The Sinclair ZX81 was a masterpiece of Sir Clive’s desire to get the most out of the least hardware, being about as minimalist as it was possible to get and still be a home computer in 1981. As such it has a keyboard, a Z80, TC and cassette interfaces, 1K of memory, and that was it. There were any number of add-ons for it, but if you were a 1980s kid the chances are you couldn’t afford them. So 45 years later here’s [adam.klotblixt] with OpenSpand — every ZX81 expansion you could think of, all in one!For a start there’s a RAM expansion. Not the paltry 16K of old, this is user-configurable and has the whole 64K address space minus the ROM to play with. Then there’s SD card storage, hijacking Sinclair BASIC’s LOAD and SAVE commands. It’s got high-res graphics, emulated sound chips, a joystick port, serial ports, a choice of ROMs, and a composite video output. Perhaps the only thing it doesn’t have from back in the day is a printer interface, but we’re sure the serial port could be pressed into service somehow.It does this all as you might expect these days, with an RP2350 emulating the real parts. The microcontroller disables the onboard RAM and ROM and emulates those too, such is the disparity in power between it and a Z80. We would have done anything for this expansion, back in the day.The ’81 features here quite often, most recently in a look at Sinclair’s own RAM expansion.