11, 2026. Both pages say the software includes Home Assistant integration, so the tiny Mac can act as a smart-home display as well as a retro desktop. (hackaday.io) Hackaday tied the emulator back to evansm7’s Micro Mac work, which also powers the Raspberry Pi Pico-based PicoMac. On the ESP32 version, the old Finder and the live forecast end up sharing the same screen, which is the whole trick: a practical weather panel that behaves like a compact 1980s Macintosh. (hackaday.com)