A Hall Effect Keyboard Is Nigh Thanks To Grassroots Effort

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anbello262

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If all the benefits turn out to be true, we could be seeing the start of a mechanical keyboard replacement. If not, well, it will be a great gadget to show off.
 

bit_user

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Before ordering white on bamboo, give some thought to how it will age.

I used to pop off the keycaps and clean my keyboards once every year or so. Lately, I can't be bothered. Dust & dirt gets on the sides of the keys, even though I'm pretty clean and rarely eat at my PC.
 

mikeebb

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Interesting. Early Radio Shack (Model 1, possibly also early 2 and 3) had Hall-effect keyswitches. They *did* require debounce routines - early ROMs didn't have one or a good one, resulting in keybounce unless an add-on routine was used. Permanently fixed in the ROM replacement that provided upper/lower case, and in the DOS's.
 

alextheblue

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I thought bounce was an issue mostly with mechanical switches and relays (some designs more than others). Where the metal contacts physically strike and "bounce" away from each other briefly, chattering and causing extremely brief intermittent contact until they settle. This can be filtered or multi-sampled out.

I can't see this sort of thing being an issue with a hall effect switch. Are you SURE the keyboards you're talking about weren't mechanical?
 

mikeebb

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At this remove (Model 1 era was late 1970s) it's hard to be absolutely sure. I don't know where to find the manufacturing data if in fact any were kept. But I was told at the time that they were Hall-effect keyswitches, and in more than 10 years I only had to replace one (became mechanically sticky after about a year - yes, keyswitches were individually replaceable, and this was probably infant mortality). I suspect the keybounce in early machines (mostly Level 1, I never really had it in Level 2 BASIC) was related more to poor software than the switches, and once we moved to (TRS-, L-, New-, etc.)DOS there was never a keyboarding issue. Should also note that they were not "clicky" at all. Simple thunk on reaching the end of the (rather long) key travel.
 

GeoffCoope

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Without sounding like a bug bear, what are the real world benefits of using this?. Saying it is "really fast" has no meaning without statistics. Is it a gamers keyboard in this respect? What about simultaneous key presses? Thanks.
 

Chyrosran22

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I could identify the switch if you gave the precise model name or especially a picture of the keyswitch. Actually, even just a picture of the back of the PCB would do in this case. I ask because I'm not completely sure what model you're referring to. If you mean the TRS-80 Model 1, that didn't come with Hall effect switches (it used SKCC conductive switches).

 

Chyrosran22

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The benefits are all derived from the Hall effect sensing mechanism. Because this doesn't require physical contact between most of the parts, there is less friction, and you get a smoother switch action, and because it's the closest you can get to solid-state switching and the parts (basically just a magnet) are super-reliable, the keyboard becomes extraordinarily durable in theory.

 

mikeebb

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The Model 1 keyboard was anything but fast - the whole computer ran on a 1 MHz Z-80, after all, and the initial package came with only 16K of RAM (later expanded to the maximum of 48K). Nobody did modern gaming with it, though I could play a couple of black/white block-graphics games, such as a clone of Pac-Man that could be played with the arrow keys, and version 1.0 of Flight Simulator (from a casssette tape). Mainly, it was built for home & small business use, and hobbyists, and the keyboard had the advantage of feeling really good - like a good electric typewriter. It worked as well in 1991 (when I replaced it with a DAK PC clone for compatibility with the office) as it did on Day One (1978 iirc). Used it frequently with a couple of word processors and Visicalc 1.0, as well as a financial package done in Basic and the occasional login to work or Compuserve (300 bps acoustic modem).

Main point, I think, was that unless something mechanical (such as a return spring or a warped key stick) failed, the keyboard was essentially indestructible and, if something did break (like that one switch for me), it could be easily repaired. At modern prices, if a keyswitch breaks, it's more cost-effective to replace the whole keyboard...
 

mikeebb

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I could identify the switch if you gave the precise model name or especially a picture of the keyswitch. Actually, even just a picture of the back of the PCB would do in this case. I ask because I'm not completely sure what model you're referring to. If you mean the TRS-80 Model 1, that didn't come with Hall effect switches (it used SKCC conductive switches).
It was a very late-production Model 1, just before it was dropped. If the switches *were* conductive, they (except for that one, early on) were extraordinarily reliable and felt very good - not characteristics of conductive switches at the time. Again, I was given to understand by the TRS-80 magazines and such that they were Hall-effect, but am probably wrong.
 

Chyrosran22

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Well the various TRS-80s came with various keyboards and various switches, at some point they even used rubber domes. The model best-known in the community ( http://www.nightfallcrew.com/12/10/2012/radio-shack-trs-80-model-1-video-display/ ) came with SKCCs, and a nearly identical-looking model came with Hi-Teks. Both are conductive switches.

 
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