Prototyping tangibles : exploring form and interaction

Prototyping tangibles : exploring form and interaction
PETRELLI, Daniela, DULAKE, Nick, MARSHALL, Mark, WILLOX, Matt,
CAPARRELLI, Fabio and GOLDBERG, Robin
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PETRELLI, Daniela, DULAKE, Nick, MARSHALL, Mark, WILLOX, Matt,
CAPARRELLI, Fabio and GOLDBERG, Robin (2014). Prototyping tangibles :
exploring form and interaction. In: TEI '14 : Proceedings of the 8th International
Conference on Tangible, Embedded and Embodied Interaction. ACM, 41-48.
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Prototyping Tangibles: Exploring Form and Interaction
Daniela Petrelli, Nick Dulake, Mark
Marshall, Matt Willox, Fabio Caparrelli
Sheffield Hallam University
153 Arundel Street, Sheffiled S1 2NU - UK
[email protected]
ABSTRACT
In order to better explore the opportunities for tangible
interaction in new areas such as the home or cultural
heritage sites, we used multiple rapidly-developed
prototypes that take advantage of existing technology.
Physical prototypes allow us to give form to ideas and to
evaluate the integration of form and function, two core
components of tangible interaction. We discuss potentials
and pitfalls when using off-the-shelf digital devices (by
embedding a device, cracking it open and building on it, or
collating board and parts) through six prototypes developed
in two studies. Hacking devices to materialize our ideas
proved excellent for fast prototyping. Technology imposed
constraints and prompted different design solutions than
initially intended offering unexpected ways to engage. On
the basis of this experience we outline a process and offer
guidelines for the fast prototyping of tangible interactions.
Author Keywords
Tangible interaction; fast prototyping; user feedback.
ACM Classification Keywords
D.2.1 Elicitation methods; H.5.2 User Interfaces.
INTRODUCTION
Material objects and their form are important in tangible
interaction [1, 10]. A known form can afford specific
behaviours and interaction designers can take advantage of
this when creating new tangibles. The critical point is how
integrated form and function are [1, 9], as loose connections
and arbitrary mappings can mislead users [9]. The potential
and pitfall of the form factor are well known in industrial
design and prototypes are regularly used to systematically
explore different forms and details. The understanding of
how the prototype will fit in its context of use progressively
grows through this iterative cycle of making and evaluating.
This view of prototypes as tools for thinking and learning is
shared across disciplines as diverse as product/service
design [3] and software development [6]. How the
prototypes look and function depends on which aspect of
TEI’14, February 16–19, 2014, Munich, Germany.
Robin Goldberg
Institute for Visualization and Interactive Systems
University of Stuttgart
Pfaffenwaldring 5a, 70560 Stuttgart, Germany
[email protected]
the final product they mean to capture and the current stage
in the design/development process [6, 8, 12]. Sketches,
paper mockups and other forms for communication, such as
video prototypes are extensively used in the early stages,
but once past the brainstorming phase quickly built “throwaway prototypes” are less common.
This paper discusses the value of physical prototypes as a
means to explore new domains for tangibles. Physical
prototypes enable designers to focus on form and function
simultaneously and how the two integrate. However to be
able to quickly try out many ideas the cost of prototyping
(in both resources and time) must be low. In six examples
from two different case studies we show how costs can be
reduced by using consumer devices and off-the-shelf
technology (such as sound recording and playback devices)
to provide core functionalities. This approach allows us to
take the function for granted and concentrate on the form
factor. 3D printing and laser cutting are used to shape forms
closer to the final product than those achievable with
cardboard and therefore enable us to fully explore at an
early stage how potential adopters would interact.
We first review prototyping in design and software
development and discuss the advantages of using existing
technology. The two case studies then show three types of
prototype: embedding devices, cracking them open, and
collating components. We conclude the paper reflecting on
the process we followed and providing guidelines for a
hands-on trial.
