Hi! Welcome to the presentation of our pictorial
of Crafting On-Skin Interfaces: An Embodied Prototyping Journey.
This work has been developed at the Eindhoven University of Technology,
together with the Dutch organization for scientific research, and national and local partners from the industry and academy.
It has been increasing attention from the design and Human-Computer Interaction community to this research topic,
yet, there are diverse challenges that limit the development and implementation of OSI in real-life contexts.
It is still very difficult to develop OSI systems that are robust enough to be deployed
and scaled up to mass production and the consumer market.
Furthermore, Some of the existing design principles for user interfaces must be questioned
and adjusted before being applied to the design of on-skin interfaces,
as these do not account for their unique physical and psychological characteristics.
Due to the integration of OSI into the human body, one interesting
direction to explore their intrinsic advantages and differences over
other types of interfaces are to address their potential association with a higher bodily self-consciousness.
As suggested by Tieriet al, 2016, such association might be possible by exploring the capability of the on-skin interfaces
the capability of eliciting the feeling of body ownership through on-skin feedback as an illusory body continuity mechanism
To address the topic of OSI, we emphasize the potential of
To start our first-person perspective approach we developed a low-fi prototype of on-skin interfaces.
For this, we made skin stickers to manually track daily habits such as training execution or water intake.
The idea was to explore ways of visualizing “dynamic” personal data on the body.
As a first-person perspective exercise, we gained insights on
the social and personal implications of displaying data on the skin.
People were intrigued by the purpose of the stickers, recurringly asking about their meaning.
We related this to the following factors: the stickers were located on visible, uncovered, and meaningful body spots
such as the forearms and wrists, unlike traditional
tattoos, these had extremely vivid colors, creating a high contrast with the skin tone,
the graphics changed over time, introducing new shapes, patterns, and colors, and did not represent data in a literal fashion.
Making public and constantly visible self-related data such as training habits and water intake,
increased the awareness on those topics.
We also conducted a co-creation session with a tattoo artist and a client.
Being part of its design and realization process, we better grasped
the intimacy a tattoo represents for both the tattoo artist and the client
Through this immersion, we learned that the skin is a very delicate,
valuable, and sensible material that must be treated with care and precaution.
Placing elements on the skin goes beyond wearability factors, and it entails a very intimate perception and interaction with this element.
People might not want to place anything on their skin, but elements with the meaningful and actual value for themselves.
As part of our exploration, we contextualized our project within
recreational running as an interesting case study for on-skin interfaces applications.
This due to the popularity of running-related wearable devices, together with the opportunities on-skin interfaces represents for this market.
For this, we developed a simple but effective wearable system to monitor running technique and display knee impact on the body of the user.
While interesting to gain knowledge and insights on the topic,
this low fidelity OSI did not fully feel like a skin-like interface but a wearable device.
The materiality and feedback mechanisms implemented in OSI must
resemble organic and bodily principles that allow them to blend into the human.
Another insight was that on-skin interfaces might implement more
than one feedback modality and rely on more than one sense to
overcome the accessibility limitations inherent to the shape of the body and on-body location.
According to our initial theoretical approach and early prototypes and first-person perspective approach,
we defined four initial design principles to frame our process and future exploration as follow
As the skin can be considered a public interface,
when designing OSI, access to the personal related information to
the people in the vicinity must be restricted while being understandable and meaningful for the users themselves.
While open for interpretation, On-Skin Interfaces must keep their
actual meaning private, only fully understandable for the user who “wears” it.
Alike “conventional” wearable devices,
On-Skin Interfaces must be easy to understand and reach by the users.
As the skin offers a myriad of body locations to install OSI for in-situ data representation,
access and reachability must not be compromised
Translating the properties of skin reactions such as skin bruises
could enable On-Skin Interfaces to blend and be fully integrated within the human body.
To be able to blend with the human body and to elicit an illusory feeling of body continuity,
OSI must mimic the appearance, feeling, behavior, and sensorial and physical properties of the human skin.
