Demonstrating Fluito: A playful floatation tank experience
Maria F. Montoya
YuYang Ji
Sarah Jane Pell
Florian ‘Floyd’ Mueller

maria@exertiongameslab.org
Exertion Games Lab, Department of Human-Centred Computing, Monash University
Melbourne, Victoria, Australia
maria@exertiongameslab.org

ABSTRACTThe use of technologies for interactions in bodies of water has
fostered the WaterHCI field. However, the interactive systems proposed for water activities have, so far, primarily focused on supporting instrumental and performance aspects. In contrast, the useof interactive technology for experiential purposes, such as waterplay, appears to be underexplored. We designed Fluito, a playful
floatation tank experience, to expand discovery potentials. Fluito
has a unique combination of technology (a floatation tank, a virtual reality headset, a heart rate sensor, and a pneumatic system)that leverages water affordances to create and amplify different
experiences, such as play, relaxation, and bodily illusions. The CHI
community will benefit from our prototype through the novel experiences it affords, difficult to describe in words, and the first-handaccounts it can facilitate, which is useful for inspiring the designcommunity towards future playful water experiences.

CCS CONCEPTS• Human-centered computing → Interaction paradigms.

KEYWORDS
Water, floatation tank, flotation pod, extended reality, WaterHCI,
water activities, playful experiencein water (e.g., see systems that help rowers improve their techniqueto go faster [26]). Moreover, these systems have often been tested byadopting a technology-first approach, where researchers appear tofocus on the system’s technology and usability instead of the user’s
experience [9]. Hence, the design of interactive systems for experiential purposes, such as water play, appears to be underexplored. In
consequence, there is limited understanding of the user experiences
while interacting with technology in water. To explore this opportunity, we designed "Fluito," a playful floatation tank experience (Fig.
1). A floatation tank, also known as a sensory deprivation tank, is abathtub filled with water heated to skin temperature (35° Celsius)
and saturated with Epsom salts (approx. 20%) that increase water’s buoyancy, allowing for floatation without much effort [15].We
developed Fluito as an extended reality (XR) system, integrating
multiple interactive technologies: a floatation tank with ambient
lighting, a virtual environment delivered via a virtual reality (VR)headset, controlled with a heart rate (HR) sensor and slight head
movements that trigger a pneumatic system to deliver tactile feedback (Fig. 1). We exploit Fluito’s capacity to facilitate a playful water
experience by demonstrating its ability to amplify different user
experiences afforded by the body-technology-water integration,such as relaxation and bodily illusions.

ACM Reference Format:
Maria F. Montoya, YuYang Ji, Sarah Jane Pell, and Florian ‘Floyd’ Mueller.
2023. Demonstrating Fluito: A playful floatation tank experience. In Extended
Abstracts of the 2023 CHI Conference on Human Factors in Computing Systems(CHI EA ’23), April 23–28, 2023, Hamburg, Germany. ACM, New York, NY,
USA, 4 pages. https://doi.org/10.1145/3544549.3583908

1

INTRODUCTION

The introduction of interactive technology to water activities is increasingly gaining the attention of researchers in HCI leading to thedevelopment of the WaterHCI [9]. We note that the design of suchinteractive systems has mostly prioritized supporting instrumental
aspects of water activities, such as improving athletic performance
Permission to make digital or hard copies of part or all of this work for personal orclassroom use is granted without fee provided that copies are not made or distributedfor profit or commercial advantage and that copies bear this notice and the full citationon the first page. Copyrights for third-party components of this work must be honored.
For all other uses, contact the owner/author(s).
CHI EA ’23, April 23–28, 2023, Hamburg, Germany© 2023 Copyright held by the owner/author(s).
ACM ISBN 978-1-4503-9422-2/23/04.
https://doi.org/10.1145/3544549.3583908

Figure 1: People using Fluito system. Left: one person inside
Fluito’s floatation tank wearing the VR headset and the HR
sensor. Right: another person inside Fluito’s floatation tankwearing VR headset and the HR sensor experiencing the
bubbles triggered by the interactive pumps.