PROTOTYPING IN DESIGN AND COMPUTING
Prototyping is not a new idea. In computing prototyping has
been discussed since the early 80s [6] and physical
prototyping is as much a core part of traditional industrial
design as it is of the newest service design [3]. There are
many forms of prototypes. Floyd [6] lists exploratory
prototypes (informal, offers alternatives, unstructured and
messy, used to communicate, to be thrown away);
experimental prototypes (a proposed solution to a problem);
evolutionary prototypes (appear later in the development
and is a nearly-complete system). Hounde and Hill [12]
distinguish prototypes on the basis of what they capture and
therefore what they can evaluate (implementation, role or
look-and-feel); early prototypes focus on one aspect while
later prototypes should integrate the three. Design [3, 14]
shifts the attention from the product to the experience thus
encompassing, beyond the person and the object/system,
the context of use and factors like fun and pleasure. For
Brown [3] prototypes are not working models: their purpose
is to give form to an idea, show its strengths and
weaknesses and identify new directions. They must be
created quickly so as not to interrupt the creative flow, and
should feed back immediately for a new round of reflection
and design. Despite their diverse approaches, all authors
agree that prototypes facilitate communication across
different disciplines and with users. They materialize tacit
knowledge [14], clear possible misunderstandings [6], and
show how the work progresses [3].
Research to understand prototyping in pervasive computing
and tangible interaction is limited. Hartmann et al. [8]
looked at hardware and software mashups in professionals
and amateurs with the first group making use of existing
technology to explore new ideas while for the second group
it was a mean to go beyond their actual competence.
Professionals aim to try ideas quickly, postponing aspects
of efficiency, and see this work as disposable. Similar
findings are in Brandt et al. [1]: opportunistic programmers
used cut-and-past code techniques as a method for fast
prototyping. The value is not in the code produced, but in
the knowledge gained during the process.
More effort has been spent in developing toolkits for
prototyping: to map functions to specific sensors [7], the
hardware of a new device to a 3D form [18], to integrate
form and interaction “in rough form” [13] or as simulation
[11]. All these examples, however, tend to overlook the
value of aesthetic: form, when considered [11, 13], is a
cardboard and duck-tape mockup. Also, the use of a toolkit
may constrain the creative thinking to what the toolkit itself
allows us to build or to what the designer is able to do with
it. With our approach we stay open to any form and any
interaction and take advantage of existing technology in
speeding up the process of prototyping tangibles.
WHY USING OFF-THE-SHELF TECHNOLOGY?
The most striking advantage offered by using exiting
technology for prototyping is the small scale and light
weight. People are used to powerful devices that fit in one’s
hand, but any attempt to build in such a small scale in the
lab is destined to fail. Large-scale production takes
advantage of optimized chip design and printing, the cost of
which cannot be justified for just a few exemplars.
Second is robustness: devices made for the consumer
market have to work reliably over time. To know that the
technology will work robustly is an invaluable advantage
for interaction designers who can concentrate on exploring
and understanding how the integration of form and function
affects interaction.
Limited creation cost is also of great advantage: buying offthe-shelf devices or dedicated small boards is cheap and
saves much soldering time. This allows the creation of
exemplars that can be given away to potential users for full
appropriation, as in (Fig. 2). It also provides some sense of
the final cost, should the prototype become a product.
A further advantage arises in relation to expertise. Clearly,
electronics knowledge is essential for creating new
hardware but many of the prototypes discussed in this paper
did not require any. The knowledge needed was of 3D
modelling and printing/laser-cutting, activities that are
becoming familiar to contemporary DIY enthusiasts.
Last but surely not least is the very limited time needed to
make a prototype. For example the whole process, from
conception to devices selection, 3D modelling and printing
the cases, composing and finish, took less than a week for
the digital baubles developed in our first case study (Fig. 1)
or the birdhouse in the second (Fig. 5).
Time, cost and expertise are fundamental factors for fast
prototyping. The possibility to quickly give shape to one’s
ideas and try out many options during multiple iterations is
an exciting perspective for designers who think with their
hands and understand through making [3].
THREE TYPES OF FAST PROTOTYPES
Two case studies each with three prototypes created using
existing devices or components (as opposed to bespoke
ones) are used to illustrate our argument. While the first
case study was used to lay the foundations of the process,
the second validated it in a substantially different context.
Using the same three types of hacked prototypes in a
different project reinforced the feasibility of the chosen
categories. In this section we outline the three types of
prototype, before discussing the case studies themselves.
