reverse force switch interest

zlice

19 Feb 2020, 01:24

Would anyone be interested in a "reverse force" switch?

Example of what I mean in the pictures.

There's a few things every typical switch does that this type of switch would do differently
  • Switches are supposed to start their force curve at the top rest point. They rarely do, I find there's half out of every bunch I buy that have an extra 'tic' before starting their rated force curve. This switch would always have the highest point of resistance at the top.
  • Most normal switches attempt to "increase" force as you go down to prevent you bottoming out. I find this doesn't work for me and other's have asked the question as well - if bottoming out is normal. This switch would have shorter travel overall and not attempt to prevent you from bottoming out. There would be little fatigue since the highest resistance will always be at the top resting point of the switch.
  • The spring 'ping' would be eradicated
Does this concept interest anyone?
The current forces I have would be around the 50g mark and 30g mark on the reverse picture.
Attachments
reverse
reverse
force_graph_reverse.png (16.38 KiB) Viewed 2893 times
normal
normal
force_graph_normal.png (16.65 KiB) Viewed 2893 times

User avatar
SneakyRobb
THINK

19 Feb 2020, 01:42

Hrm interesting. Part of the force curve is that you are putting energy into typically a return spring and it stores it up to return the key back up. I am not sure if it is possible to have a force curve as you want using normal metal springs. I can't remember how Hooke's law works, its been many years.

I wonder if something like a minature solenoid or electromagnetic slider instead of a return spring would work for your purposes? Imagine if each switch had a small solenoid under it with a sensor that increased or decreased resistance based on the slider position and then would also be able to return the key to resting position

I am sure there is a simpler solution though, I am not a scientician

zlice

19 Feb 2020, 01:54

I have it working.
That's why I'm checking if anyone is interested =)

User avatar
PlacaFromHell

19 Feb 2020, 03:30

SneakyRobb wrote:
19 Feb 2020, 01:42
Hrm interesting. Part of the force curve is that you are putting energy into typically a return spring and it stores it up to return the key back up. I am not sure if it is possible to have a force curve as you want using normal metal springs. I can't remember how Hooke's law works, its been many years.

I wonder if something like a minature solenoid or electromagnetic slider instead of a return spring would work for your purposes? Imagine if each switch had a small solenoid under it with a sensor that increased or decreased resistance based on the slider position and then would also be able to return the key to resting position

I am sure there is a simpler solution though, I am not a scientician
You can just take a sort of magnetic piston and use it like a spring. The far they are the magnets, the less force you have to use to make they go further.

User avatar
ZedTheMan

19 Feb 2020, 04:07

zlice wrote:
19 Feb 2020, 01:54
I have it working.
That's why I'm checking if anyone is interested =)
I am certainly interested in the implementation.

Is it contact-based?

squizzler

19 Feb 2020, 11:47

zlice wrote:
19 Feb 2020, 01:24
Would anyone be interested in a "reverse force" switch?

Example of what I mean in the pictures.

There's a few things every typical switch does that this type of switch would do differently
  • Switches are supposed to start their force curve at the top rest point. They rarely do, I find there's half out of every bunch I buy that have an extra 'tic' before starting their rated force curve. This switch would always have the highest point of resistance at the top.
  • Most normal switches attempt to "increase" force as you go down to prevent you bottoming out. I find this doesn't work for me and other's have asked the question as well - if bottoming out is normal. This switch would have shorter travel overall and not attempt to prevent you from bottoming out. There would be little fatigue since the highest resistance will always be at the top resting point of the switch.
  • The spring 'ping' would be eradicated
Does this concept interest anyone?
The current forces I have would be around the 50g mark and 30g mark on the reverse picture.
My initial thought is that you have set out to engineer a mechanical switch that has the general behaviour of generic rubber membrane boards. Those seem to require some force at the top to collapse the rubber dome, then less force after that point till you bottom out.

Frankly I don't see the appeal of what you propose, but maybe I am missing something?

daguil68367

19 Feb 2020, 15:14

There seems to be a switch that already has this kind of force curve:

wiki/Burroughs_Opto-Electric

zlice

19 Feb 2020, 15:20

ZedTheMan wrote:
19 Feb 2020, 04:07
I am certainly interested in the implementation.

Is it contact-based?
Sadly, yes.
Could do a contact-less version but that would kill compatibility with CherryMX and the like. (Different board required)

zlice

19 Feb 2020, 15:23

squizzler wrote:
19 Feb 2020, 11:47
My initial thought is that you have set out to engineer a mechanical switch that has the general behaviour of generic rubber membrane boards. Those seem to require some force at the top to collapse the rubber dome, then less force after that point till you bottom out.

Frankly I don't see the appeal of what you propose, but maybe I am missing something?
I see your point. It feels more sharp than a dome keyboard comparing the two.
Feels like I expect a mechanical switch to feel with the force at the top and an immediate "aha - it pressed".

zlice

19 Feb 2020, 15:25

daguil68367 wrote:
19 Feb 2020, 15:14
There seems to be a switch that already has this kind of force curve:

wiki/Burroughs_Opto-Electric

Awesome, was looking for anything different. Force curve looks similar.

PlacaFromHell has the right idea.

User avatar
ZedTheMan

19 Feb 2020, 16:27

zlice wrote:
19 Feb 2020, 15:20
ZedTheMan wrote:
19 Feb 2020, 04:07
I am certainly interested in the implementation.

Is it contact-based?
Sadly, yes.
Could do a contact-less version but that would kill compatibility with CherryMX and the like. (Different board required)
I actually consider that an upside for a new switch as that compatibility is crucial for getting stuff off the ground without a massive group buy or the like.

User avatar
SneakyRobb
THINK

19 Feb 2020, 17:21

daguil68367 wrote:
19 Feb 2020, 15:14
There seems to be a switch that already has this kind of force curve:

wiki/Burroughs_Opto-Electric
Damn there you go. Much simpler than my idea

Post Reply

Return to “Keyboards”