Design Of Controls Flashcards
For a control that is activated by a small actuation force and has a small range of continuous settings, what type of controls should be used? For a control that is activated by a large actuation force and has 2 discrete settings, what type of controls should be used?
Small force, small continuous range:
knob/joystick lever
Large force, 2 settings:
Hand pushbutton/ foot pedal
What 2 things should a control be?
Appropriate and intuitive to use
Over the years, many controls have become standardized. Provide 3 examples of this.
Car controls incl. gas, brake, steering controls
Manual lever for aircraft throttle
Lever control for gear shift
Provide 3 advantages and 3 disadvantage of using either touch screen or light pens as computer input devices.
Advantages:
- Little training. Pointing is intuitive
- Good for public environments
- No moving parts. Robust and sturdy
- Excellent hand-eye coordination
Disadvantages
- Maintaining arm extension could induce fatigue
- Input resolution poor
- Pointing object partially obscures display
What is ‘negative transfer of training?’
When a user operates according to previous training with a new or different control scheme, resulting in error
What is “control movement stereotypes”? Provide 3 examples. What are the consequences of designing controls that contradicts such stereotypes?
Control Sterotypes are learned behaviours, ideas that controls should behave in certain stereotypical ways. Example: tap to the left for hot water. Turn a knob away from the door jamb to open it, light swithc up to turn it on (in US).
If you don’t follow these you might encounter user errors, which may lead to a product not selling, or people dying
What is a “one-to-one” correspondence? Provide an example of a “one-to-one” correspondence and a non “one-to-one” correspondence.
1-to-1 correspondence is when the motion of an element matches the motion of the control. This is highly desirable. Example: Light dimmer switch. Brightness up= slide dimmer up
Example of not 1 to 1: Push lever FORWARD in forklift, and the lifting beams go DOWN
What is control response compatibility? What are the 5 levels of compatibility? Give a sentence or example to describe/explain each.
• Compatibility refers to the relationship of stimuli and responses that are consistent with human expectations, resulting in decreased errors and faster response time.
Levels:
Conceptual- Is the code meaningful?
Affordance- Perceived property results in the desired action. Alternatively: a control lends itself to the function it performs
Movement- Relation btwn control movement and element movement
Spatial mapping- Physical arrangement of controls and display
Modality- Using same stimulus modality for signal and response
Which of the compatibility level does the typical stove top we have in our kitchen violate? How would you redesign the stove top to avoid this incompatibility?
Spatial Mapping.
Arrange the controls in a square matching the burner arrangement
Provide an example for each mode of control coding
Location– turn signal beside steering wheel
Color–Red=danger
Size– Allows distinction when not visible e.g. Making master power button small on laptop-> minimize accidental shutdown
Shape– Making different lever handles diff shapes to be distinguishable without looking. **INCL surface texture
Labelling– “ Push to start”
label explicitly says what control does. Keep design pros in mind. Readability and ease of understanding.
Mode Of Operation– Nature of control (button vs lever etc) or the resistance level btwn similar controls distinguishes btwn them
What are the 6 types of control coding?
Code By:
- Location
- Color
- Size
- Shape
- Labeling
- Mode of Operation
Why is it important to consider illumination level and color stereotypes when coding by color?
Illumination affects color and thus code visibility
Stereotypes can influence an operator to act contrary to training, or make training harder to instill
If there is a set of controls that you need to activate, but you cannot see it because it is hidden in back of machine, what are 3 ways to code the controls so you will not make a mistake when using it?
Code by size, shape, and Mode of operation
Explain and provide an example of why it is important to maintain consistency when coding controls.
To avoid accidents caused by negative transfer of training
What is redundant coding? Why/when should redundant coding be used?
Redundancy is combining different dimension of control coding even though one may theoretically suffice. Best used for emergency controls to minimize mistakes/ ensure control is recognized. When designing redundancy, multiple modalities are more effective than multiple dimensions within the same modality