2

RELATED WORK

We now present lessons learned from prior WaterHCI research,with a focus on the use of XR systems in floatation tanks. Few

CHI EA ’23, April 23–28, 2023, Hamburg, Germany

WaterHCI systems have explored XR technology for bodies of water [8], and specifically for floatation tanks. We hypothesize that
this is because these systems are often not easily accessible. For
example, Ballast VR, a commercial recreational experience uses acustom-made headset called “DIVR”, which costs approx. $ 50-70K
USD [2]. One exception is the work by Mann et al. [18] [19, 20]
where the authors designed a VR game for flotation tanks in whichusers can interact with other tank users, connected over the internet, by watching visual representations of sound waves produced
when they sing together (captured via a microphone in the tank).
This work encourages social interaction while in the tank, suggesting that technology could enrich the tank experience. This systemsuggests that VR interactive technology can support the playful
activities while floating, however, not much is known about theassociated user experience. In particular, we were inspired by priorwork on digital play that highlighted that technologies are particularly good at facilitating playful experiences such as exploration,
discovery and relaxation [16], and hence we focused on these, as
initial starting point, in our work for now. Moreover, we were inspired by this work and wondered if future designs could leverageother interactions that water can facilitate more thoroughly, suchas the haptic feedback opportunity water affords [17].
On the other hand, industry has commercialized VR systems infloatation tanks [3], demonstrating that off-the-shelf VR systems(such as Oculus Quest) and flotation tanks can work well together.
In addition, VR discourse articulates the advantages that VR canbring to technological interactions, such as control over visual andauditory feedback and new simulated virtual world possibilities[14]. Therefore we also considered the combination of experiencing
simulated worlds in VR headsets while in contact with water. We
anticipate that this combination can be advantageous to encourageplay through visual elements, while also immersive, thanks to theisolation provided by the tank. Moreover, prior on-land work has
proposed that VR can complement haptics to augment the sense ofrealism and engagement [11, 13]. Thus, we predict that a similar
combination of VR and haptics could benefit waterHCI systems,
creating a water-XR system.
Although recent explorationin floatation tanks have led to individual reports or online vlogs[5, 8] as well as art provocations [7],we still know little about the design challenges and associated user
experience, hence, our work aims to begin building this knowledge
aiming to start answering the research question: How do we design
playful interactive flotation tank experiences?.

3

DESING OF FLUITO

We designed Fluito (Fig. 2), a novel water-based XR system, inorder to begin answering the research question. The design ofFluito followed the soma design methodology [12, 21]. By following this method and being informed by the related work, we aimed
to integrate the three agents of the interaction, the body (soma),the technology, and the water, and synergistically work towards aplayful experience in a floatation tank. In the soma design prototyping phases, we carried out three 30-minute sessions over three
weeks (one per week) in the flotation tank that was installed in
our laboratory [1]. We confirmed that using VR allows creating astimulating visual experience, encouraging playful elements suchMontoya et al.

