Retrocomputing enthusiasts will be delighted to learn that a new ZX Spectrum replica is on the market: the ESP32 Rainbow. The single board computer swaps the Zilog Z80 for an ESP32-S3 microcontroller chip running an emulator, bringing the classic 80s computer back to life with a modern twist.
It features a built-in color display, a microSD card slot for storage, a built-in touch keyboard in the ZX Spectrum style, and a USB Type-C port for power and data. The keyboard was recreated using full-color UV printing and is the most true-to-life component of the ESP32-S3-based ZX Spectrum single board computer. The touch keys won’t likely offer the best typing experience but that is reminiscent of the original ZX Spectrum. A lovely cherry on top is that the onboard USB-C port supports HID and the device can be used as a keyboard on another computer.
The ZX Spectrum is one of the best-selling keyboard computers ever and is a predecessor to modern products in the form factor such as the Raspberry Pi 400. However, nolstagia isn’t the ESP32 Rainbow’s only appeal. It is also designed to be hackable with an expansion port that breaks out the display, SD card, speaker, and four GPIO pins.
The ZX Spectrum Next is another ZX Spectrum emulator you may be interested in. We also covered the Retro-uC microcontroller supporting retro CPU cores including the ZX Spectrum’s Z80. Finally, the Espectrum is another ESP32-based ZX Spectrum replica running open-source firmware of the same name and also working on ESP32 boards with VGA such as the Olimex ESP32-SBC-FabGL.
ESP32 Rainbow specifications:
- Module – ESP32-S3-WROOM module with
- SoC – ESP32-S3 dual-core XTensa LX7 MCU clocked at 240 MHz; 512KB SRAM; 8MB PSRAM; 8MB flash
- Wireless- WiFi 4 and Bluetooth 5.x
- Storage – microSD slot for storage
- Display – 320 x 280 color TFT display
- Audio
- Built-in 2 W, 8-ohm speaker
- Simple buzzer and AY-3-8912 (three-voice sound generator) emulation
- Headphone jack
- USB – USB Type-C power and data
- Keyboard – 40 key full-color ZX Spectrum-style touch keyboard
- Expansion
- 2x QWIIC connectors
- Expansion port that breaks out the display, SD card, speaker, and four GPIO pins
- Misc – Reset and BOOT buttons
- Power Supply- Picoblade-compatible battery connector and charging circuit
- Emulates both 48K and 128K ZX Spectrum
The ESP32 Rainbow is an open hardware project released under the GNU General Public License (GPL), with KiCad project files, a bill of materials, and open-source emulator firmware available on GitHub. Documentation and user support will be available in the form of assembly, setup, and usage guides, and a dedicated Discord server for the project.
The ESP32 Rainbow crowdfunding campaign is scheduled to end by December 19 and has amassed up to 80% of its funding goal. You can order the keyboard computer and back the project on Crowd Supply for $99, with $8 for US shipping and $18 for the rest of the world. Deliveries are scheduled to start on April 2025.
Tomisin is a writer specializing in hardware product reviews, comparisons, and explainers. He is very passionate about small form factor and single-board computers.
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