New Stuff For Old Stuff :: Blog

A  ZX81's keyboard is frustrating to use. Especially for games. One too many times, you find your finger isn't quite over the pad when you have to make that crucial jump... It's easy to use an emulator, but personally I don't get the same buzz. My first computer, probably in '82 was a secondhand ZX81 which had been screwed to a board along with some kind of aftermarket keyboard (which really wasn't very good). So for that reason I feel perfectly OK about sorting myself out with something similar now. After looking at many options (including the ZX-Key, which looks excellent  and the Minstrel keyboard which has tactile switches ) I noticed while recapping a Spectrum +2 that the keyboard connections are very similar to the 81's: There are more lines because the later spectrums have many more keys. But some study of the matrix diagrams made me think that they were compatible* if you take the first five and the first eight lines from those ribbons.

T he ZX81 was my first computer. Mine was screwed to a board with a terrible external keyboard, and I was proud of the fact that someone had fitted 2k of RAM. It was my introduction to BASIC and machine language. Let's not forget that the humble zeddy is a vehicle for a Z80 (which has 16-bit features) running at >3Mz. (Of course you can only harness that amazing power in fast mode, ie without display output, because much of the CPU time is usually used to generate the display.) Other than buying some kind of box that will convert the TV signal (with which I had limited success), it's possible to perform surgery to convert the output to composite, which modern displays may be more likely to display (but still maybe not in the case of the ZX81s with the older ULA). Here are three methods - rewiring (cost zero), using some simple components (cost pence) and a purchased modification (still less than a tenner.) With the newer issue 81 it's possible to simply tap the