Human-Machine Interfaces

HUMAN-MACHINE INTERFACES

When reaching a haptic mark, the user feels a resistance generated by the motor against the turning direction.  

This force increases until a specific position is reached.  

When the knob passes that position, the force gets smaller again.  

This can be used to create the impression of a knob that can be put into a programmable number of positions.  

It allows a single knob to be used for navigating through a menu structure where each menu choice is represented by one position.

Navigation:

In order to operate applications in mobile devices, the user navigates through a menu structure, often using special navigation keys.  

An example is the integrated cursor key that delivers signals for all four directions by pressing or moving it up, down, left, or right.  

Buttons that can be operated with the thumb while holding the device are

especially suited for selecting entries from a menu list.  

These buttons can usually be turned or pressed.

Haptic Interfaces:

The programmable rotating actuator with haptic feedback is available from VDO.1  

It is basically a rotating control with force-feedback and a push button integrated into one.  

Sensors detect the position of the knob and an integrated motor produces feedback of torque when rotated.  

The way                     in which the motor responds when turning     the knob is programmable.  

Haptic marks define positions of specific feedback force changes.  

1. Keyboards

Depending on the size of the mobile device, keyboards offer either the full set of keys or a limited set of keys for data input.  

Adding a full keyboard with a typewriter layout to a mobile device inevitably makes these devices larger.  

On the other hand, limiting the number of keys will automatically make the operation of the device more complex.  

Sometimes keyboards cannot be used at all because the form factor of the device simply does not offer the space for it, or the device is used in environmental conditions where a keyboard wouldn't work.  

Therefore, some devices completely omit keyboards in favor of other input technologies, such as handwriting or voice recognition.

On Screen Keyboards

Devices with a reasonably large touch-sensitive display often make a com-promise by replacing the mechanical keyboard with a virtual on-screen keyboard.  

This does not allow touch typing but still offers a convenient method for text entry.  

Numbers and special characters can be entered after switching into another

mode, which alters the keyboard layout accordingly.  

2. Handwriting Recognition:

With the availability of sufficient processing power and touch-sensitive displays, handwriting recognition became feasible.

0 The technologies available today differ widely in the amount of processing power and input precision they require.  

1                                  Recognition of cursive handwriting is much more complex than

recognition of individually printed letters.  

3. Character Recognition:

0 Other methods limit the recognition to separated characters, and require the stylus to be lifted between letters.  

1 These technologies usually achieve a very high recognition rate but require some cooperation from the user.  

2                                  Usually there is a limited number of ways how an individual letter

has to be drawn in order to be recognized by the device.  

4. Speech Recognition:

 Speech recognition has the advantage of being the most natural input method with only a minimum of requirements in terms of space required to integrate it into mobile devices. 

 However, it is also the most expensive technology in terms of  computing power, and the most vulnerable in extreme environments.

 Recognition of continuous speech is available in computers today, and will certainly become available in mobile devices too.

 The most obvious devices for the integration of speech recognition are telephones.

 Some mobile phones already allow the selection of an entry from the address book by just speaking the name.

 In the future they will be operated entirely by voice, understand complex queries, and we may even be able to translate speech into other languages.