Embedding
Embedding a device involves inserting the entire device
into a new form factor. By simply changing its context and
shape, a device can gain a new interactive, tangible quality
while preserving its basic functionality. The main challenge
here is to map the controls to provide meaningful
interactions, which requires little or no knowledge about the
underlying technology.
Cracking it open
Sometimes the right technology is just hidden in another
case or form. Taking it out of this case and using only the
necessary parts in a new context enables fast prototype
creation without the need for deeper technical
understanding. Thus we create a new device by using some
internal parts of an existing one.
Collating
Using multiple devices and combining the abilities of
different technologies requires technical knowledge but
allows us to test various scenarios without expensive,
specialised hardware and keeps the design flexible for
possible future modifications. Collating involves combining
a number of existing technologies or devices to create a
single more complex prototype. Some limited coding can
also be done in order to create the desired interaction. This
is likely to be based on reusing or modifying existing
libraries or code that is available online. New code is
written only as required by the design process.
Figure 1: A pocket-size digital photo frame is embedded in a photo bauble.
CASE STUDY 1: DIGITAL CHRISTMAS MEMORIES
Our first case study was in the context of digital Christmas
memories bound to physical, interactive objects [8]. This
was a new territory that we explored through prototypes.
Embedding
What was the design concept?
Our aim was to create digital baubles that captured and held
personal media, such as a set of precious photos or the
sound of past Christmas. They had to be small (hand size),
extremely simple to use, easy to pass around and,
ultimately, fun. The initial concept was of a bauble locked
up until the ‘right time’ arrived to access the recorded
content. The bauble indicated that the opening time was
approaching by progressively increasing its glow day after
day and unlocking only on the predefined date.
How did the prototype capture the concept?
When reflecting on the core features we intended to
explore, it occurred to us that there were actually two of
them: encasing personal content into objects and using the
passing of time to create anticipation. This generated
distinct prototypes, discussed along with other digital
Christmas concepts in [15]. The image bauble concept
encompassed capturing and playing. We spent some time
thinking how we could have both but decided to start with
the easiest (playing) and to discuss ‘capturing’ during the
workshop with potential adopters. This directed our choice
of device: photo cameras were expensive and needed more
time and engineering expertise to hack; a digital photo
frame offered the needed functionality (display personal
content), while being low cost and ready to use (Fig. 1b).
As mentioned above, the pocket-sized photo frame spurred
creativity. The small size of the screen, excellent for
embedding into small objects, triggered the idea of using
the magnifying property of a viewfinder. We loaded the
photo frames with photos captured by the workshop
participants during the field study carried out the previous
Christmas [15]. This was essential for the participants to
engage with the prototype at a deeper level.
What was learned from the prototype?
In the workshop, the bauble was displayed as part of a
composition (Fig. 1c) and blended nicely with the
environment as opposed to appearing to be an unfamiliar
digital device. The participants engaged with the bauble and
commented loudly on what they were looking at that no one
else could see: there was much passing back and forth
between members of the same family when trying to
identify the person in the picture. The photo frame’s play
mode was set on automatic and this provoked much
discussion on how to control the pace of display via natural
gestures such as shaking. The bauble was also switched on
before the workshop started so by the time we discussed it
the battery had run out and we had to recharge it (through a
USB cable connected to a PC) before we could proceed.
This hiccup prompted a discussion on how to charge these
devices, with options such as a pull cord or solar cell.
Cracking it open
Motivated by the feedback from the workshop, we made
another digital bauble to be deployed at Christmas (Fig. 2).
What was the design concept?
We focused on sound as it was easier to find a device that
records and plays sound rather than images. Also, even
more than images, sound captures the feeling of the
moment and prompts reminiscing in a deeper emotional
way [5] as by this enthusiastic comment on a mock-up
sound bauble (Fig. 1d): “I love that – that would be such a
family heirloom”.
How did the prototype capture the concept?
A dictaphone provided all the functions for this prototype.
As soon as we received it, we realised that we would have
to design the interaction around the dictaphone's control
buttons and their positions. For instance, the delete button
was located on the side of the device whereas the play, stop,
record, forward and backward buttons were on the front.
We then dropped the delete command to see how this
affected its use during deployment.
