“The complex technologies the networked city relies upon to produce its effects remain distressingly opaque, even to those exposed to them on a daily basis.” – Adam Greenfield (2009)

Immaterials: light painting WiFi film by Timo Arnall, Jørn Knutsen and Einar Sneve Martinussen.

This project explores the invisible terrain of WiFi networks in urban spaces by light painting signal strength in long-exposure photographs. A four-metre tall measuring rod with 80 points of light reveals cross-sections through WiFi networks using a photographic technique called light-painting.

This builds on a technique that was invented for the 2009 film ‘Immaterials: the Ghost in the Field’ which probed the edges of the invisible fields that surround RFID readers and tags in the world. It also began a series of investigations into what Matt Jones richly summarised as ‘Immaterials’.

While we were mapping out tiny RFID fields, we wondered what it would be like to apply the light painting process to larger-scale fields of Bluetooth, WiFi, GSM and 3G. What if we built huge light painting apparatus that could map out architectural and city-scale networks in the places and spaces they inhabited? We’re still very interested in understanding radio and wireless networks as one of the substrates essential to contemporary design practice.

We built the WiFi measuring rod, a 4-metre tall probe containing 80 lights that respond to the Received Signal Strength (RSSI) of a particular WiFi network. When we walk through architectural, urban spaces with this probe, while taking long-exposure photographs, we visualise the cross-sections, or strata, of WiFi signal strength, situated within photographic urban scenes. The cross-sections are an abstraction of WiFi signal strength, a line graph of RSSI across physical space. Although it can be used to determine actual signal strength at a given point, it is much more interesting as a way of seeing the overall pattern, the relative peaks and the troughs situated in the surrounding physical space.

After a week of walking through urban spaces holding and photographing this instrument, we have a much better sense of the qualities of WiFi in urban spaces, its random crackles, bright and dim spots, its reaction to the massing of buildings, and its broad reach through open areas. The resulting images show some of these qualities, and light painting is a brilliant medium for situating visualisations and data into physical world locations and situations.

Lots more visualisations and ‘making of’ pictures.

Einar writes more about this in an upcoming article called ‘Making material of the Networked City’ in Design Innovation for the Built Environment – Research by Design and the Renovation of Practice. There is also more detail on the project at the YOUrban weblog.

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In this film, Wireless in the world 2, simple visualisations of radio ‘spaces’ are overlaid into urban spaces. The film has been made as a follow up to this video experiment and has been specifically designed for exhibition in HABITAR at LABoral Centro de Arte y Creación Industrial.

Here is an excerpt from the exhibition description:

“Utopian and radical architects in the 1960s predicted that cities in the future would not only be made of brick and mortar, but also defined by bits and flows of information. The urban dweller would become a nomad who inhabits a space in constant flux, mutating in real time. Their vision has taken on new meaning in an age when information networks rule over many of the city’s functions, and define our experiences as much as the physical infrastructures, while mobile technologies transform our sense of time and of space.”

There are photos of the exhibition by Edgar Gonzalez here. The exhibition catalogue with essays by Anne Galloway, Usman Haque, Nicolas Nova and others is available to download here.

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This video is about exploring the spatial qualities of RFID, visualised through an RFID probe, long exposure photography and animation. It features Timo Arnall of the Touch project and Jack Schulze of BERG.

The problem and opportunity of invisibility

RFID is still badly understood as an interactive technology. Many aspects of RFID interaction are fundamentally invisible; as users we experience two objects communicating through the ‘magic’ of radio waves. This invisibility is also key to the controversial aspects of RFID technology; once RFID antennas are hidden inside products or in environments, they can be invoked or initiated without explicit knowledge or permission. (See here for more on the invisibility of radio.)

But invisibility also offers opportunities: the lack of touch is an enormous usability and efficiency leap for many systems we interact with everyday (hence the success of Oyster, Suica and Octopus cards). But there is also the ‘magic’ of nearness one of the most compelling experiential aspects of RFID.