as exploration, relaxation, and captivation, as prior work suggested[16]. We evaluated the use of different technologies while floating,including various VR headsets and environments, with a range oftactile feedback modalities, such as a pneumatic air pump triggering
bubbles, and a water pump triggering water jets on the immersed
hands and feet. Based on the learnings from this prototyping [21],our design decisions can be summarized as follow:
We chose the Oculus Quest 2 VR headset to provide visual andauditory feedback. While not fully waterproof, we determined thatthe headset can be suitable for a flotation tank experience, as flotation tank participants keep their heads above water due to the highsalt content. The factors for opting for this existing stand-alone
headset included availability, accessibility, and performance (image
resolution).
Our soma design prototyping also revealed that the floatation
tank’s space is inadequate to perform gross-motor movements that
Oculus controllers’ sensors usually encourage. We decided not to
use the Oculus controllers but rather to leave participants’ hands
free to support comfortable floating, without fear of hitting any
walls. We are aware that our flotation tank is restricted in width(1.5m), and although larger flotation tanks exist [35]. Hence, we
decided not to encourage hands or arm body movements throughour design, instead, we employed the use of the headset’s IMU sensors. The soma design prototyping revealed that moving the headin a flotation tank requires much more deliberate attention than inland-based activities. As we wanted to avoid strenuous head movements (as sometimes required in traditional VR experiences), we
limited the range of the head movements participants were invited
to perform in the software. We also provide a flotation neck pillow(common in flotation spas) to ensure a comfortable experience andsupport the slight head movements (turning left/right) we intended
as input.
We monitor participants’ HR to support safety, as usual in floatation tank studies [15]. We also leverage HR as input for the experience, inspired by previous work using it as a playful mechanic[7, 24]. Our soma design experience also speaks to this, as we foundthat the floatation tank amplifies one’s awareness of breathing andHR, encouraging relaxation and self-awareness. Then, we decided
to sense breathing via the headset’s microphone to inform the movement of virtual focal objects in the VR environment. We use the"Polar Verity" HR sensor as input for background changes in the VR
environment. Changes are triggered when the HR exceeds 80 bpm(the normal resting heart rate in healthy adults [22, 23]), inspiredby prior work with open feedback loops using this threshold [10].
Finally, our soma design prototyping showed that the sensationof bubbles touching the skin while submerged in water can bedelightful, added a feeling of relaxation, and we envisaged thatit could be used as a playful reward. Moreover, as suggested byprior work, we hoped that tactile feedback, when synchronizedwith visual feedback in VR, could increase overall immersion [13].
The result of our design was “Fluito” (Latin for “float”), a novel
extended reality system aimed to provide a playful water experience and amplify the benefits of being in water, such as relaxationand pleasure (Fig. 2). We found the waterproof “Polar Verity” lightbased sensor to be the best wireless HR solution with real-time datatransfer for the VR development platform Unity 3D, supported by
the physiological plug-in “Excite-O-Meter” [25]. We also found air

Demonstrating Fluito: A playful floatation tank experience

CHI EA ’23, April 23–28, 2023, Hamburg, Germany

pumps to create bubbles inside the tank as the best solution forour haptic stimuli since they can be placed outside the tank, delivering air through hoses attached to the tank’s walls. The custom
pneumatic system consists of four 5V air pumps connected to an“ESP8266” microcontroller. The microcontroller wirelessly communicates with the Unity 3D over WiFi using the Uduino plugin [4]and Arduino Servo libraries.

• Onboarding and offboarding to Fluito’s water experience:
Fluitos’ journey begins in a virtual water scene, where theparticipant’s avatar is floating in an infinite ocean at nightwith a sky full of stars, hearing the ocean’s small waves(Fig. 3A). A water spirit (as depicted in the middle of figure3A) emerges and invites the participant to take a journey
together. This virtual scene repeats at the end to offboard
the participant: the water spirit emerges from the ocean andthanks the participant for participating in the journey.
• Underwater scene: The first interactive scene, where the participant dives into a virtual underwater scene (Fig. 3B). The
participant is encouraged to explore the environment fullof sealife: they receive auditory and textual instructions tosearch for emerging lights by performing small head movements and breathing them “in,” promoting rhythmic breathing to facilitate relaxation and breath awareness. The air
pumps activate if the participant is pointing to the lights
with their head and breathing aloud. The environment willchange to red if the participant’s HR is above 80 bpm.
• Psychedelic water scene: The participant enters a “psychedelic”
water scene, where they see a bright horizon with floatingislands, waterfalls, and planets while hearing relaxing music(Fig. 3C). The water spirit invites the participant to collectwater droplets approaching the participant’s avatar position.
The participant guides the water spirit via head movements
to collect the water droplets. If a water droplet is collected,
the air pumps are activated triggering the bubbles. Again,
the environment changes to red if the HR exceeds 80 bpm.
• Rainy water scene: In this final scene, the participant is transported to the top of a cloud in the sky, where they can hearand see the wind, cyclones, dark clouds, and rain. As theparticipant’s avatar rises through the clouds, they collectthe moving cyclones with their head movements, triggering
the bubbles. The environment will change to red if the HR
is above 80 bpm. Additionally, the rain and the storm will
activate in response (Fig. 3D).

Figure 2: Components of Fluito. Left: input from participant
to Fluito. Right: output from Fluito to participant.