We intentionally avoided using the screen of the dictaphone
to emphasise the “opacity” of sound. The dictaphone also
used a method of navigating through the recorded sounds
that we did not like and did not want to incorporate into our
prototype. Time was spent determining how to work around
the constraints posed by the device, together with the best
set of controls and how they fitted in a layout we liked. In
the end the prototype had just four buttons (Fig. 2): play,
stop, record, and next sound.
Figure 2: A Dictaphone provided the functionalities of a sound bauble. Mapping the buttons on the device required some thought.
What was learned through the prototype?
Sound baubles were given to five families for Christmas.
To foster appropriation, they were delivered without any
decoration but as a DIY toolkit (Fig. 2d). A one-page
manual was included to explain the controls of the bauble.
Feedback from users was rich and varied. What is
particularly interesting here is the reaction to the lack of a
‘delete’ function and the navigation through sounds being
limited to ‘next’. Finding “the nice sound I know is there”
from among hundreds snippets proved difficult with
navigation limited to just the 'next' control. The missing
‘delete’ function pushed a family to carefully plan what to
record as they did not want to end up with many
meaningless recordings. Similar comments were made by
the families with small children who made many identical
recordings. Many sound pranks occurred in the family with
teenagers, whose parents were anxious to erase them.
Making the ‘delete’ function available but difficult to
access is worth exploring, as the pranks could feel different
in a few years, when seen from a nostalgic point of view.
Collating
What was the design concept?
Much insight was gained through the previous prototypes
and we wanted to capture some of the new ideas that these
prototypes inspired: to split the record and play functions
and to make the recording component small enough to be
taken anywhere but limited to just one sound clip. In this
case we decided that playback would occur on a different
device where multiple recording cartridges could be docked
and played in sequence (Fig. 3a). The cartridges can be
personalized. This supports locating a specific recording, as
it makes the mapping between the cartridge and the sound it
contains explicit. The order of play can be changed each
time by simply shuffling the cartridges.
How did the prototype capture the concept?
The core element of this concept is the separation of
recording and playback functions. For this we needed to
lower our level of hacked prototyping and use an off-theshelf sound-recording board. We also used this opportunity
to try out autonomously powering the device through solar
cells. As in the previous cases, we had to work around
constraints of the chosen device and this stimulated our
creativity. In particular, the prototype must be set by the
user to either play or record mode; this setting determines
the outcome of the subsequent command. In the prototype
the sound-board is set to play by default and switching
between the two modes is triggered by placing a magnet on
the cartridge to enable recording.
What was learned through the prototype?
This prototype highlighted the issue of quality as the sound
from the board was too poor and not acceptable for
deployment. The form as well was a dead end: to
accommodate the solar panel a square shape was forced in a
design that was intended to be a more graceful round shape.
However the making of the cartridges increased our
understanding of ‘pocket-memories’ and opened up new
interaction options, such as encasing the magnet on a
necklace that must be placed on the cartridge to record.
CASE STUDY 2: INTERACTIVE CEMETERY
The second case study explored concepts in an historical
cemetery as part of the meSch project [16]. While for the
Christmas study the prototypes were sequential, each
stemming from previous findings, here we explored
concepts in parallel broadening our experimentation with
forms and interaction from the start.
Figure 3: A sound record/play board, a solar cell battery charger, a push button and a magnetic switch were used in this prototype.
Figure 4: By embedding a tablet in a form resembling binoculars we create an augmented reality view of the past.
Embedding
What was the design concept?
Many of the visitors to the cemetery are unaware that the
place is, in fact, a cemetery as a large section has been
converted to parkland. Most people come not to visit graves
but to exercise, eat lunch, or walk their dogs. From the main
paths through this park some areas of the cemetery (such as
the catacombs) are visible, but there are no real clues
supplied as to their purpose or history. We aimed to expose
the visitors to some of this information in an engaging way.
How did the prototype capture the concept?
Augmented reality is becoming commonplace on tablets: by
embedding a tablet device in a custom case that resembled a
set of binoculars we push visitors to look at a familiar space
in a different way (Fig. 4). What they see is the cemetery as
it is now overlaid with a digital reconstruction of historical
views. For instance, areas of the cemetery that have been
cleared show the lawn full with gravestones. Visitors can
also “look inside” sealed structures such as catacombs or
see the original procession path, later covered by burials.
What was learned through the prototype?
