Re: Ideal keyboard design and configuration
 

That would be #unlike ;)

It's a good idea, as it makes it simpler to build the keyboard. No more question on how to make the contact on keys, and it allows changing the keymap easily an at any time.

There is still the slider mechanism to build, and more importantly there is a need for something on top of the e-paper to "materialize" the key and have the feel we need (a "push button" feel). This can be a transparent layer added on top of the epaper which has bumps at the places where the key will be displayed on the screen.
Then, to change from a 4 to 5 row layout, only this top layer would need to change. A gaming pad with analog pad could also use a third one.

Then, a driver must be found that can handle multi-touch (at least for key combinations) and palm detection, and some level of code on the device to update the e-paper screen with the current layout (the image could change when symbol or shift keys are pressed, if the screen is fast enough which I am not sure), and to decode finger position on the touch screen as key presses.

Do you know of such a cheap e-paper screen with resistive multi-touch digitizer ?

Re: Ideal keyboard design and configuration
 

Ha.

True it is very easy! You just need:

And lets not forget:
And then your done!

Re: Ideal keyboard design and configuration
 

I am thinking that the physical keys might be very similar to the N900 keyboard, but transparent (of course) and with a few more rows and columns. Preferably with a similar feel when pressing the keys as what the N900 has, though I might like it a bit softer than the N900 is right now.

If the transparent physical overlay covers the entire e-ink base of the keyboard, there is no need of palm detection. The transparent physical keys will likely have some form of support that rests on the e-ink surface at regular intervals, and those support points will need to be ignored (even if they wiggle slightly when the keyboard is used). If a multi-touch capacitive touch layer is used, the key-supports could simply be non-capacitive to avoid that issue.

Oh, and there will have to be lighting of some sort too!

Re: Ideal keyboard design and configuration
 

The driver could also permit apps to upload any picture they want to the e-ink surface, so that games and other input-intensive apps can present icons for various actions on the keys, rather than just letters.

Re: Ideal keyboard design and configuration
 

You forgot the "cheap" and "easily availlable" in your search link...
I didn't have 2 hours to spend to compare what exist (I already know it exist), so asked directly the person that gave the idea in the first place if he had some knowledge of such e-paper screen.

I meant the assembly of the keyboard would be easier, not the whole system, as I pointed out every thing that would still be to solve... Don't know how I could have said it better....

On the other hand, you could have pointed me to things that would actually help to solve this, or explain why it would not be a good solution, but hey... :(

Re: Ideal keyboard design and configuration
 

That's the easy part !
The main difficulty is how to add a transparent layer on a touchscreen, without having false detection, keeping multitouch, and controlling the feeling of the key push...:confused:

Re: Ideal keyboard design and configuration
 

Do it physically. If the physical keys don't touch the touchscreen at all until they are pressed, there is nothing to falsely detect. If the support for the physical keys is non-capacitive, there will never be anything for the touch-surface to detect until a key is actually pressed.

The feel of the key push is also completely an aspect of the physical shape and materials of the keyboard.

Re: Ideal keyboard design and configuration
 

Yes, the key-clicking action is important, but so is the shape of the keys. For optimum text entry, one of the most important features is: you should feel with your fingertips where are the key tops (the centers of the keys) prior to pressing the key. Even if a virtual keyboard had a good haptic feedback, it is not enough. Quite similar to your dream of a keyboard seems to be the Tactus keyboad: key domes which are filled with a liquid when you activate the keyboard; see the picture on top of http://www.tactustechnology.com/technology.html Perhaps the Tactus domes don't have real "click", but it can be made with a haptic feedback component.
Tactus promised to launch a real product in 2013. Well, it would make the keyboard OH concept obsolete, if the touch features and contrast of the screen remain acceptable.

Re: Ideal keyboard design and configuration
 

Can I make a suggestion?

Start experimenting! This is getting quite specific and practical, so perhaps it is time to see whether it is possible and practical to use an e-ink display. Get a RPi, get an i2c e-ink display, get an i2c touchscreen and start materializing!

You will very soon get an idea if this is either impractical/impossible or a brilliant plan which solves all the keyboard-designing issues!

Re: Ideal keyboard design and configuration
 

I am afraid I am a pretty abstract guy, I can present suggestions and ideas, but when making things I write software. If I build anything in hardware it will at the most be an FPGA-design :) I wouldn't know where to start in buying the components and putting them together!

To build the keypad overlay in my suggestion would require someone with good materials experience to get the feel right, that is far beyond my areas of knowledge.