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Old 24th Apr 2018, 6:49 pm   #23
SiriusHardware
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Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,484
Default Re: MK14 schematic revisions

Thanks for the info about KICAD. I run a mixture of Windows and Linux here so it's good to have the choice.

Actually the reason I asked is that I have for years been interested in making an MK14 -keypad- PCB, as the task of wiring up a bit of veroboard full of switches is incredibly tedious, especially given the weird nonstandard keypad matrix adopted by S.O.C. It would make sense for it to be laid out for at least two alternative types of switches, maybe cheap 'tact' switches and more luxurious full-travel switches - if it is even still possible to buy those now, and at sensible prices.

As you've probably realised keypads are the bane of the original MK14, with many original MK14s having faulty or missing original keypads. I would like to be able to make an easily replicable version of the 'floating' keypad I have on mine, with 12 blind pads on the underside at the right hand edge - these could either be taken directly to the PCB via descending wires underneath the keypad for a neater look as they are on mine, or alternatively they could be carried out to the right hand edge of the PCB via a 12-way 0.1" spaced ribbon cable going to a 12 way edge connector for a 'fast fit' solution, in which case you'd just fit the keypad with four bolts and spacers, plug the edge connector in on the right hand edge and <Bam> you have a working MK14 keypad again.

As brilliant as Karen's PIC14 absolutely is, I'm not sure that it has onboard nonvolatile program storage, nor have I measured the current drain - probably a bit too heavy for a PP3 (9V) battery - so I'm not sure that it would be truly practical for portable use.

I'm informed (although I have not seen it) that there is a very faithful MK14 emulator for Android - that might be more practical for the commute.
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