3.1

Experiencing Fluito

Experiencing Fluito means joining a journey guided by a virtualwater spirit. Through this journey, both the water spirit and theparticipant will (hopefully) transform themselves while cooperating: the participant will help the water spirit regain life, and thewater spirit will give the participant a superpower: the ability to experience their body in new ways. Furthermore, the water spirit will
guide the participant through different VR worlds where they mustovercome various challenges, such as controlling their breathing
and guiding the water spirit in collecting virtual objects. The VR
scenes and how the participants interact with them are explained
as follows:

4

Figure 3: A) The onboarding and offboarding scene, where thewater spirit says welcome and goodbye. B) The underwater
scene, where participants use their breath to collect lights. C)
The psychedelic space water scene, where participants collectwater droplets. D) The rainy water scene, where participants
rise to the sky (note, it started to rain, and the color is red
due to the HR > threshold).

FLUITO DEMONSTRATION

A study with 13 participants [6] helped determine a suitable design
implementation for a public demonstration at CHI’23 Interactivity.
Furthermore, we have experience having demonstrated Fluito informally over an extended period of time. A public demonstration
affords the opportunity to showcase a feasible integration of thebody, technology, and water to create a playful experience facilitating the natural benefits of floating in the water. Furthermore, apublic demonstration will give attendees interested in the emerging
field of waterHCl an understanding of the design of playful water
experiences using interactive technology in floatation tanks.

5

CONCLUSION

We demonstrated a novel design called Fluito for playful water
experiences in a floatation tank. We implemented Fluito through asoma design methodology, integrating the human body, technology
and water to synergistically facilitate the benefits of being playful in the water. Our aim is to inspire HCI researchers to develop

CHI EA ’23, April 23–28, 2023, Hamburg, Germany

playful experiences in water by leveraging technologies and potentials in the emerging field of WaterHCI. Demonstrating Fluito
offers the opportunity to discuss novel extended reality systems
while offering a unique immersive journey to attendees. Our work
provides a foundation for researchers to explore these design considerations when designing for water interactions, particularly inan experiential context such as play.