Different forms, initially in cardboard then in laser-cut
plywood (Fig. 4b) were tried out and these led to a number
of considerations. By just hiding the controls and only
showing the display area the embedded tablet loses its
original feel and becomes a new device. This new device is
suitable for any technical ability as its binoculars form
affords the well-known behaviour of exploring the
surrounding area by sight, focussing the attention of the
watcher on what is there.
The form changes the interaction: the encasing creates
darkness essential to see a screen outdoor (Fig. 4c); it also
provides an optimal distance and angle of view (Fig. 4d).
The integration of form (the binoculars) and function (the
tablet) was not without obstacles: we wanted to embed the
tablet completely (Fig. 4a) but such an enclosure for the
Samsung Galaxy Tab 2.0 that we used would be too large to
be comfortably handled. A compromise was found: a box
holding the tablet is fixed to a visor. However as the
resulting display area is much smaller than the tablet's
screen size we are now considering swapping it for a
smartphone that would fit our initial design.
Cracking it open
What was the design concept?
As already mentioned many visitors use the cemetery as a
shortcut, for a lunch stroll or as a place to walk their dog.
They cross the landscape at their own pace generally
following the same path. We wanted to encroach on the
walkers’ path in order to cause them to stop, engage and
interact with that part of the cemetery. A key factor for this
concept was that it must activate based on the presence of a
visitor who is not carrying any specific triggering device.
The design also had to be sympathetic to the landscape and
unobtrusive in its form factor. The resulting prototype was a
birdhouse (Fig. 5a) that is activated by a visitor’s presence
and projects a pattern of flying birds onto the ground to
capture their attention.
How did the prototype capture the concept?
The effect we aimed to achieve is very close to that of
musical projection devices for babies that are currently
available on the market. One such device was dismantled
(Fig. 5b) in order to remove the projection and image
rotation unit. A new picture wheel for the projection of bird
silhouettes and a new housing resembling a bird box were
created in order to produce a prototype that blends into the
landscape. The concept of the birdhouse is of a device
augmenting the environment in a permanent way. We also
considered how to self-power it: a Nickel-Metal Hydride
battery and a solar cell taken from a consumer solarpowered led torch were encased on the birdhouse roof.
Figure 5: A hacked children's light and sound toy allows us to create a low cost projector prototype.
Figure 6: An embedded computer and a Bluetooth speaker create interactive location-based audio in the cemetery.
What was learned through the prototype?
The low-tech LED and lens technology from the toy proved
too weak for projection in daylight or over a long distance.
However, as a proof of concept, the prototype was
successful and well-received when proposed to the
volunteers of the cemetery trust. It prompted interesting
discussions ranging from the importance of illuminating a
path at night to the possibility of changing the projection on
a seasonal base to highlight how the cemetery landscape
changes.
It is clearly possible to overcome the current limitation by
using a pocket projector controlled via a card-size
computer. However the complexity and cost increase
reducing the value of this concept for its final destination, a
public park where vandalism may occur.
Collating
What was the design concept?
Cemeteries are full of stories: the lives of people from all
walks of life can be told in place, offering new perspectives
and elements for reflection on the changes that have
occurred in society. To take advantage of the evocativeness
of the cemetery we envisaged that the place itself could tell
the stories: nearby visitors are attracted to a point of
interest, such as a particular gravestone, by a sound; if they
approach closer a snippet of the story is told. Every point
may have multiple stories, such as the different lives of the
members of a family all buried in the same place, the social
meaning of an epitaph (“the wreck of her husband”) or the
artistic value of a sculpture. Visitors can freely walk the
cemetery following their own mood and choose the type of
story they want to listen to at any point in time.
How did the prototype capture the concept?
The core element of the concept is of the narrative to be
local to a place. Bluetooth loudspeakers offered the desired
functionality: they have a unique identifier (that we can
associate to a place) and can play the sound transmitted by
a Bluetooth-connected device. The first prototype used the
evocative form of a Victorian apothecary bag to host the
transmitter device, but the selection of the type of story by
moving a bottle in a different slot was not convincing. The
second prototype builds upon the natural interaction with a
book (Fig. 6a): each page shows a different perspective
(e.g. medical advancement, social history, personal life) and
the visitor selects the type of story by placing a bookmark
on a particular page. The Bluetooth loudspeakers are hidden
in elements that fit the environment (a wreath and a
birdhouse, Fig. 6b).
