Input devices Flashcards
Types of sensing methods to classify computer input
Mechanical
Motion
Contact
Signal processing
Degrees of Freedom
Number of independent motions that are allowed to the body
What are perceived problems are there with qwerty
Common combinations require awkward finger motions (eg: tr)
Common combinations require a jump over home row (eg: br)
Common combinations are type with one hand(eg: was, were)
Most typing involves the left hand
DVORK vs QWERTY
No significant difference as some studies suggest DVORAK is faster while other suggest the opposite
How are keyboards adjusted to to make device portable
Keyboards downsized, or made in different shapes. Leads to difficulty typing
Pros of virtual keyboards
Portable
Customizable keys
Customizable layout or functionality
Cons of virtual keyboards
Small keys reduce accuracy
No mechanical feedback makes it hard to tell if key was pressed
No tactile feedback makes it hard to find home row
resting of hands difficult
Other types of text recognition and gestures
Graffiti/Unistroke gestures
Natural handwriting recognition
Predictive Text
Uses languages characteristics to predict input
Possible problems with predictive text
“Collisions” between common words
Entering words in dictionary difficult
Hard to focus on typing and prediction
Types of predictive text system
Apple QuickType
Google Gboard
Typewise
Text input WPM
QWERTY: 60
T9 (Predictive): 45
Handwriting: 33
Absolute vs Relative position
Absolute: 1-1 direct mapping of input device position to display input position
Relative: Changes input device position to changes in display input position
Clutching
Technique that allows user to reposition mouse and continue moving
Direct vs Indirect input
Indirect: Position of the cursor controlled by some external devices (controller)
Direct: Position of cursor is controlled by direct contact with the screen (touchscreen)
Occlusion
Issues when finger covers object of interest. Likely contributes to errors, fatigue, inefficient movements and impedes performance
Adv of speech input
Requires limited training
Best when hands/eyes are occupied
Disadv of speech input
Feedback may be limited
Speech is a single channel mode
Not appropriate for use in open or noisy environments
Gestural input pros
Gestures map movements to commands
Immediate and powerful interaction
Disadv of gestural interaction
Discoverability (Not self revealing)
Memorability (Recall over recognition)
Fatigue (Movements over period of time can be very exhausting)
Gesture recognition accuracy
