DESIGNING

INTERACTION

LESSON 2

ANDREA BONARINI

ARTIFICIAL INTELLIGENCE AND ROBOTICS LAB

DIPARTMENTO DI ELETTRONICA, INFORMAZIONE E BIOINGEGNERIA

POLITECNICO DI MILANO

E-MAIL: ANDREA.BONARINI@POLIMI.IT

URL:HTTP: / /WWW.DEIB.POLIMI.IT/PEOPLE/BONARINI

THE DEVICE SIDE…

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From the device side we

have to exploit the output

channels (actuators)

compatible with the human

ones, but we can classify

the input channels

(sensors) according to the

available technology

SENSORS

• They are the input communication

channel

• They are the only way to perceive signals

• They usually require some computation

to interpret the signal

• They have constraints, e.g., range of the

measured values, and operating

conditions

• They may be affected by: error,

approximation, imprecision,

discretization, ambiguity, uncertainty, …

SENSORS: DISTANCE

• Distance from the sensor

• Distance from anything (infrared, sonar, laser)

• Distance from a recognized object (camera, kinect)

SENSORS: OBJECT FEATURES

• Color

• Color sensor

• Camera

• Shape

• Fixed shape (e.g., recognition of a signal, a landmark)

• Body position (e.g., face, expression, arm position, …)

(camera or Kinect)

• Tags (ID)

• RFID, …

• Linguistic Tags

• QR-code

SENSORS: OBJECT FEATURES

• Surface

• Contact (switch)

• Kind of surface (touch sensors)

• Temperature

• T sensors

• Thermal camera

• Smell

SENSORS:

MOVEMENT AND FORCE

• Acceleration

• 3-axis accelerometer

• Camera, Kinect

• Speed

• Rotational speed (gyroscope)

• Tangential speed (camera, proprioceptive sensors)

• Force

• Fixed force (calibrated switch)

• Generic force (piezo, camera, and other sensors)

SENSORS: SOUND

• Microphone

• Amplitude

• Frequency

• Microphone array

• Beat

• Specific sound

• Rhythm

• Voice (kind, content, prosody, …)

• Sound direction

ACTUATORS

• They are the output communication

channel

• They are the only way to emit signals

• Some of them may require some

computation to generate the signal

• They have constraints (range of the

signal feature and operating

conditions)

• They may be affected by: error,

imprecision, discretization, …

ACTUATORS: MOVEMENT

• Displacement of the device

https://www.youtube.com/watch?v=HTxdKi77G20

• Moving parts (eyes, arms, …) http://www.youtube.com/watch?feature=player_embedded&v=JgGvArz1X40

• Deformating body http://youtu.be/ZOaT2A_VJ5A

ACTUATORS: SOUND

• Simple sounds (whistle, beep, …)

• Music

• Voice

Sound is produced by waving air to our ears:

the more air the more intense is the sound

ACTUATORS: LIGHT

• Simple (coloured) light

• Light patterns

• Screen

SIGNAL

CHARACTERISTICS

Most signals (I/O) have common characteristics that could be

used in interaction:

• Intensity (amplitude)

• Frequency (color, tone, pitch, …)

• Speed

• Acceleration

• Rhythm, pattern

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LET’S TRY…

14

Let’s take an object, and make it

perform an illocutionary act with a

given emotional content, selecting

a specific actuation

• A gentle order

• A urgent request

• A gentle inform

• A formal excuse

• A reassuring promise

• …

SOME BASIC

PRINCIPLES

We can adapt some basic principles of interface design to

design interaction

(I’m following here Talin 2014 - A Summary of User Interface Design Principles)

Heuristics coming from experience

Not written in the stone, but useful suggestions…

;-)

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KNOW WHO YOUR

USER IS

• What are the user's goals?

• What are the user's skills and experience?

• What are the user's needs?

But, … who’s the user?

• User models: description of user’s features

• User dichotomies (Voghera’s housewife vs. Polimi geek, …)

• Work with real users

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BORROW

BEHAVIORS…

… from systems familiar to your users

Users of innovative systems often need to refer to something

known, not just for exploiting skills, but to feel reassured

(remember the washing machine knob)

Metaphors, when selected, should be completely exploited

Possible problems:

• Poorly fitting metaphors

• Cultural differences

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FEATURE EXPOSURE

Let the user see clearly what functions and interaction

possibilities are available

"Sensables" outnumber "Intuitives“ 3 to 1

The interaction should be as clear and simple as possible,

and should not require any effort

Possible adaptation of the complexity to the user, if needed

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COHERENCE

The behavior of the device should be consistent

• Internal consistency: if some interaction is done in a way,

an analogous one shouldn’t be done in a different way, or,

possibly, it should be a clear alternative

• External consistency: the device should behave

consistently w.r.t. its environment, and expectations

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STATE

VISUALIZATION

If the device achieves different states, the relevant ones to be

communicated should be made visible to the user, possibly

without requiring too much effort (persistent signals, …)

It is even more important when an interaction is required.

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SHORTCUTS

Provide both concrete and abstract ways of getting a task done

When the user gets experience, there might be the case that

he/she no longer needs to be guided through a path to achieve

a goal, and would like to go straight to the target

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FOCUS

Some modalities attract attention more than others do…

… and it might be the case to exploit them

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INTERACTION

GRAMMAR

An interaction act has its grammatical rules and roles: action,

object, subject, adverbs, adjectives, and so on.

Moreover, the interaction modalities can be seen as ruled by

a grammar: how to make a gesture, how to provide a

sequence of information elements, ….

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HELP

There should be no need to provide help, but…

Different types of help can be needed by the user:

1. Goal-oriented: "What kinds of things can I do with this

device?“

2. Descriptive: "What is this? What does this do?“

3. Procedural: "How do I do this?“

4. Interpretive: "Why did this happen?“

5. Navigational: "Where am I?"

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SAFETY

Let the user develop confidence by providing a safety net

Each human mind has an "envelope of risk", that is to say a

minimum and maximum range of risk levels which they find

comfortable.

Adapt the interaction to both novices and experts: safety

level as an option.

However, notice that many things in life are not meant to be

easy.

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CONTEXT

Limit user activity to one well defined context unless there's

a good reason not to.

Manage possibly needed shift of contexts

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It's not necessary that each interaction and device be great works

of art, but it's important that they are not ugly.

"Never do anything that looks to someone else like a mistake."

William Rotsler

Another area of aesthetics to consider is the temporal dimension:

interaction timing makes the interface realistic and enjoyable

AESTHETICS

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USER TESTING

Recruit help in spotting the inevitable defects in your design

User testing in early stages: WoO, mockup, prototype

User testing in advanced states: real system

• Select the right set of subjects: most people have a biased

idea as to the what the "average" person is like

• Do not interfere with subjects during tests

• Describe what will happen in the trial

• Record the trial

• Analyze the records

• Obtain feedback

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HUMILITY

Listen to what ordinary people have to say

A product built entirely from customer feedback is doomed to

mediocrity, because what users want most are the features

that they cannot anticipate.

However, a single designer's intuition about what is good

and bad in an application is insufficient.

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LET’S TRY…

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Let’s design the interaction for

a washing machine

• Who’s the user?

• What interaction?

• How?

• …