As designers we took this invisibility as a challenge. We needed to know more about the way that RFID technology inhabits space so that we could better understand the kinds of interactions that can be built with it and the ways it can be used effectively and playfully inside physical products.

The experiments

In order to study the readable volume around an RFID reader, we built experimental probes that would flash an LED light when they successfully read an RFID tag. The readable volume is not the same as the radio field, instead it shows the space within the field in which an RFID tag and an RFID reader will interact with each other.

One version of our probe containing a tag and LED light connected to the RFID reader that is being studied.

In a dark room, the probes were moved around the various RFID tags and readers that we wanted to study, with a camera taking long-exposure photographs of the resulting patterns of light. In this way we could build up layers by slicing through the field in different ways, creating animations that clearly reveal the spatial properties of this interaction.

These experiments were carried out in order to help us flesh out our own models of the technology, and were not intended to be scientifically accurate. So although they accurately reflect the behaviour of the technologies in the situations that we work with, there were no controlled environments or settings for generalisable technical accuracy.

Innovations ID 20

The Innovations ID 20 RFID reader has become one of the standard components in a lot of our work, it is small, robust and relatively cheap. So it has been very important for us to gain an understanding of the readable volume it produces when we embed the reader inside products such as Sniff and Skål.

Details: Innovations ID20 low-frequency EM4102 reader, 20mm circular EM4102 tag.

The resulting visualisation shows the way in which we have mapped the boundary of the readable volume, although a tag will read anywhere inside this, we have only mapped the edge for the sake of clarity. From the animation (see the video) we start to clearly see that the readable volume is made up of a strong central sphere, accompanied by a smaller lobe that surrounds the edge of the reader.

Oyster card

Mifare cards are one of the largest public applications of RFID, used in many transit systems around the world such as the Oyster and Suica cards. It has become common to have to touch in and touch out of subway stations, and many people have become accustomed to this interaction. So what does the readable volume around an Oyster card look like?

Details: Standard Mifare Oyster card, probed with a Sonmicro high-frequency reader.

With a square antenna inside the Oyster and the Sonmicro reader, we get an elongated main volume, accompanied by long skinny lobes on each edge of the card. This looks very different from the ID 20 mapping.

Orientation

The first two mappings held the reader and the tag parallel to each other, but we predicted that there would be a higher degree of complexity in the relationship if the tag and the reader moved in different orientations. The rig below was built so that we could control the angle between the reader and the tag, which moved along the surface of the table.

Details: Innovations ID20 low-frequency EM4102 reader, 50mm circular EM4102 tag.

There is clearly enormous physical complexity in this relationship, in the animation we can see the volume growing and shrinking, lobes turning into spheres, and vice-versa. But the animation gives us a very clear picture of the ‘throw’ of the reader onto a single two-dimensional plane, almost like looking at it as a torch.

Parallel and perpendicular

To show the two extremes of the relationship between orientation and the readable volume, we created two mappings, one with the tag parallel to the reader, and the other with the tag perpendicular. We mapped them using two different colours of LED: green for parallel and red for perpendicular.

Details: Innovations ID20 low-frequency EM4102 reader, 20mm circular EM4102 tag.

This image is a composite of the two mappings (see the video for animations of the two mappings separately) and it is clear that the readable volume is significantly different. When the tag is perpendicular to the reader, there is a sizeable gap in the middle of the reader where the tag will not read, creating two readable volumes side by side.

Conclusions

We have been continually challenging the ways in which RFID technology has been framed. It is incredible how often RFID is seen as a long-range ‘detector’ or how little relevant information is contained in technical data-sheets. When this information is the primary material that we are working with as designers, this is highly problematic. By doing these kind of experiments we can re-frame the technology according to our experience of it, and generate our own material knowledge.

One of the early motivations in this project was the way in which the animations really captured our tacit, embodied knowledge of the readable volume in a visual way, it was almost as if you could wave your hand through the floating green LEDs and feel them. Of course we had felt it hundreds of times in experimenting with tags and readers, but we had never seen it captured in an image, in a way that was communicable to others without having them try an interactive demonstrator. With this visual material, we can communicate about RFID in ways that we couldn’t previously.

