Mitsuru Yamada's PERSEUS-9 Is a Dual-6502 Portable Designed with Retro-Chic Aesthetics

Building on earlier PERSEUS models and a bubble LED serial console, this dual-CPU aluminum portable is a wire-wrapped wonder.

Gareth Halfacree
21 days ago β€’ Retro Tech / HW101

Engineer and vintage processor enthusiast Mitsuru Yamada has put together a portable computer with a difference: the PERSEUS-9 boasts dual MOS 6502 eight-bit processors and a wide format LED matrix display.

"In 2021, I built my own floating-point interpreter system on my PERSEUS-8 computer," Yamada explains of the device's origins. "However, this system required a serial terminal for input/output, which was somewhat inconvenient to use for programming and calculation whenever I wanted. Therefore, I have developed the PERSEUS-9, a mobile stand-alone computer that can run this system independently."

The gorgeous PERSEUS-9 is a portable computer built around vintage technology. (πŸ“Ή: Mitsuru Yamada)

The machine is truly mobile, despite being built around a pair of processors launched back in 1975 and installed using exclusively through-hole technology on wire-wrap board. PERSEUS-9's die-cast aluminum case is built with portability in mind, and houses a 48-key keyboard and a 40-character seven-line display built using a matrix of glowing character LEDs. When in use, the gadget only requires a power supply connecting to built up ready for work β€” or can manage around an hour of operation from four rechargeable AA batteries.

"PERSEUS-9 […] is about 5cm [around 1.97"] thick," Yamada notes, "but has about the same dimensions in length and width as a current notebook PC. I was able to create a computer for myself that can be easily used for calculations in place of a calculator and for simple mathematical and physical programming calculations. Furthermore, I can easily experiment with direct access to the parallel interface by using pointer variables. Comparing the floating-point arithmetic errors of my interpreter with the results obtained by the current PC-based computation language system is endless interest to me."

This is far from Yamada's first device built around vintage microprocessors: Two years ago we looked at the PERSEUS-3, a precursor to today's PERSEUS-9, with its rack-mount design, front-panel switches, and Motorola MC6802 inside; the newer PERSEUS-7, built around the same MOS 6502 chips as the PERSEUS-9, enjoyed the benefit of an add-on for reverse Polish notation (RPN); and before that he put together a serial terminal with bubble LED display. The PERSEUS-9 builds on all these projects, Yamada explains.

Full details on the PERSEUS-9, including schematics, block diagram, and source code, are available on Yamada's Hackaday.io page.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire: freelance@halfacree.co.uk.
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