Talk:Keyboard design

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Keyboard Back-light and Illumination

It seems to me that this laptop might need to work sometimes in low lighting. It would be good to possibly turn on a back-light under the keyboard. It sounds easy to have translucent rubber so the light shows through to help see keys. --imajeff 2006-04-10

Or possibly another idea for enabling users to type in the dark would be to have a on-screen guide, showing the actual keyboard layouts that they are typing on. This is all aimed at getting the users who may not have access to extensive lighting and electricity at home up-to-speed with using the keyboard layout as quickly possible, even if this is at home in the late evening.


(section as suggested in http://wiki.laptop.org/wiki/User_talk:Imajeff even though the section above on Keyboard Back-light was noticed after that suggestion was made. The thing is, I thought that "Illuminating the keyboard" is a good idea, yet I thought that it meant a light onto the keys rather than a light under translucent keys, which is also a good idea.)

Our current plan is to have a light in the bezel that can illuminate the keyboard. Walter 21:13, 4 July 2006 (EDT)

May one suggest at minimum a pair of lights in the bezel on left and right to be used with appropriate hoods to shade the eyes and direct the light towards the keyboard. Two LED sources would give a more even illumination for the keyboard with lower power than a single LED.

It is hard to position a single LED to illuminate a keyboard in a completely dark room. If one uses the screen to illuminate the keyboard one leans the screen down to direct light on the keyboard to read key caps and then the screen gets in the way of the hands and is too low an angle to read.

May one suggest that the keyboard colors be optimized for night time operation. In the daytime it takes less black ink to make black letters on white paper. At night it takes less light to back light translucent white letters on black background. On the other hand, if the back light is running under the whole keyboard -- both the black part of the key caps and the translucent part of the key caps -- then making the keyboard translucent background with black marks would let more light out.

One may mention that some newer automotive speedometers change between white letters on black background and black letters on white background depending on ambient light. These speedometers are hard to read at twilight. So, if back lighting is used, the colors of the keyboard should remain the same whether or not back lighting is turned on.

Special geometry of thin sheets of clear plastic with frosted front can allow side light to illuminate. This is done behind LCD screens where a fluorescent tube smaller in diameter than a pencil illuminates the entire screen. The reverse is done by particle physicists who use special shapes of lucite to direct photons of light from experiments into photomultiplier detectors. Similar special shapes of clear plastic could back light the keyboard with a few LEDs for side lighting. It would add a few mm of thickness. --2007-03-11

Keyboard layouts and requirements of keys

Currently, there are keyboard layouts in Xorg that require a right Alt key (the AltGr one). These keyboard layouts define characters when you press AltGr and a letter. With only one Alt key this would need some rethinking.

In addition, Xorg (XKB) allows to use a Compose key (Multi Key) to enter special characters. If you use GNOME, enable the Compose key in order to write extra Unicode characters. Usually, users set the Win key to be this Compose key. On the OLPC, will there be a spare key that can have the role of the Compose key?

With the compose key you can create universal keyboard sequences and type interesting characters such as ☗☻☎☪♜⚈⚉⚖⚄⚅♥♦♣☻☭☬. For example, you can make a sequence that the child types Compose : - ) and gets ☻. It's much better than using bitmap images. --Simosx 15:08, 10 July 2006 (EDT)

Might one ask if the PC function generating a character by pressing down the alt key and typing a three digit sequence on the numeric keypad and then releasing the alt key will be replaced by something that can enter unicode characters?

May one ask for clarification of the use of the word compose? When one prints on paper or on a graphics display there is the possibility of overstrike where multiple glyphs are placed on top of one another. To some minds this is what one thinks when one hears the word compose. Unicode has letters with built in accents and letters to which separate accent characters may be superimposed. --2007-03-11

Alternate keyboarding

To leave off the standard keyboard for the first version would be foolish but...

At present, on either side of the monitor are two dual-axis controllers (joysticks). I believe that there are some buttons on the back as well. Essentially, two joysticks with four buttons (this configuration is similar to a certain popular game controller).

If the two joysticks had some directional feedback; then each of them could act as an eight valued selector. 8 * 8 = 64 combinations/changes (think the I-Ching trigrams/hexigrams). Using one of the buttons as a mode selector, another button could be recruited as shift key and another as a number key. This covers the standard 256 character ascii set very handily. This technique has appeared in some products (http://www.keybowl.com/kb/index?page=home).

If this alternate character entry mechanism were to become popular, think about how much simpler (i.e. more reliable) the hardware becomes.

  • no hinge or at least one that doesn't contain electronics
  • no keyboard with its many modes of failure

In the meantime, the additional way to generate characters would be a fall-back should the keyboard fail.

Why do I think this might work? Children are not pretaught to type on a keyboard. Children are already familiar with game controllers (especially if the game makers could be convinced to use the same encoding).