So we hope that this work goes some way towards building better spatial and gestural models of RFID, as material for designers to build better products and to take full advantage of the various ways in which spatial proximity can be used. And with this better understanding we hope to be able to discuss and design for privacy and the ‘leakage’ of data in a more rigorous way.

Field icon

Download a PDF file of the RFID icon.

This RFID icon is based on the shape of the ‘readable volume’. Created by Timo Arnall & Jack Schulze, it is licensed for use under a Creative Commons Attribution 3.0 Unported License.

Go ahead and use it!

Credits

The project was made by Timo Arnall and Einar Sneve Martinussen from AHO and Jack Schulze from BERG. Thanks to Jørn Knutsen for help in building the rigs.

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The ‘Radiogenic’

Dunne & Raby introduce the idea of ‘Hertzian space’ in Design Noir and Hertzian Tales where they describe a landscape of electronic products creating a “new, invisible but physical environment”.

In Tunable cities they map the radio signals from domestic equipment such as babycoms and begin to examine the “role of electronic products in the aesthetic inhabitation of a rapidly dematerialising, ubiquitous and intelligent environment.” Here there are visualisations of radio fields as bright red spaces overlaid on the streets of Chiswick, London.

Although their work specifically avoided issues around making the invisible visible or visualising radio, it explored the “links between the material and the immaterial that lead to new aesthetic possibilities for life in an electromagnetic environment”.

“It might seem strange to write about radio, a long-established medium, when discussion today centres on cyberspace, virtual reality, networks, smart materials and other electronic tehcnologies. But radio, meaning part of the electromagnetic spectrum is fundamental to electronics. Objects not only “dematerialise” into software in response to minituarisation and replacement by services but literally dematerialise into radiation. All electronic products are hybrids of radiation and matter. [...] Whereas cyberspace is a metaphor that spatialises what happens in computers distributed around the world, radio space is actual and physical, even though our senses detect only a tiny part of it.”

As Matt Jones points out, they go on to coin the term “radiogenic” to describe objects that:

“function as unwitting interfaces between the abstract space of electromagnetism and the material cultures of everyday life, revealing unexpected points of contact between them.”

The Faraday chair offers a slightly more nuanced ‘visualisation’ of the boundaries of electromagnetic waves through a physical object. These works operate by visualising and making tangible the boundaries between electromagnetic phenomena, and as such, serve to highlight and create discourse around the issue of radio in emerging products and systems

Celebrating the magic of remote action

The language used to describe RFID interaction includes closeness, touch, proximity and pointing but there are few explorations of the way that RFID systems shape the gestural and tangible aspects of this interaction. Within Human Computer Interaction (HCI) there is some discussion of the spatial aspects of sensor technologies. For instance Ailisto et al (2003) discuss the ways that RFID creates contactless interactions on mobile phones: “Physical selection may be based on proximity or pointing. In the case of proximity, the selection is activated by bringing the activating device, e.g. a smart phone, close to the target device.”.

In the Touch project we have experimented with the spatial aspects of RFID interaction, developing a tacit design knowledge of the technology over time. At an early RFID hacking workshop with BERG/Schulze & Webb we experimented with playful interactions that involved “the magic of remote action” where invisible interactions triggered events in the world.

This is something we went on to explore in much more detail in the film Nearness, where the relationship between proximity and physical interaction is explored in detail.

In projects like the Graphic language for touch we have begun to find ways of representing invisible radio as a tangible design material in a functional setting.

And in her project the Bubbles of Radio (that emerged from our Fields and Seams brief) Ingeborg Marie Dehs Thomas imagined and visualised many fictional representations of radio fields including Bluetooth and RFID. These drawings provide a playful starting point for the discussion of our relationship to radio fields and the possibilities they open up for interaction.

Exploring and experiencing waves

The political, social and phenomenological aspects of the electromagnetic spectrum are a recurring theme within contemporary media art practice. For instance the exhibition Waves at RIXC tuned in to artistic engagements with the electro-magnetic spectrum and suggested that “artists should take control of the very principles and materiality of the ‘network waves’.”

