ZX81PLUS35 ZX81 clone: Difference between revisions
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Even though I was hospitalized, then immobilized for several months (in the months of June July and August 2014) due to an operation on my leg, I still managed to work a bit on the layout of the ZX14. And on November 25, 2014 The layout work reached 100% connectivity. Here is a preview of how the work was progressing then. Clean-up, optimizing and copper filling followed somewhat later. The picture below was actually a screen shot from a gerber viewer of how the board looked in September 16, 2014. | Even though I was hospitalized, then immobilized for several months (in the months of June July and August 2014) due to an operation on my leg, I still managed to work a bit on the layout of the ZX14. And on November 25, 2014 The layout work reached 100% connectivity. Here is a preview of how the work was progressing then. Clean-up, optimizing and copper filling followed somewhat later. The picture below was actually a screen shot from a gerber viewer of how the board looked in September 16, 2014. | ||
Some weeks later the cleanup was ready, and this is a picture of how the PCB will more or less look like, when it is finished. Note the old PCB layout still has the, nor abandoned name "ZX81+34". | |||
[[File:Component placement 16 September 2014.png|500px|thumb|left]][[File:ZX81+34.png|400px|thumb|left]] | |||
[[File:ZX81+34.png| | |||
==Keyboard (ZX14/ZX15)== | ==Keyboard (ZX14/ZX15)== | ||
Revision as of 00:33, 16 January 2015
The ZX15 (previously called the ZX14) retro homecomputer is a much improved Sinclair ZX81 [1] clone built with the modern materials techniques and components of 2015.
it will be fully open sourced effort (but note that the original design of the ZX81 is still owned by Amstrad)
As for now comments and questions on the design can be made here [2] (raspberry PI forum off topic section) :-)
3D Preview of early ZX14
Before I even designed the PCB I made a mockup with Altium. Here are two (3D rendered) previews of the early ZX14 board, to the right a small preview of the complete system, including how I envisaged the whole system with keyboard would look like
Schematic ZX14/ZX15
The latest schematic (.PDF) can be found here: File:ZX14 schematic.pdf
there is also a color coded schematic (.PDF), it can be found here: File:Color coded ZX14 schematic with eprom support.pdf
note that SMT components are depicted purple, and PTH ones green.
Layout ZX14
Even though I was hospitalized, then immobilized for several months (in the months of June July and August 2014) due to an operation on my leg, I still managed to work a bit on the layout of the ZX14. And on November 25, 2014 The layout work reached 100% connectivity. Here is a preview of how the work was progressing then. Clean-up, optimizing and copper filling followed somewhat later. The picture below was actually a screen shot from a gerber viewer of how the board looked in September 16, 2014.
Some weeks later the cleanup was ready, and this is a picture of how the PCB will more or less look like, when it is finished. Note the old PCB layout still has the, nor abandoned name "ZX81+34".
Keyboard (ZX14/ZX15)
Early on I have was also busy designing a solution for the keyboard. My solution was to use commercially available cheap 6x6mm buttons, which (with some effort by bending the pins a bit) can be mounted on an EuroCard sized piece of 1/10"raster perfboard, the result would like something like the picture on the left.
Here is the schematic of the keyboard: File:KB matrix schematic.pdf
I also designed a new keyboard overlay suitable for such a keyboard with the keys going through holes in the overlay. Here is a drawing showing how it would look:
Here is a .PDF version that should be correctly scaled when printed on A4 paper.