Maker and vintage computing enthusiast Trevor Flowers has put together an ultra-compact clone of the Tandy-Radio Shack TRS-80 microcomputer — powered by an Adafruit QT Py board running CircuitPython.
Released in 1977 by Tandy through its Radio Shack store fronts, the original TRS-80 — later rebadged to the Model I — kicked off a family of microcomputing devices which would run the gamut from all-in-one systems with floppy drives and CRT displays to the popular TRS-80 Model 100 portable. The TRS-80 Model II, released in 1980, came with the aforementioned display, up to two 180kB floppy drives, up to 48kB of RAM, and a Zilog Z80A processor running at 2MHz.
Flowers' miniature recreation, though, has very different specifications. Inside the 3D-printed chassis lies an Adafruit QT Py S3 microcontroller development board, which despite its diminutive size boasts an Espressif ESP32-S3 chip with two Tensilica Xtensa LX7 cores running at up to 240MHz, 512kB of static RAM (SRAM), 2MB of pseudo-static RAM (PSRAM), and 4MB of flash storage — all upgrades on the TRS-80 by multiple orders of magnitude.
"This [miniature] is driven by this QT Py running CircuitPython or Arduino," Flowers explains. "So, there's not an accurate TRSDOS or VDOS emulator for it. On the other hand it has Wi-Fi, BLE [Bluetooth Low Energy], and more memory and pixels than the original."
The project builds on Flowers early display-only TRS-80 miniature model, which lacked electronics and instead used swappable cards to simulate a static display. "As shipped," Flowers explained of the original, which was created to a 1:6 scale, "it will show a short BASIC program." The new variant, though, can display animations — or even double as a functional Internet of Things (IoT) connected display system in a retro-themed chassis.