A battery-powered hand-sized computer-on-a-board system
(Beagleboard) was combined with a USB Bluetooth dongle
(Fig. 6c) to create a wireless link between the board itself
and Bluetooth speakers which were positioned at the points
of interest. The embedded system contained all the stories
in the form of audio files. Different audio files are played
depending on where the visitor is: a visitor's location is
determined from the Bluetooth loudspeaker’s in-built MAC
address (each loudspeaker is mapped onto a place of
interest), while the measure of the Bluetooth signal strength
provides an estimate of how far the visitor is thus
controlling the playing of a sound to attract interest or to
narrate a story.
Independent powering offers the chance to easily explore
outdoor locations and catch impressions of the real
interaction in space and the effect of audio output in an
open environment.
What was learned through the prototype?
Bluetooth-based distance measurement and timing issues
turned out to be big challenges in realizing the concept. The
large influence of the environment on Bluetooth signal
strength made it difficult to find a set-up that worked
reliably everywhere in the cemetery. Obstacles, other
devices and even height above the ground affected the
signal strength. Finding timing that works well in different
situations and for different walking speeds was also an
issue. While the signal strength problem is present in every
wireless technology, many of the timing problems came
from the limitations of Bluetooth technology with regard to
searching for devices, pairing and establishing a
connection.
A video recording the interaction of attracting and
storytelling in place (Fig. 5d) was shown to the cemetery
volunteers in a workshop and was very well received: the
idea of the deceased or their family telling the story was
powerful and emotionally charged. Interesting comments
were made on the possibility of creating stories that
connected many places and many people, possibly those
who worked together or who funded charities and schools.
Participants also discussed the effect of different media
with audio being potentially intrusive but also potentially
intriguing for other people passing by.
FAST PROTOTYPING TANGIBLE INTERACTION
The Process
polished to make it fit the context and support a better
communication of the envisaged used.
Reflecting on our experience we see five steps in fast
prototyping as a mean to explore new areas of tangible
interaction: formulating a concept, selecting the technology,
designing the form, critically evaluate the outcome and
reflect on the findings.
Guidelines and Tips
The starting point is a concept: decide what the most
interesting aspect to explore is, as the prototype will focus
solely on that. Decomposing the concept to the core
elements is also a way of clarifying what the designers want
to do and why. Clearly, this is a process of pruning and one
should be prepared to forgo some important aspects, which
may be picked up again at a later stage.
Watch your environment: There are many ubiquitous
technologies out there from movement sensors for
automatic outdoor lighting to singing greeting cards. Also
the ever-increasing range of apps makes smart phones and
tablets a potential source of (almost) already-made
functionalities that can be exploited for fast prototyping.
Search for the simplest solution first.
Once the concept has been determined, the next step is the
selection of existing technology. This step requires much
comparison and some decision-making that will affect the
prototype. For example, when selecting the dictaphone that
would become the core element of the sound bauble (Fig.
2), considerations of sound quality, recording time,
frequency and method of charging influenced our final
choice. Similarly for the book (Fig. 6) the decision of using
a Beagleboard and a large battery pack affected the size of
the book. We could have probably scaled down in size, for
example by using a Raspberry PI, but familiarity with the
other hardware and software made the Beagleboard more
attractive for fast prototyping.
Inspect toys: Many toys contain low cost sensing and
presentation technology that can be used for simple
interactions. An example of this is our birdhouse projector,
which was based on a light and sound show toy designed
for young children. As unprofessional as this can sound, it
is one of the strategies adopted by professional inventors
while exploring new ideas [8].
Deciding on the form factor is the next step. Although some
ideas may have been sketched at concept generation, the
final form has to take into account the technology. The
main issue is likely to be how to map the intended
interaction onto the device controls. For example, in the
case of the sound bauble (Fig. 2) much work was involved
in figuring out how to activate the touch buttons on the
dictaphone and how to space them out. In the case of the
book (Fig. 6) several methods were investigated in order to
find a simple way to select different types of stories. An
interesting phenomenon in the design of the form is the
inspiration that comes when facing technology constraints,
as with the small photoframe (Fig. 1b) which changed from
a ball that can be open to one to look into.
