I am not a physicist or electrical engineer, but wouldn't all that magnetism swarming (because it would be a swarm of discreet fields, no?) over a small area be an electronic nightmare?
On the other hand, some people like magnets for arthritis, so you could get your therapy as you typed!
Here's something with magnets in:
http://deskthority.net/photos-videos-f8/univac-f-1355-00-t6489.html
Not what you had in mind, but still, you're not the only person to consider using magnets in that sort of way.
I am not a physicist or electrical engineer, but wouldn't all that magnetism swarming (because it would be a swarm of discreet fields, no?) over a small area be an electronic nightmare?
On the other hand, some people like magnets for arthritis, so you could get your therapy as you typed!
I am not a physicist or electrical engineer, but wouldn't all that magnetism swarming (because it would be a swarm of discreet fields, no?) over a small area be an electronic nightmare?
On the other hand, some people like magnets for arthritis, so you could get your therapy as you typed!
How can this be good for your other electronics peripherals? As a perpetual klutz I am extremely sensitive to the possibility that I screw up my computer doing something silly. One big electromagnet sounds like a hard disk killer to me - and I sometimes put hard disks on my desk.
Opposing magnets would make very neat key switches IMO. But I wonder how much would they cost?
Those are expensive
You need $1 per magnet, meaning you need 2 for a switch.
Ouch.
Will definitely feel different to springs. Springs have an almost constant increase in resistance, whereas opposed magnets have an increasing rate of increase of resistance (square law). You can tune this "rate of increase" by adjusting the distance and magnet strength (stronger magnet at further distance = same initial force, but slower increase in force).
It may be hard to get a set of magnets with consistent enough strength between them and it'll take some experimentation to get the right distance and magnet strength, but it's possible. Not sure I'd like the feeling, though. I like the linear increase of springs. It could feel really odd, with a soft initial press and rapid increase in resistance. Kind of organic...
You'd need around 2g (stem and keycap mass) + desired initial press strength at the top and will have to have some kind of retention system for the caps. An MX slider and case may work well. Magnets could be mounted somewhere on the slider and under the case bottom. If the magnet is 2mm or smaller and less than 0.8mm thick it will fit on the pole that goes into the tube in the lower case. I suspect it won't be strong enough at that size, though, unless the lower magnet is really strong. You could also try a thicker magnet (or even a cylindrical one) and trim the end of the pole to match.
Those are expensive
You need $1 per magnet, meaning you need 2 for a switch.
Ouch.
Those prices were for a pack of 10 magnets.
I guess I'll add my 2 cents here...
I was thinking about reed switch boards I had posted about a month ago from Zbrojovka Brno. They use a pretty simple linear mechanism - a single spring and a reed element soldered on a small "elevated" plate. It is activated by a slider-mounted magnet. In Unitra-Polam switch they've put a magnet... inside the cap. I guess it would be possible to combine this with maglev concept (both ideas utilize magnets) thus obrtaining an ultimate solution :) Electronics in a keyboard like this would be 100% isolated from the above, thus making it 100% spill/dust resistant. Here's my quick MS paint job:Show Image(http://s23.postimg.org/r9pj4f66j/maglev.gif)
It's a very simplified schematic without paying much attention to small details... And there should be "isolation" instead of "insulation", but I think you get the idea ;) After the cap is pressed, the magnet descends down and activates the reed switch. You could use different magnets to obtain different forces, and maybe even add something to achieve tactility. You can use different "caps-latch" mechanism (I've copied the "space invader" more or less in my gif).
Hmmm... Why mougrim? I mean in Zbrojovka boards and in MK45 / Elwro Junior they activate after a magnet reaches a certain proximity point in space, and they "release" after said magnet leaves this space - and only after that they are ready to register another "key press". You don't have to be that precise I guess...?
As far as experimenting with this I was thinking about using magnets inside of cherry switches. From the measurements that I got from mkawa 1/8" diameter magnets should fit inside the spring.
So rather than calibration, I think there might be a problem with the magnetic field direction in respect to the reed switch.
I was just going to explain it, but since I do finite element stuff anyways...might as well show you some actual simulations of the magnetic fields between two equal strength magnets.
These are 2D slices through the center of 2 cylinder rare earth magnets setup for levitation (opposing North and South poles).
CloseShow Image(http://i.imgur.com/7PHoU8v.png)
FarShow Image(http://i.imgur.com/CcErUVe.png)
For either a hall effect sensor or reed switch you are using a change in the magnetic field strength (reed switches use a much stronger change). As shown above, the magnetic field around where you want to place the reed switch doesn't really change at all... Yes the magnitude changes, but overall, there is a magnetic field already going in the direction you want whether the magnets are close or far (so the reed switch will always be closed :P).
