2026 Retrocomputing Challenge: Explore Space with a Credit Card Reader hackaday.com

Hacker CharlesD repurposed a 1990s TRANZ 330 credit-card reader, which uses a Z80 processor, into an offline solar-system guide for telescope users. He replaced its UV-erasable ROM code, connected a GPS module and thermal printer, and programmed it to calculate planets’ azimuth and elevation; he also shared the source code.