Imagine a wearable interface using artificial sweating to provide feedback and bodily-related information to the users.
This might open opportunities for richer and more intuitive interaction modalities.
OSI must resemble and be inspired by the human body and its amazing sensing capabilities,
responsive materials, and advanced organic mechanisms that offer intuitive,
embodied, and efficient feedback, experiences, and interactions.
Using our initial design principles, we ideated to design an On-Skin
Interface able to represent biofeedback by mimicking bodily feedback mechanisms.
This helped us to visualize possible shapes and relevant body locations for the OSI to be developed in the process.
Following our insights and ideas, we explored different materials, shapes, and feedback modalities.
For instance, we created a thermochromic patch that delivers visual and haptic feedback in the form of an itchy sensation.
Similar to the findings of Pohl & Hornbæk 2018, the tickling sensation does a good job resembling skin and body’s own dynamic
feedback mechanisms. Yet, there are several limitations
in terms of usability and safety. Sweat or water could either damage the components or alter their electrical
This could lead to major skin irritations and discomfort.
It also requires a substantial power supply to work properly, limiting its use in the context of recreational running.
We also created hydro-chromic patches to mimic the color changing of the skin and the sweat as an effective,
natural and powerful feedback mechanism.
This type of feedback mechanism could be implemented as an early warning system,
to alert runners of potential bodily damage or injury caused by, for instance, excessive effort or physical stress.
During our test, fluids were perceived as a very unconventional
feedback mechanism for an artificial system, hence as a more organic way to represent bodily-related data.
Following our explorations, we further developed a patch using fluids and color-changing patterns.
This patch was designed to be installed close to the knee of a runner.
Once the impact detected by sensors in the sole of the shoe was too high,
the patch started changing its color and getting wet, representing a wound or blister
This patch was tested during a full marathon event.
It exhibited the potential to be used by recreational runners, ideally running shorter distances.
Although we used the system to monitor and represent foot-strike-related information,
OSI are versatile devices that can easily be placed and accommodated on any spot of the skin and body shapes.
Hence, OSI have the potential to be implemented in different sports scenarios and display any type of context-specific information.
Finally, we reflected on the initial design principles and reformulated
them according to the insights a learning we got through our prototyping journey as follow:
Meaningfulness: The skin not only protects us from the environment but also defines our identity and contact with the outside world.
As we learned from the tattooing exercise and aligned with the work of You et al. and Withana et al.,
the design of OSI must facilitate the customization and representation of meaningful on-body information according to the
cultural values, social factors, and the personal taste of individuals.
Privacy: Considering the skin as a public interface has several design implications.
As we experienced, it is common for people to hide and encrypt meaning in their tattoos.
As tattoos often represent personal experiences or intimate information, they are rarely literal representations of the meaning they contain.
We propose to approach the privacy component of OSI in the same fashion.
As suggested by You et al., the social and public perception of using OSI potentially determines the user acceptance of this technology.
The implications of OSI in terms of privacy should of course be considered according to their context of implementation.
The cultural and social dynamics might influence their acceptance, interpretation, and use.
Location: As the skin offers a wide range of body locations where the OSI can be placed,
using feedback and representation modalities that rely on more than one sense is crucial for successful OSI.
As we learned from our running-related activities, the access to the
feedback and information delivered by OSI systems must be fluent, clear, and consistent.
Furthermore, and like privacy, the location might be influenced by cultural, social,
and personal factors that must be considered before starting the design of OSI.
Some people would prefer to place OSI in body spots that are not cover by clothing,
yet this differs across cultural backgrounds. In this sense,
a balance between usability properties and contextual factors is essential.
we proposed to place them at a higher level within the design process.
These represent the core values and differentiation factors between OSI and conventional wearable devices.
We highlight the importance of focusing the design of OSI on the effort of resembling bodily-own processes and structures.
For instance, Röddiger et al., intend to mimic UI interface gestures on the skin.
While this is a meaningful contribution, our intention is different.
We aim to contribute to the augmentation of the human body
by using its intrinsic properties and qualities