built-in flashlight. The challenge
is to find applications for the new
projectors that will be just as
attractive to the hundreds of millions of people currently under-served by computing technology
as they are to those accustomed to
ubiquitous personal technology.
It is easy to become breathlessly excited about the possibilities that a new technology
brings. Positive scripts for the
dramatic worlds we envisage
should always be balanced with
an appreciation of the less comfortable potential negatives.
Consider, then, sharing. As
noted earlier, the always-available
large-scale display facilitates collaboration, but it could also be
easy to accidently share private
information with passers-by.
Especially with projector phones,
it would be easy to publicly reveal
private information, such as messages or calendar entries. In currently available commercial mobile
phones with pico projectors, there
are no privacy mechanisms to
prevent this. As today’s projector
phones are just projecting a mirrored image of the device’s display,
there is no way of hiding incoming
messages or caller IDs from others
when using the projection.
The ability to project from a distance also could lead to annoyance
or danger for others, either accidently or intentionally. Passers-by
can be temporarily blinded when
the projection moves and interferes with their field of view. This
would be especially dangerous for
drivers, dazzled, say, by people
in the street playing projector
games. Furthermore, it is possible
to project symbols or words onto
objects and people without their
knowledge or agreement. Julius
1. Rukzio, E., Holleis, P., and Gellersen, H. Personal
projectors for pervasive computing. IEEE Pervasive
Computing. Feb. 2011.
2. See http://www.nttdocomo.com/features/mobil-
3. Rapp, S., Michelitsch, G., Osen, M., Williams,
J., Barbish, M., Bohan, R., Valsan, Z., and Emel,
M. Spotlight navigation: Interaction with a handheld projection device. Advances in Pervasive
Computing: A Collection of Contributions Presented
at PERVASIVE 2004. Oesterreichische Computer
Gesellschaft, 2004, 397-400.
4. Cao, X., Forlines, C., and Balakrishnan, R.
Multiuser interaction using handheld projectors.
Proc. UIST’07. ACM Press, 2007, 43-52.
5. Virolainen, A., Åkerman, P., and Häkkilä, J. Burn-to-share—Content sharing with mobile projectors.
Proc. Mobile and Ubiquitous Multimedia (MUM). 2010.
6. Mistry, P. and Maes, P. SixthSense—A wearable
gestural interface. In Proc. of SIGGRAPH Asia 2009,
Emerging Technologies ( Yokohama, Japan). 2009.
7. See http://www.juliusvonbismarck.com/fulgurator/
von Bismarck does this with his
“Image Fulgurator” as a form of art
[ 7]; what if such practices became
widespread? It is uncertain what
social norms or even laws to limit
public projection will develop.
After the introduction of integrated speakers, many people listened
publicly to loud music. However,
today norms exist that constrain
most people from doing so. With
projectors, though, making the
display private is clearly not an
option. There could then be a risk
that future mobile devices would
be capable of not only spamming
our auditory sense but also visually polluting the environment.
ABOUT THE AUTHORS
Raimund Dachselt is a professor
for user interface and software
engineering at the University of
It is, of course, always dangerous to make predictions about
technology. Even so, let’s end this
article by plotting the trajectory
for picos. Within the next five
years, we might expect a large
proportion of smartphones to
have a built-in projector. Initially,
these will be used for the sorts
of work and play we already see
on touch devices: showing and
chatting about pictures, laughing
at funny videos, plotting a route
on a map, and gaming. It’s likely
that by then the devices’ sensors—cameras and motion sensors—will enhance the interaction
richness. They will then provide
portable surface computing.
The second wave—within 10
years—will see them become an
important platform for a range
of digital-physical augmentations. By then, projectors will not
be simply handheld but attachable, wearable, and embedded.
And perhaps by then we will be
able to lift our eyes from our
handheld mobiles and enjoy a
fused physical-digital experience.
Now, that would be magical.
Jonna Häkkilä is a docent at the
University of Oulu, Finland, and
works as a research leader at
Nokia Research Center, Finland,
where she led user-experience
and concepting teams from 2007
Matt Jones is a professor of computer science at Swansea
Markus Löchtefeld is a researcher
at the German Research Centre
for Artificial Intelligence (DFKI) in
Saarbrücken, where he is working
in the Innovative Retail
Michael Rohs is an assistant professor at the Institute for Media
Informatics of the University of
Ludwig-Maximilians-Universität München), heading the
Mobile and Physical Human-Computer Interaction group.
Enrico Rukzio is an assistant professor at the University of
Duisburg-Essen and a lecturer at
March + April 2012
© 2012 ACM 1072-5220/12/03 $10.00