Two-Point Actuation Keyswitches?

[mil]

I've been doing some research trying to find a switch that has two points of actuation -- I.e. you would press down the keyswitch and mid-way you would hear a click for the first point of actuation, then you would keep on pushing down and there would be a second point of actuation with a second click (maybe around bottoming out). Furthermore, you would be able to send a separate keycode for each point of actuation.

The closest thing I can think of mechanical-wise is a pot or a slider switch, but neither are spring-based or momentary as I would like.

Do the types of switches I described exist, if so what are their names? Or am I just dreaming?

[Melvang]

I hate to say it but the only thing like that I have seen is the automatic roll all the way down deal on power windows in cars.  The one in my Buick has a definate tactile point at momentary down and bottoms out for the "go all the way down" selection.

[jacobolus]

Yes, there are a few rare old keyboards (from the 60s–80s) with such switches. If you’re curious about them you should hop on IRC and ask HaaTa, as he has hundreds of keyboards, I think including a few of this type.

There’s a guy at Deskthority who has an old Adler typewriter with old Cherry switches, including a couple with this behavior. http://deskthority.net/photos-videos-f8/triumph-adler-typewriter-cherry-m6-gabriele-8008l-t6648.html

There’s no click though. You can just tell that you’ve passed the first actuation point when the linear switch suddenly gets a whole lot stiffer.

[AKmalamute]

I would really like to see switches with this behavior, and let me tell you why / where I've seen them:
PS/2 controllers.

The buttons and analog joysticks all have, at least ostensibly, a range through which you can choose "how much" you're pushing down.

Mind you, it's completely useless because it happens within an almost instantaneous moment of the key's throw, and something akin to 3/4ths of the movement is past "fully depressed" -- but many video games could benefit from having two, or three or four states.

If it doesn't derail OP's question too much, how might other GH'ers use existing keyswitch technology to make a working, useful, playable PS/2 (or other console) controller?

[False_Dmitry_II]

The problem is then you have to get everyone to code that. It's one thing if it's someone mapping bottoming out W to press shift (which in this example is run) in order to just use one key, but another if it's supposed to be built-in. I've once played a game on the original xbox where all inputs only occurred on the second bottoming press. I learned just how hard you had to press to get to that last one, and eventually just plugged in a PS1 controller which has no input range.

PS: Do you mean PS2? Or PS/2? Different things, they are.

[blackbox]

Second actuation point for backspace+shift+letter/charater. So when you type with the second actuation point you write in caps.

[jacobolus]

Take a look at

[False_Dmitry_II]

I'm surprised that all fit in the case as usual. One problem I can think of is that some games force you to use either controller or keyboard and mouse and not all as inputs for one character like that.

[dorkvader]

Yes, there are a few rare old keyboards (from the 60s–80s) with such switches. If you’re curious about them you should hop on IRC and ask HaaTa, as he has hundreds of keyboards, I think including a few of this type.

There’s a guy at Deskthority who has an old Adler typewriter with old Cherry switches, including a couple with this behavior. http://deskthority.net/photos-videos-f8/triumph-adler-typewriter-cherry-m6-gabriele-8008l-t6648.html

There’s no click though. You can just tell that you’ve passed the first actuation point when the linear switch suddenly gets a whole lot stiffer.

These seem to be found primarily in typewriters. There is also the marquardt butterfly.

[Parak]

Alps used such switches for enter, backspace, and space keys on some older canon typewriters. Tactile actuation midway and a click when pressed all the way down. Requires a fair bit of force for that second press however, something like > 100 grams.

[mil]

Thanks for the input guys. I feared nothing existing quite like a 2-point actuation switch.

The reason I asked to begin with is that I'm interested in building a chording keyboard where you don't move your fingers, i.e. 5 buttons per hand and you would just push up and down on the keys in different combinations for keys. Beyond prototyping the components, I don't think I'd be able to source mech components 

[blackbox]

I know its not the same thing but if you want to build an split keyboard you could build yourself an ergodox.

[dorkvader]

The reason I asked to begin with is that I'm interested in building a chording keyboard where you don't move your fingers, i.e. 5 buttons per hand and you would just push up and down on the keys in different combinations for keys.

Hmm, this sounds a lot like the datahand actually. There's a project to recreate it now:
http://geekhack.org/index.php?topic=41422.0

a picture
http://deskthority.net/photos-videos-f8/datahand-t2384.html

a lot of excellent mods
http://geekhack.org/index.php?topic=12212.0 (coming soon)

[shaaniqbal]

The Synaptics ThinTouch was supposed to do something like that I think (push a key harder to get a capital letter). Look at the video here, 33 seconds in "Force sensing". http://www.synaptics.com/en/thintouch.php

What about a completely analogue backspace key, where the harder you press it the more quickly it backspaces?

The reason I asked to begin with is that I'm interested in building a chording keyboard where you don't move your fingers, i.e. 5 buttons per hand and you would just push up and down on the keys in different combinations for keys.

You could check out ASETNIOP and my project, T9-QWERTY.

[Daniel Beardsmore]

I created this category on the wiki for them, but since most of them aren't on the wiki to begin with, the only one listed thus far is the Alps SKCLKB (still present in the 1994 Alps catalogue, surprisingly enough):

http://deskthority.net/wiki/Category:Double_action_switches

Cherry M6/M7 had double-action variants, plus of course those mentioned above. I was surprised just how many switches of this type exist.

http://deskthority.net/wiki/Double_action

Completing the above category is a nice challenge for someone.

[dorkvader]

Cherry M6/M7 had double-action variants, plus of course those mentioned above. I was surprised just how many switches of this type exist.

I wonder how many exist that were not used in typewriters. I mean, the typematic repeat of the IBM selectric typewriters has a sort-of dual action functionality, so I wonder if that's the reason why dual action switches are so prevalent in typewriters (and nowhere else) or if it predated even that and IBM was just going with the flow on that one rather than setting the trend.

In other words: I expect that looking at electric typewriters will yield fast results.

[Daniel Beardsmore]

The ones found so far mostly if not all appear in typewriters.

[clickclack123]

From here:

Cherry MX with extra contacts for velocity sensing

Made with two pins of a female header and a cut sliver from the gold plated disc inside a 12x12mm tactile switch.

Cool idea IMO.

[blackbox]

From here:

(Attachment Link)

Cherry MX with extra contacts for velocity sensing

Made with two pins of a female header and a cut sliver from the gold plated disc inside a 12x12mm tactile switch.

Cool idea IMO.

Cool mod(But it has unnecessary much wire unisolated).

[Findecanor]

With Cherry MX, you could cut off the knob on the bottom of the switch so that the bottom of the slider can hit a switch mounted upside-down on the opposite side of the PCB.

There was also a guy who modified his Cherry MX keyboard to make the WASD keys also work as an analogue joystick, using a similar arrangement.

[ch_123]

IBM designed a variant of the beam spring which two actuation levels depending on how far you pressed the key, but there was only one tactile point.

http://www.google.com/patents/US4274752#v=onepage&q&f=false