A common practice is to translate radio space into an audible, sonic experience. In projects like ætherspace, Aeriology, Electroprobes and in many RFID projects some kind of probe that senses radio and offers audible output is held or attached to the body. The experience is then about being mobile, moving through and probing the world to discover how the lanscape and patterns of radio changes through space.

Then there are a number of visual, interactive visualisation projects such as the Wifi camera, the sightseeing telescope that reveals open wifi networks in urban space and the Free Network Visible Network project. In most cases the visual representations of the radio waves are merged and overlaid into optical or video backgrounds of the physical world, in a kind of ‘augmented reality’ genre.

In Edge Town by Ben Hooker and Shona Kitchen visual approaches are used to explore the ways in which we can “design interfaces with the flows of electronic data that run through our cities so that they can be experienced as an enriching complement to other, more ‘earthly’ phenomena.” Their garden-like visualisations represent the desire to turn these invisible flows into something more tangible. In another architectural approach, Pedro Sepulveda-Sandoval proposes the demarcation of public areas that are free of mobile phone signals, using the visual language of yellow/black warning tape.

Artists Ruth Jarman & Joe Gerhardt visualised many kinds of fields in Magnetic Movie, where the fields are seen animated as crackling, pulsing and swirling waves that uncomfortably inhabit physical spaces. This animation reinforced by a strong soundtrack that crackles in time with the motion is one of the most engaging and compelling visualisations of radio fields that we have seen.

Spatial and seamful sensors

For engineers and scientists, accurately modelling and visualising invisible radio fields, and engaging in antenna measurement is a difficult task, if not almost a ‘black art’. Using specialist robotic equipment and slowly measuring the intensity of radio signals at various points in space, it is possible to build up a three dimensional map of a radio field. There are also specialist 3D simulation tools that create models of radio fields and their interactions with physical material. These tools are mainly used to optimise the design of radio antennae, probe and problem-solve radio interference problems in electronic equipment and to assess safety issues with human exposure to radio systems.

In a paper called The spatial character of sensor technology Reeves et al (2006) describe the importance of understanding seams and spatiality in sensor-based systems. Although they concentrate on ‘torch-based’ interactions, their concerns are relevant for other sensor technologies:

“We are primarily concerned with the way in which seams between devices create a particular spatial character for the location in which they are deployed. This spatial character of seams derives from the use of spatially-embedded sensor technologies (e.g., GPS, Wifi, etc.) which are particularly prevalent in ubiquitous computing. Sensor technology plays a fundamental part in the creation of seams, and thus the character of the space in which such technology is deployed. The main issue, then, is how interactive and ubiquitous system design may appropriately address this essential spatiality.”

There is also a discussion of the ‘seamful’ character of many ubiquitous technologies.

Chalmers and Galani (2001) describes the ways in which “wireless networks have distinct physical characteristics such as a tendency to be absorbed by metal, water and other conductive materials, and a pattern of coverage that makes for a limited area of usable network connectivity.” They suggest that there may be a method or conceptual process of ‘seamful design’ that builds upon the way that “people accommodate and take advantage of seams and heterogeneity, in and through the process of interaction.”

“We critique the ‘disappearance’ mentioned by Weiser as a goal for ubicomp, and Dourish’s ‘embodied interaction’ approach to HCI, suggesting that these design ideals may be unachievable or incomplete because they underemphasise the interdependence of ‘invisible’ non-rationalising interaction and focused rationalising interaction within ongoing activity.”

There is something in this ‘seamful design’ process that may help us to understand of the way that we deal with the invisible aspects of radio-based interaction, and the ways that mental models are built out of these systems.

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Right now I am sitting near fourteen objects sending and receiving radio signals, from Oyster cards to mobile phones and wireless routers in a multitude of overlapping and competing fields. Here we are creating communicative material that uses dashed-line abstractions to visualise the presence of wireless technologies in the everyday environment. What if we could see every field produced by an Oyster card or NFC enabled mobile phone for instance?