As discussed above, the purpose of fast prototypes is to
advance our understanding, improve the communication of
ideas and progress toward the optimal solution quickly and
effectively. As such prototypes can be used by the team in
different ways: to provoke discussion with potential
adopters (Fig. 1, Fig. 5); to check the technical feasibility of
a specific interaction (Fig. 3); to investigate how the form
affects the technology (Fig. 4); to gain feedback on
appropriation and use (Fig. 2, Fig. 6). All are forms of
evaluation that trigger reflection on what works and what
needs reconsidering. However, if the prototype is going to
be evaluated with potential adopters, then the form must be
The process for fast prototyping described above gives an
overall framework, but in our experience, other elements
have also proved important. Here we share some guidelines
and tips that other researcher may find useful.
Be quick, be focussed: Ideas are ephemeral so fix your
intuitions in a prototype now. Keeping the flow of creativity
going is more important that perfection: fast prototyping
allows to make, to learn, and to move on.
Take a look at toolkits: Flexible, extensible platforms such
as Arduino or Gadgeteer cover a range of programmable
sensor and actuator technologies that can be used to build a
variety of prototypes. While most of the prototypes
discussed in this paper have not involved such technology,
sometimes they offer the quickest path to a useful
prototype.
Keep it simple: When developing a prototype to explore
the form and interaction of a device it is the overall
impression of the prototype that is important. Accuracy and
reliability are less relevant at this stage: when testing a
prototype one can control and fit the conditions of the test
to the benefit of the prototype.
Function follows form: Dressing up devices in an
appropriate shape covers the original purpose of the
technology used and allows exploration of the concept
itself. The proliferation of desktop laser cutting and 3D
printing makes this easier than ever before. By hiding the
technology we focus our and the adopters’ attention more
fully on the interaction rather than how it works.
Think about energy: Power supply is especially critical for
portable devices. This aspect has to be foreseen when
designing cases and shapes. Having to recharge may limit
how the prototype can be used, both during evaluation and
in actual use. However, there can be some scope for
creativity in how the device can be powered or charged, as
was the case for the recording cartridge or the birdhouse.
Someone has done it before: The Maker movement and
the popularity of venues such as Make magazine and
Instructables.com mean that there are a large number of
resources available on hacking existing devices. This is also
the case with many toolkits, for which you can often find
helpful code snippets or even whole libraries. Similarly,
many interactions can be simulated with smartphones either
by writing new programs or using readily available apps.
CONCLUSIONS
We do not see the types of prototypes discussed here as
alternatives to sketching or cardboard prototypes that can be
constructed on the spot during any creative session. In their
ethos hacked prototypes intend to bring to the fore the
material form and the effect it has on interaction: the feeling
when holding the object, the physical engagement with it,
and the appropriation engendered by possessing one are
insights provided only by ‘the real thing’. For this to occur
the prototype must have been designed with the value of
aesthetic in mind and with enough technology to evoke
aspects of final use in a convincing way. As such these
prototypes embody the designer’s tacit knowledge on which
product or interaction will work in that context and enable
to communicate across different expertise and with users.
Prototypes of the kind we propose are a physical
approximation of ideas and elicit a visceral reaction, an
important feedback in the early stages to (re)orient design.
Although physical prototyping by using existing technology
does not need many resources, the devices and electronics
chosen pose constraints on the form, quality, functionality,
and control. This can be seen in a negative way or as a
positive inspiration for new solutions. Recognizing that a
path leads to a dead end is a positive step in the
construction of the understanding and knowledge needed to
progress particularly when exploring new territories for
which previous experience is very limited. Sketches,
mockups and multiple prototypes may seem to slow down
the process, but they actually generate results faster as it is
highly unlikely that the best solution is the first (or only)
idea. Interesting problems are complex, and a series of early
experimentations is often the best way to decide among
competing directions. The faster we make our idea tangible,
the sooner we will be able to evaluate them, refine them,
and move toward the best solution.
ACKNOWLEDGMENTS
This research was supported by: the EPSRC grant
Engineering for Life (case study 1) and the EC FP7 ‘ICT
for access to cultural resources’ (ICT Call 9: FP7-ICT2011-9) under the Grant Agreement 600851 (case study 2).
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