[PhD] Hertzian Fields: Exploring WiFi microwave signals as a spatial and embodied sensing medium for art

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[PhD] Hertzian Fields: Exploring WiFi microwave signals as a spatial and embodied sensing medium for art

PhD dissertation

Digital Arts and Experimental Media, University of Washington

“One organ, more or less, in our machine, would have given rise to another kind of eloquence, another kind of poetry.”
Charles de Secondat Baron de Montesquieu (Montesquieu, 1757)

Abstract

This dissertation is centered around a series of three artworks (Hertzian Fields) that explore WiFi as a spatial and embodied sensing medium. These works use a new sensing technique developed by the author that leverages the interference of the human body on WiFi signals to create highly responsive live performance and interactive systems.

Hertzian Field #1 (2014) is an augmented reality immersive environment using sound to explore the materiality of WiFi communication through its interaction with space and the human body.
Hertzian Field #2 (2016) is a 20′-25′ augmented reality immersive performance for solo performer, WiFi fields, computers and surround sound that conjures a phenomenology of the hertzian medium explored through sound and movement.
The Water Within (Hertzian Field #3 and #3.1) is a reactive wet sauna: an intimate multi-sensory environment of complete immersion, combining WiFi sensing fields, machine listening software, embedded 3D sound, hot steam, and architectural design. Steered by the flows and variable densities of water molecules traced in steam and bodies by (ab)using WiFi, it creates a regenerative post-relational experience that celebrates interference, signal-loss, and disconnecting. The piece exists in two iterations and formats: an interactive installation (2016) and a composed interactive experience (2018).

The dissertation describes the author’s conceptual and technical approach in using WiFi microwave signals as an artistic medium. It also examines the background, context, ideas and research processes that led to the creation of these works. In doing so, it lays the foundation for developing a better and deeper understanding of microwaves and WiFi signals, investigates their artistic potential, and discusses related approaches by other artists.

Chapter One (Introduction: The hertzian medium) introduces core ideas and concepts regarding the medium. This includes: a discussion on the impact of wirelessness in contemporary living and how it has transformed our interactions with and understanding of the world; an overview of the physics of electromagnetism and the electromagnetic spectrum; and an investigation of the hertzian (i.e. radio and microwaves) as a multilayered medium consisting of seven interconnected layers: physics, science, imagination, engineering, use, impact, regulation.

Chapter Two (The birth of a medium: Energy becomes technology) introduces a media archaeological approach as a method for grasping what the medium affords, and how our imagination of what we can use it for has developed over time. It presents an overview of key developments in hertzian science, imagined and realized applications, and their impact. This chapter focuses primarily on the early years around Heinrich Hertz’s discovery of electromagnetism, looking at the birth of wireless technologies relevant to the Hertzian Field series: communication, broadcast, hacking and electronic warfare, navigation, meteorology, radio astronomy, and radar, before closing with a section on the development of WiFi.

Chapter Three (Radar and Direction-Finding in sonic art and beyond) surveys musical instruments and artworks based on spatial and/or embodied uses of the hertzian as a sensing medium. The emphasis is on sound-centric practices and specific technologies that have been used to this extent: from capacitative / electric field sensing, to musical instruments utilizing direction-finding principles, to spatial uses of broadcast radio, to doppler radar systems. Instruments discussed include: Theremin and Terpsitone; Pupitre d’Espace; Radio Baton; Marimba Lumina. Artworks by the following artists are examined: Max Neuhaus; Edwin van der Heide; Christina Kubisch; John Cage; Philippa Cullen; Liz Phillips; Sonia Cillari; Tetsuo Kogawa; Anna Friz; Edward Ihnatowicz; Steve Mann; Joe Paradiso / MIT Lab; Arthur Elsenaar; Godfried-Willem Raes.

Chapter Four (First hertzian explorations: From the network to the body, from WiFi to Radar) turns to the author’s own work. It presents the first phase (2010-14) of his research trajectory on the hertzian medium, and introduces three projects (1,2,3) in which he explored WiFi and broadcast radio.

Chapter Five (Ubiquitous sensing with radio waves and microwaves) dives into the technological context influencing the author’s research. It introduces the field of Ubiquitous Sensing and discusses relevant localization and device-free sensing techniques, concluding with a discussion on the physics and biological factors involved so as to comprehend how and why such techniques work.

Chapter Six (Wireless Information Retrieval: Sensing with WiFi signals) presents the device- free WiFi-sensing technique that the author developed for the Hertzian Field series. Combining elements from Ubiquitous Sensing and Music Information Retrieval, this technique performs multi-layered feature extraction on the Received Signal Strength Indication (RSSI) of WiFi Beacon frames to deduce a variety of information related to the movement of uninstrumented bodies, and to changes in environmental factors (e.g. humidity).

Chapter Seven (Composing Hertzian Fields) discusses strategies for creating works with this technique, and examines the three works of the Hertzian Field series in detail. It finally touches on ideas for future work by the author.

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