May one suggest that whatever could be considered for alternate keyboards must work with motherboard bios (if any is needed before starting the operating system). One has observed that some operating systems must load drivers to work with USB keyboards and the USB keyboard will not work before the operating system has started. We have approximately 25 years of experience with the IBM PC and IBM AT keyboards interacting with mother board BIOS. Might one ask if there is a separate standard for keyboard requirements without the operating system and keyboard requirements after operating system has started. Linux uses kernel modules to talk to different hardware so unless the mother board BIOS can load a special keyboard kernel module the whatever-keyboard must be able to send what the motherboard needs to set up before booting or to replace a non working configuration and operating system with a working one.

May one add that it was reported that alphabetical order in a hand held terminal was faster than qwerty for persons who are not touch typists. Just like when one is holding a calculator or cell phone one hand holds the unit and the other hand is used to press keys. If the device is small enough a thumb of the hand holding the unit can get to all of the keys on the front. Placing keys in alphabetical order will reinforce alphabetical order but it gives away the answer to show the letters of the alphabet in alphabetical order. English speaking children sing this song in kindergarten before they learn the shapes of the letters so revealing alphabetical order on a keyboard with permanent marking might not matter.

Standardized game controllers might be nice but whose specification? May one suggest that unless manufacturers are forced to meet a standard there is a business tendency to make everything different and to keep changing things so parts can only come from the original manufacturer. IBM computers that used EBCDIC character encoding had a bit to switch the CPU to ASCII to meet a government bid requirement but the operating system and printers ran on EBCIDC Try to change an automobile door handle between automobiles from different manufacturers. Chip sets in commercial products change without notice. The linux device driver writers are often not given specifications and might not know that there are multiple chip set versions until some user discovers a different chip set that does not work with a driver. -2007-03-11

Fluroscence Keyboard

What if keyboard keys are like fluorescents, then only the light from screen could easily make them visible in dark and it would be lot more easier to type in dark, I think this will reduce the need of keyboard illuminating LEDs(though they have other significance too, for eg. simple light at place where there is no source of electricity.). But I doubt whether it is environment friendly or cost effective to have such kind of keyboard.

Physical dimensions of key caps and gaps between

Might one ask if the size of key caps and size of gap between key caps is considered so that the keyboard may be used by hands of teachers in addition to smaller children. May I direct your attention to two keyboards that have been around for over 50 years: the piano and the telephone touch tone keypad. Both of these keyboards meet a requirement that one finger can press a single key without pressing adjacent keys. If the keyboard is made smaller to fit hands of smaller children and if the keyboard must also be used by adult fingers instead of an upside down pencil eraser then the gap between keys needs to get larger and key caps need to get smaller when key caps get closer together.

One may also need additional gap between key caps if the laptop is to be operated in colder climates without home or classroom central heating. Finger dexterity drops off below about 10 deg C. When one wears gloves the glove bumps adjacent key caps. The gaps between numbers on the original touch tone keypad are wide enough to allow an adult wearing gloves to press a single key.

Sloping sides of the key caps helps when the tips of fingers are rounded but does not help if the tips of fingers are more squared off as adult fingers are.

Minimum size of a key cap is limited by the need to place three symbols on the key cap. One may not expect every child to have perfect vision and one would not want not want to exclude a child with poor vision so key caps must be large enough to contain the symbols. Additional limits on size of top of key cap are due to thickness of the rubber that connects the top of the key cap to the bottom of the keyboard and by the minimum size of the electrical contact and spring mechanism that returns the key cap to upright position when the finger is removed.

A further reason for making the gap between keys on a reduced size keyboard wide enough for an adult hand is to promote adult literacy when children take the laptop home. --2007-03-11

Permanent marking on key caps

One has seen a five year design life mentioned in the specifications. Laptop keyboards are built in. It may be necessary to make the keyboard a field replacement without soldering. Meaning another connection that could fail.

There are several common ways to mark key caps made from hard plastic: hot stamp, paint, and double shot. The hot stamp method uses thermal transfer from a ribbon. Hot stamp is not very thick and it eventually wears off. Paint applied by silk screening is not very thick and it eventually wears off. Double shot in injection molding in rigid plastic does not wear off because the thickness of the marking is as deep as a US dime coin. Can and will the rubber keyboards be made with double shot injection? --2007-03-11

Missing keys

Might one ask about the rationale for each of the list of buttons and keys that are omitted. Why two mouse buttons rather than three? Is there a cost difference? I know of a few IBM and Compaq that have three mouse buttons and have seen laptops with both pointing stick between g and h key caps and touch pad.

Is there enough room inside the laptop to add a pointing stick that comes up through the rubberized keyboard? Might one design the keyboard to allow for a an unused space free of any wiring between the g, h, and b key caps as a place for a future cutout in the rubberized keyboard to let a pointing stick come up from beneath?

Might one have a third mouse button without extra cost? What does one do when some software says press the left and middle mouse button at the same time or press the middle and right button at the same time. Chord emulation on a two button mouse does not do this very well.

One who has become used to having the six key rectangle: insert, home page-up, delete, end, and page-down will miss these.

The cursor up, left, down, right arrangement is good. It was used as early as the IBM PC-junior. --2007-03-11

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