Some examples of Bad design
Example 1
• For the bell to ring, the ti
mer must be turned to
greater than 15 minutes,
and then set to the
appropriate time
• Not very Intuitive!!!
• Both sides of the
refrigerator are
identical
•There is no handle on
the front
• How do you open the
fridge
Imperceptible!!!
• What is this sign
telling motorists to
do?
• Check out
• http://www.baddesigns.com/examples.html
Difficulties using Every Day
Products
Estimated Numbers with Functional
Difficulty in the UK
• Dexterity – 1.7 Million
• Reaching and Stretching – 1.2 Million
• Manipulating and Gripping- 0.3 Million
• Lifting and Transporting – 0.6 Million
Difficulties with Everyday Products
Difficulties with Kettles
• Manipulation and gripping 273,000
• Lifting and transporting 615,000
Manipulation
The order of difficulty of packaging products
(1 being the easiest) is shown in the table
below:
• 1 Cleaning solution • 11 Tea bag
• 2 Washing up liquid • 12 Instant soup
• 3 Soup tin packaging
• 4 Sugar • 13 Meat tin
• 5 Washing powder/liquid • 14 Plastic bottle
• 6 Tin of tuna • 15 Toothpaste
• 7 Butter • 16 Cereal packaging
• 8 Milk • 17 Cheese packaging
• 9 Microwave meal • 18 Jam jar
packaging • 19 Shoe polish tin
• 10 Bread packaging
Gripping
• 1 Cleaning solution • 10 Butter
• 2 Microwave meal • 11 Tea bag
packaging • 12 Tin of tuna
• 3 Instant soup packaging • 13 Plastic bottle
• 4 Soup tin • 14 Cheese packaging
• 5 Washing powder/liquid • 15 Meat tin
• 6 Sugar • 16 Toothpaste
• 7 Milk • 17 Shoe polish
• 8 Washing up liquid • 18 Cereal packaging
• 9 Bread packaging • 19 Jam jar
Lifting
• 1 Shoe polish • 12 Jam jar
• 2 Tin of tuna • 13 Toothpaste
• 3 Tea bag • 14 Cereal packaging
• 4 Instant soup packaging • 15 Soup tin
• 5 Meat tin • 16 Washing powder/liquid
• 6 Cleaning solution • 17 Sugar
• 7 Butter • 18 Microwave meal
• 8 Bread packaging packaging
• 9 Cheese packaging • 19 Washing
• 10 Plastic bottle
• 11 Milk
Transporting
• Packaging products - transporting
• Products excluded from the list because of small sample numbers include;
• • No excluded products
• 34
• 1 Cleaning solution
• 2 Tea bag
• 3 Instant soup packaging
• 4 Toothpaste
• 5 Milk
• 6 Bread packaging
• 7 Cereal packaging
• 8 Plastic bottle
• 9 Tin of tuna
• 10 Jam jar
• 11 Butter
• 12 Washing powder/liquid
• 13 Microwave meal packaging
• 14 Sugar
• 15 Washing up liquid
Capacity Demands
(Capability Demands Clarkson)
• Looking at the above milk bottle designs:
• Each bottle design demands that the user has a
capacity to perform a vertical lift by gripping the
handle with a closed fist grasp.
We see that the bottles on the left will allow a
greater range of hand sizes get a proper grip on
the handle for lifting since it gives greater
clearance dimension between handle and jug
• In other words the structure of each bottle
implies the user must have particular hand
dimensions in order to manipulate the bottle
• Thus each bottle places different demands on
the user attributes.
• If these demands are not met then the bottle
cannot be used.
• This conflict is the essence of how capacity
demands define the guards of our petri nets
• The above is an example of an object
capacity demand.
• There are other kinds of capacity demands
based around action
• These must be measured against the
personal capacities of the agent and the
attributes of the environment
• This is summarised in the following
Capacity
Agent Demands
Capacities, Action
Environmental
and
Factors,
State Objects
Attributes
More formally
Transition Guard representing
Barriers
Incoming Tokens representing
( in terms of Capability
Person and State
Demands)
Action
State Capability
Demands
Person
Capability
Object
Tokens
Capability
Demands
Environment
Attribute
Tokens Environmental
Demands
Capacity Demands And Assistive
Technology
• Action and objects place capacity demands on people
and environment.
• For example using a standard kettle involves a capacity
demand of being able to perform a vertical lift of up to 1
kg(which is the weight of the kettle when full with water),
one handed using a closed fist grip.
• Assistive Technology changes the relation between
personal and environmental capacities and the capacity
demands of the action being executed.
• This relationship is represented by the guard of the CPN
• This is shown in the following example