Using simple abstractions such as the dashed line and the kinds of visual language that we have previously proposed for RFID allow us to quickly communicate aspects such as the spatial properties of wireless technologies that are often overlooked. I’ve been using these images in presentations for a while, to sensitise designers and students to the spatial and embodied properties of RFID, Bluetooth and WIFI.

We are also experimenting with video, where the visualisations are part of an environment in a moving sequence. This is looking like a useful technique for making visual explanations of invisible materials.

Here are more images:

NFC phones and contactless cards.

NFC phones.

Wifi and bluetooth.

An NFC-enabled bus timetable.

An NFC-enabled ‘smart poster’.

An Oyster card reader and cards

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This collection of ‘vernacular’ designs for RFID-based interfaces is extremely interesting for us, as we delve deeper into the visual representation of emerging technologies.

If you have images of good, bad and especially odd interfaces where interaction with an RFID tag or NFC mobile phone is indicated with an icon or an interestingly designed physical enclosure, please add it to the pool by tagging it ‘touch interface’.

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“Natural magnetic fields are revealed as chaotic, ever-changing geometries… Are we observing a series of scientific experiments, the universe in flux, or a documentary of a fictional world?” The stills don’t do the pulsing, crackling, moving visuals justice, I highly recommend that you go and watch the film.

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I’ve had trouble justifying my excitement about this intricate visual detail, so I thought it would be good to collect a bunch of examples from over fifty years of information design history, to show it as a powerful visual element in ubicomp situations.

Even though the dashed line has emerged from a designer’s shorthand and from the limitations of monotone printing techniques, it has a clear and simple visual magic, the ability to express something three- or four-dimensional in two dimensions.

The dashed line as hidden geometry

Examples from Open Here: The Art of Instructional Design, Paul Mijksenaar, Piet Westendorp, 1999.

The dashed line as movement

The line is used to indicate temporal positions:

Examples from Open Here: The Art of Instructional Design, Paul Mijksenaar, Piet Westendorp, 1999.

The dashed line as paths

Very similar to the representations of movement, but the line is used as the path itself:

Examples from Open Here: The Art of Instructional Design, Paul Mijksenaar, Piet Westendorp, 1999.

A more modern image showing an overview of Auto ID RFID supply chain management, by Xplane:

Colin Ware defines dashed, dotted or wavy lines as linking lines:

“A linking line between entities represents some kind of relationship between them. A line linking closed contours can have different colours or other graphical qualities such as waviness, and this effectively represents an attribute or type of relationship.”

From the perceptual syntax of diagrams in Information Visualisation: Perception for Design, Colin Ware, 1999.

The dashed line as expectation

I’ve spoken to some people that have made an association between the dashed line and an ellipsis. This example is taken from the Mac OS X interface, conventionally used to indicate that the action will be followed by another action.

The dashed line as ephemeral material

Examples from Open Here: The Art of Instructional Design, Paul Mijksenaar, Piet Westendorp, 1999.

The dashed line as border or seams

A table of commonly used conventions from Information Graphics, Robert Harris, 1996.

Other examples

This is an example of dashed lines in information design from The Visual Display of Quantitative Information, Edward Tufte, 1983. I get the sense that Tufte prefers a simple, solid line, considering the overuse of patterns a form of chart-junk:

And lastly, an interesting thought from a conversation with Dave Gray, of Xplane and Communication nation:

“I think of lines: double-line, solid, dashed, dotted Similar to typeface conventions such as black, bold, regular, light. It’s a matter of emphasis. The thicker and more solid the line, the stronger the emphasis. A dotted line usually does not indicate “cut here” unless it is combined with a scissors icon. I think that trying to make a direct connection between the dashed line and what it represents may be a red herring. Think of a map, for example: Whether type is bold, all caps, or light relates directly to the designer’s decisions about emphasis, but I am not sure it relates so directly to the subject matter. There are a few direct correlations of this type: for example, type representing water is usually set in italic. I like your use of the dashed line – it is clear that they serve as a guide and invitation to “place things there”.”

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