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geekhack Community => Keyboards => Topic started by: allthumbs on Thu, 15 October 2015, 17:51:01

Title: Idle musing - Is there a switch that has a second actuation point?
Post by: allthumbs on Thu, 15 October 2015, 17:51:01
Let's say you want to send a Ctrl-C and on this hypothetical keyboard, that means you simply press C past this switch's normal bottom-out resistance. That is, there's normal bottom out with resistance for normal typing and then (past it) a true bottom out (for modified key presses).

Does anyone make a switch like that?

I imagine the user could decide whether to use this deeper actuation point for Shift or Ctrl or Meta....

Ah but then the keyboard would have to wait a little longer to know whether to send normal C vs the deeper altered C so you could never use this for gaming and the delay would annoy typists.

Topre plus a more complex controller would give you any number of activation points, though I'm guessing 2 is the max. Besides you'd need tactility before the deeper one so your finger would know whether to back off or push through.

Idle musing. Just thought I'd share.

Title: Re: Idle musing - Is there a switch that has a second actuation point?
Post by: njbair on Thu, 15 October 2015, 17:56:15
I don't believe any switches like this exist. If one did, it would require a third pin (at least--possibly a fourth) and a specially-made PCB to accommodate those pins.
Title: Re: Idle musing - Is there a switch that has a second actuation point?
Post by: chyros on Thu, 15 October 2015, 18:27:07
Yes, these exist! They are called double action switches and Alps made two versions of these:

http://deskthority.net/wiki/Double_action
Title: Re: Idle musing - Is there a switch that has a second actuation point?
Post by: davkol on Fri, 16 October 2015, 06:16:10
Key Tronic patented excessive-force sensing some time in the 90's—it was supposed to warn the user, when they smashed a key too hard, but Idk if it ever hit production. I guess it could be used as stated in the OP with some modifications.
Title: Re: Idle musing - Is there a switch that has a second actuation point?
Post by: FoxWolf1 on Fri, 16 October 2015, 07:38:00
Could always just use two switches:
(http://i.imgur.com/R8dHwh.jpg)
Title: Re: Idle musing - Is there a switch that has a second actuation point?
Post by: BrewCaps on Fri, 16 October 2015, 11:09:54
Dual shock switches are pressure sensitive.
Title: Re: Idle musing - Is there a switch that has a second actuation point?
Post by: Findecanor on Fri, 16 October 2015, 17:17:30
Yeah, any analogue switch could also have multiple actuation points. Topre, for instance has its actuation point set only as a threshold value and there have been analogue Topre switches displayed on trade shows.

Keys on musical keyboards (claviers. MIDI) also typically have two actuation points but they are supposed to always both be pressed and without you feeling them. The keyboard's controller measures the time between the two actuations to determine how hard you press the key, and thus how loud the note should sound.
Title: Re: Idle musing - Is there a switch that has a second actuation point?
Post by: chyros on Fri, 16 October 2015, 18:47:52
Keys on musical keyboards (claviers. MIDI) also typically have two actuation points but they are supposed to always both be pressed and without you feeling them. The keyboard's controller measures the time between the two actuations to determine how hard you press the key, and thus how loud the note should sound.
Oh wow, that's pretty clever :D . Are there any other types of device that use this kind of system? I think some game consoles can determine how hard you press a key for instance, but that might be due to press time than pressure.
Title: Re: Idle musing - Is there a switch that has a second actuation point?
Post by: Den441 on Sat, 17 October 2015, 00:02:21
Keys on musical keyboards (claviers. MIDI) also typically have two actuation points but they are supposed to always both be pressed and without you feeling them. The keyboard's controller measures the time between the two actuations to determine how hard you press the key, and thus how loud the note should sound.


My keyboard has this feature. If I hit a key really hard, it automatically goes caps. a a a a a A A A A A

It makes my caps lock text seem EXTRA ANGRY.  >:D
Title: Re: Idle musing - Is there a switch that has a second actuation point?
Post by: BrewCaps on Sat, 17 October 2015, 10:05:09
What keyboard is that?
Title: Re: Idle musing - Is there a switch that has a second actuation point?
Post by: richfiles on Sun, 18 October 2015, 00:24:13
There is a way to do a two layer PC board structure, and modify a Cherry MX (or compatible) switch to do this.

You need to remove the center post of the bottom of the keyswitch, to reveal the plunger. Small switches are then pressed on the bottom board by the plunger of the MX switch above them. The video makes it very clear how hit's done. Both the MX and the tiny switches on the second board are commonly available parts. Just takes a second PC board, in this case. If the switches on the bottom board are also tactile, then you could even have a switch with two tactile actuation points!

Title: Re: Idle musing - Is there a switch that has a second actuation point?
Post by: FoxWolf1 on Sun, 18 October 2015, 09:52:05
There is a way to do a two layer PC board structure, and modify a Cherry MX (or compatible) switch to do this.

You need to remove the center post of the bottom of the keyswitch, to reveal the plunger. Small switches are then pressed on the bottom board by the plunger of the MX switch above them. The video makes it very clear how hit's done. Both the MX and the tiny switches on the second board are commonly available parts. Just takes a second PC board, in this case. If the switches on the bottom board are also tactile, then you could even have a switch with two tactile actuation points!


I like it.

Something like this could be neat for gaming, too...having a second switch at the bottom would mean you could release from bottomed out and not have any delay created by the switch having to travel back upwards through its over-travel. You could also release and re-press a bottomed out key with a much smaller, faster motion.
Title: Re: Idle musing - Is there a switch that has a second actuation point?
Post by: Dernubenfrieken on Sun, 18 October 2015, 15:14:36
I like it.

Something like this could be neat for gaming, too...having a second switch at the bottom would mean you could release from bottomed out and not have any delay created by the switch having to travel back upwards through its over-travel. You could also release and re-press a bottomed out key with a much smaller, faster motion.

Yeah I could see it being used as a hardwired macro sort of thing, where you are frequently hitting B after A, but sometimes just want to hit A alone.