Using a reed switch is much easier overall to implement (I'm familiar with the hall effect issues though), so keep trying :thumb:
May be sufficient, but it's highly dependent upon the strength of the magnets and peak magnetic field required for the reed switch. Switching out magnets will likely be hard.Yeah. I see need for a serious modeling here.
Thanks for the feedback guys! Great pictures HaaTa! I have a quick question: what is the distance scale on them? I mean if you could draw 1mm distance on it, that would make a good point of reference :) I guess it isn't that much of a problem, because you can always move the reed switch in horizotal space wherever you want to to suit your needs. It can be even placed behind a very thin plastic wall, so when the magnet descends, it would almost "touch" the reed... Thanks to your explanation, now I understand why you can hear metallic "click" sound on some Unitra-Polam switches! That's because some of the magntes are indeed touching reed elements! A good way to be sure that it qould register :thumb:
Now I'm ready to make new concept sketch, this time with actual dimensions. Gosh, now I wish I would have a caliper! That way it would be easy to measure reed switch dimensions or plastic thickness for example :) I wonder which kind of magnets would give a "nice" kind of feel... Now I'm thinking where I could find ANY magnets and experiment a little with some rubber dome switches - you know, the cheapest ones, I think they are best suited for experimenting thanks to the very simple design!
Good luck to you :) When you'll become a greatest keyboard designer of the world, just give us 1% of the shares :)
Maybe you should apply for a patent on this type of switch.
It's been a very busy week... Got a short news update:
1) 240 neodynium magnets arrived
2) I've purchased 10 reed switches online to prototype my idea, they haven't arrived yet.
3) 5 minutes ago I've finished installing one pair of magnets in a beaten up "Turbo Plus" rubber dome from KME.
4) Two words: IT WORKS.
5) Switches are 100% contact-less, without the need of any reeds.
6) I've to clean this board and install all magnets, so expect some pictures + a video tomorrow at best. Maybe I'll run into some new problems... It's not that easy :/
7) It's not a "magnet touches reed element" sound that I was hearing in my MK45 and Elwro - it's the sound of the reed element itself, when it's getting into a close proximity to a magnet. I was a total idiot and had no idea what I was talking about.
8 ) I've tried to search something up on those vintage magnetic switches... Now I know A LITTLE more I think... Zbrojovka Brno-s utilize Honeywell HAL effect clones ("a holy grail of keyboards" ;) ), MK45 and Elwro use reed switches. I know, for some of you out there is common knowledge, but it wasn't that obvious for me up until now!
Looking forward to hear from you simon_C! Let's get this on!
Great work! Really interested in seeing the final results!
So I was thinking -- ignoring the EM field nightmare it would be -- why not make one with electromagnets? It'd be expensive as f**k, but you could create adjustable keyforce keyboards, possibly even with an electronically-generated tactile point. (E.g. once the reed switch or hall effect sensor trips, reduce the magnetic field strength. Or increase it. Whatever you want.)
Yeah, I just mixed up words... "idea" with "thought". You know, my standard translation issues. I was talking about this power-on -> caps up thing!
EDIT: I've just added some pictures here (http://utensilia.tk/urzadzenia/kme_kb-9001re_maglev.html). Nothing new, really :) I'll try to assemble another board with circle magnets in two weeks!
just be careful with the magnets and your computers fellas. magnets and computers are not always friends. you can damage a cables fairly easy with a magnet.
Hard-drives contain NdFeB magnets of astonishing strength. FAR BEYOND anything that can be bought on flea-bay and similar.
These are the voice-coil magnets; for moving the heads. I doubt a mag-lev keyboard would damage a drive, assuming you could ever pry them apart again...
Also - Reed switches ? why use 1850's tech when 1950's Hall-Effect sensors are SO much better (no switch-bounce, just a clean analog increase in voltage).
And - since its an analog value - you could set each switches actuation point in software, individually.
My first thought is simpler then reed switches or Hall effect devices.
Moreover it is easiuly testable. Replace the contacts with a thin copper wire running from the toip of the switch to the bottom.
When a magnet passes by, it will induce a pulse through the wire which a controller can use as a keypress.
Too costly, too energy-consuming.
Too costly, too energy-consuming.
Apparently not:
http://www.cnet.com/uk/news/darfons-super-thin-maglev-keyboard-will-make-notebooks-even-slimmer/