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 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 — 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.