zx81 Keyboard...Sort of

ZX80 / ZX81 hardware and software requested for either sale or swapping
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jomac
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Joined: Tue Aug 05, 2014 8:18 pm

zx81 Keyboard...Sort of

Post by jomac »

Hi,
Can anyone remember, way back in the 80's you could get separate key switches with removable key caps where you could put your own lettering?

These keys looked very much like the keyboard on the old Sharp MZ80K computers. Does anyone have any of these or know where i could get some from?

Failing that, i would be happy with an external keyboard for the 81 if anyone has one cheap.

email: john (at) jomac.asia

John
sirmorris
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Re: zx81 Keyboard...Sort of

Post by sirmorris »

I'd be interested in some of these too. I've never come across them however :(
rune
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Re: zx81 Keyboard...Sort of

Post by rune »

I've been looking for these too for a long time. Found this today and have ordered 60 @ 15.44.

Will be a few weeks for delivery but will let you know what they are like when they arrive.

http://www.ebay.co.uk/itm/5pcs-Momentar ... 2c6ec7faa5

Does anyone has a wiring diagram to build a keyboard like the old DK Tronics? Extra keys would be nice too :)
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1024MAK
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Re: zx81 Keyboard...Sort of

Post by 1024MAK »

rune wrote:I've been looking for these too for a long time. Found this today and have ordered 60 @ 15.44.

Will be a few weeks for delivery but will let you know what they are like when they arrive.

http://www.ebay.co.uk/itm/5pcs-Momentar ... 2c6ec7faa5

Does anyone has a wiring diagram to build a keyboard like the old DK Tronics? Extra keys would be nice too :)
Those switches look like click PCB mounting switches, but with clear key tops. Click switches are available from various electronic suppliers, but I'm not sure about the clear tops being available.

For the standard ZX81 keys, wiring up a replacement keyboard is just about arranging the keys and wiring up as per the normal keyboard matrix.
If you want extra keys that perform the same function as existing keys (say an extra shift key), just wire in parallel with the existing key.

If however, you want extra keys that simulate two existing keys being pressed at the same time, it gets much more complex. The you either need key switches that have two separate push to make contacts, or a standard key switch and some electronics to do the same job. Or you can just copy the old Maplin keyboard circuit design.

Mark
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rune
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Re: zx81 Keyboard...Sort of

Post by rune »

Cheers Mark

they are coming from Hong Kong so will probably take 2-3 weeks to arrive. I couldn't find them with (or without clear tops) in the UK. Also buying from any of the major suppliers here adds a lot to the price when you pay postage.

No definite plans yet but I'm thinking about using a Speccy +2 case and putting a numeric keypad in the tape player hole.
sirmorris
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Re: zx81 Keyboard...Sort of

Post by sirmorris »

From just a very quick scan of a few images of zx81 keyboards it appears that, on the whole, the only special function keys that were commonly available were those that only require shift + one other key to trigger. So, FN [shift + newline], RUBOUT [shift + 0], GFX [shift + 9], etc. etc. A cursor block is possible.
Moggy
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Re: zx81 Keyboard...Sort of

Post by Moggy »

sirmorris wrote:I'd be interested in some of these too. I've never come across them however :(
The Crofton adaptakit and Maplin keyboard use the removable clear key top keys, I think I may have one going spare somewhere Charlie if you could use it Lord knows I owe you enough :lol: .

The Kaydee keyboard has a repeat key fitted using shift + repeat key to operate.
XorA
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Re: zx81 Keyboard...Sort of

Post by XorA »

Those keys on Pokemon's keyboard PCB would be really nice. Mine are all packed away in a box so I cannot check if they would fit!

G
rune
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Re: zx81 Keyboard...Sort of

Post by rune »

XorA wrote:Those keys on Pokemon's keyboard PCB would be really nice. Mine are all packed away in a box so I cannot check if they would fit!

G
Something like these...

http://www.ebay.co.uk/itm/50-Pcs-Electr ... 43bbc99fde

1.70 for 50 and that includes postage.
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questarian
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Re: zx81 Keyboard...Sort of

Post by questarian »

I had the same idea and used those small clear cap keys mounted on a perf board. They're the right size to fit with in the ZX keyboard area, but the problem with the ones I recieved was that they had a lot rotational play in the key heads... They really twist around... Out of 100 switches a little more than a third of them were stable enough to use for a keyboard.

Image

I've been looking to build a ZX keyboard in panel enclosure using these:
http://www.ebay.com/itm/140686450390?_t ... EBIDX%3AIT

-John-
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