MEC 325 Chapter Notes - Chapter 6: Rotary Dial, Steering Wheel, Touchscreen
3 May 2018
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Chapter 6
Design of controls, displays and symbols
-Appropriateness of manual controls- appropriate to task and intuitive to use
classified by the number of settings and by the force required to manipulate the control.
6.3 STANDARIZATION OF CONTROLS
- ie. Cars;
• Steering wheel for steering
• Joystick for airplanes
• Foot pedals for braking and acceleration
• Manual lever for aircraft throttle
• Lever control for gear shift
- Changes from before HF to after HF- ie. Pushbutten telephones to rotary dial telephones
– reduce errors/less costly
-
With the emergence of computers, many control functions have become less visible
(like the water tap in the train), and as a result they are more abstract.
two problems: the selection of an input device and the
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design of the graphical representation of the control process.
--- For touch screens and light pens, one has to point with a finger or a stylus;
this provides excellent hand-eye coordination. Pointing is a very direct way of expressing
preference. The pointing finger will partly obscure the view of the display, and the input
resolution is poo
.
Systems that used to be controlled manually are controlled remotely by a computer.
The control action as well as the system response can now be represented graphically on a
computer screen
Touch screens are particularly appropriate for use in public environments, such as
information displays at train stations and ticket vending machines at airports. This type of
device has no moving parts, and it is sturdy and robust.
The mouse, the track-ball, and the joystick have the best input resolution; therefore
they are the best for accurate pointing.
Touch screen- muscle fatigue
The best device would
be the one that requires the least time and produces the least number of errors in
performing the task.
- coding of controls
- control movement stereotypes (vary by culture
- ie. Light switch, up-on-> U.s, up-off, Europe
- klearned from childhood
- crane- move vertically, control moves vertically upwards-> vertical control, pull lever
back
TABLE 6.3 Control Movement Stereotypes:
Common Expectations for Control Activation
Controlled Element Human Control Action
On= Up, right, forward, clockwise
Off =Down, left, backward
Right= Clockwise, right
Raise= Up, back
Lower =Down, forward
Retract =Up, backward, pull
Extend= Down, forward, push
Increase= Forward, up, right, clockwise
Decrease= Backward, down, left, counterclockwise
Open valve= Counterclockwise
Close valve Clockwise= CW
The control movement is horizontal, but the controlled
element moves vertically. Many individuals would make a mistake by pushing the
control forwards (unless they have been thoroughly trained).
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Document Summary
Appropriateness of manual controls- appropriate to task and intuitive to use classified by the number of settings and by the force required to manipulate the control. Ie. cars: steering wheel for steering, joystick for airplanes, foot pedals for braking and acceleration, manual lever for aircraft throttle, lever control for gear shift. Changes from before hf to after hf- ie. pushbutten telephones to rotary dial telephones. -- for touch screens and light pens, one has to point with a finger or a stylus; this provides excellent hand-eye coordination. Pointing is a very direct way of expressing preference. The pointing finger will partly obscure the view of the display, and the input resolution is poo. Systems that used to be controlled manually are controlled remotely by a computer. The control action as well as the system response can now be represented graphically on a computer screen.
