Creating a portable ZX Spectrum-compatible device involves shrinking the footprint without losing the "soul" of the machine. The original design used a rubber chiclet keyboard that was notoriously difficult to type on, but essential for the Spectrum’s aesthetic.
For those seeking more power, the combines an FPGA-based Spectrum Next board (a modern reimagining of the original hardware, not merely an emulator) with a Raspberry Pi Zero, an 8-inch 4:3 LCD screen, and stereo speakers inside a custom 284×151mm clamshell case. Meanwhile, Ben Heck's custom portable build demonstrates that a dedicated hardware approach—using a fabricated PCB with the original Z80 CPU and custom video controller—remains viable for purists. Even Soviet-era clones find new life in portable form: the Delta-S design, which used conventional chips instead of a ULA, has been reproduced in KiCAD, upgraded with 128K RAM and floppy drive support, and housed in a brutalist 3D-printed enclosure. If you are planning to build your own
For the Spectrum, this meant Sinclair could take dozens of discrete logic chips—responsible for video timing, memory addressing, keyboard scanning, and sound generation—and compress them into a single, custom slab of silicon. has been reproduced in KiCAD
If you are planning to build your own retro hardware, let me know: Will you use an or a real Z80 hardware chip ? What screen size are you targeting for the portable case? custom slab of silicon.
It handles the row and column address strobe signals (RAS and CAS) to multiplex memory addresses for the lower 16KB of RAM.
Start with the holy trinity of computing. You cannot build a microcomputer without: