When I was around 7 years old, our family was manufacturing ZX81, ZX Spectrum and Enterprise foil-keyboards, because the factory ones were just shit and died wi

When I was around 7 years old, our family was manufacturing ZX81, ZX Spectrum and Enterprise foil-keyboards, because the factory ones were just shit and died within a year or two. they were all the same design. 3 layers of plastic foil. 1 for horizontal wires, 1 for vertical wires to create a matrix and a 3rd sheet of foil between them with holes, so the horizontal and vertical wires can contact when pressed. before that, when I was around 6 years old, I remember my father was sticking round aluminum foil stickers on his finger and type directly on a keyboard made out of a PCB with a key matrix. The keys were the shape of 2 combs facing each other and you had to short them by touching them with the alu stickers on his finger. It was an AirComp II computer, iirc. I can't find any references to it online now...