REFERENCES[1] March 2022. Amazing Float Tanks | Dreampod. https://www.dream-pod.com/thedreampod-home-pro/[2] March 2022. Ballast VR – Virtual Reality for Waterparks. https://www.ballastvr.
com[3] March 2022. Space VR. https://spacevr.co/[4] March 2022. Uduino. https://marcteyssier.com/uduino/[5] March 2022. Virtual Reality and Sensory Deprivation. https://www.matrise.no/
2018/10/sensory-deprivation-floating-in-virtual-reality-floatation-tank/[6] "Montoya et al. In preparation for submission". A playful VR floatation tankexperience: Towards understanding the design of playful water experiences.
[7] Judith Amores, Anna Fusté, Robert Richer, and Pattie Maes. 2019. Deep Reality:
An Underwater VR experience to promote relaxation by unconscious HR, EDA
and brain activity biofeedback. (2019).
[8] Till Bödeker. 2023. Sensory Deprivation. w/k-Zwischen Wissenschaft & Kunst(2023).
[9] Christal Clashing, Ian Smith, Maria F. Montoya, Rakesh Patibanda, Swamy Ananthanarayan, Sarah Jane Pell, and Florian Floyd Mueller. 2022. Going into Depth:
Learning from a Survey of Interactive Designs for Aquatic Recreation. In Designing Interactive Systems Conference (DIS ’22). Association for Computing Machinery, New York, NY, USA, 1119–1132. https://doi.org/10.1145/3532106.3533543[10] Omid Ettehadi, Lee Jones, and Kate Hartman. 2020. Heart waves: A heart rate
feedback system using water sounds. In Proceedings of the fourteenth international
conference on tangible, embedded, and embodied interaction. 527–532.
[11] Janet K. Gibbs, Marco Gillies, and Xueni Pan. 2022. A comparison of the effectsof haptic and visual feedback on presence in virtual reality. International Journalof Human-Computer Studies 157 (2022), 102717.
[12] Kristina Hook. 2018. Designing with the body: Somaesthetic interaction design.
MIT Press.
[13] Julian Kreimeier, Sebastian Hammer, Daniel Friedmann, Pascal Karg, Clemens
Bühner, Lukas Bankel, and Timo Götzelmann. 2019. Evaluation of different
types of haptic feedback influencing the task-based presence and performance invirtual reality. In Proceedings of the 12th acm international conference on pervasive
technologies related to assistive environments. 289–298.
[14] Mindy F. Levin, Patrice L. Weiss, and Emily A. Keshner. 2015. Emergence of
virtual reality as a tool for upper limb rehabilitation: incorporation of motor
control and motor learning principles. Physical therapy 95, 3 (2015), 415–425.
[15] Leonie F. Loose, Jorge Manuel, Matthias Karst, Laura K. Schmidt, and FlorianBeissner. 2021. Flotation Restricted Environmental Stimulation Therapy for
Chronic Pain: A Randomized Clinical Trial. JAMA network open 4, 5 (2021),
e219627–e219627.
[16] Andrés Lucero and Juha Arrasvuori. 2010. PLEX Cards: a source of inspiration
when designing for playfulness. In Proceedings of the 3rd International Conference
on Fun and Games. 28–37.
[17] Steve Mann, Michael Georgas, and Ryan Janzen. 2006. Water jets as pixels: Water
fountains as both sensors and displays. In Eighth IEEE International Symposium
on Multimedia (ISM’06). IEEE, 766–772.
[18] Steve Mann, Max Lv Hao, and Jeremy Warner. 2018. Virtual reality games insensory deprivation tanks. In 2018 IEEE Games, Entertainment, Media Conference(GEM). IEEE, 1–9.
[19] Steve Mann, Mark Mattson, Steve Hulford, Mark Fox, Kevin Mako, Ryan Janzen,
Maya Burhanpurkar, Simone Browne, Craig Travers, and Robert Thurmond. 2021.
Water-Human-Computer-Interface (WaterHCI): Crossing the borders of computation clothes skin and surface. Proceedings of the 23rd annual Water-HumanComputer Interface Deconference (Ontario Place TeachBeach, Toronto, Ontario,
Canada). Ontario Place TeachBeach, Toronto, Ontario, Canada (2021), 6–35.
[20] Steve Mann, Faraz Sadrzadeh-Afsharazar, Samir Khaki, Zhao Lu, Christina Mann,and Jaden Bhimani. 2022. WaterHCI Part 1: Open Water Monitoring with Realtime
Augmented Reality. In 2022 IEEE International Conference on Signal Processing,Informatics, Communication and Energy Systems (SPICES), Vol. 1. IEEE, 49–54.
[21] Maria F. Montoya, Rakesh Patibanda, Christal Clashing, Sarah Jane Pell, andFlorian’Floyd’ Mueller. 2022. Towards an Initial Understanding of the Design ofPlayful Water Experiences Through Flotation. In Extended Abstracts of the 2022
Annual Symposium on Computer-Human Interaction in Play. 120–126.
[22] David Nanchen. 2018. Resting heart rate: what is normal? , 1048–1049 pages.

Montoya et al.

[23] David Nanchen, Maarten JG Leening, Isabella Locatelli, Jacques Cornuz, Jan A.
Kors, Jan Heeringa, Jaap W. Deckers, Albert Hofman, Oscar H. Franco, and Bruno
H. Ch Stricker. 2013. Resting heart rate and the risk of heart failure in healthy
adults: the Rotterdam Study. Circulation: Heart Failure 6, 3 (2013), 403–410.
[24] Rakesh Patibanda, Florian’Floyd’ Mueller, Matevz Leskovsek, and Jonathan Duckworth. 2017. Life tree: understanding the design of breathing exercise games.
In Proceedings of the annual symposium on computer-human interaction in play.
19–31.
[25] Luis Quintero, John E Muñoz, Jeroen De Mooij, and Michael Gaebler. 2021. ExciteO-Meter: Software Framework to Integrate Heart Activity in Virtual Reality. In
2021 IEEE International Symposium on Mixed and Augmented Reality (ISMAR).
IEEE, 357–366.
[26] Bernd Tessendorf, Franz Gravenhorst, Bert Arnrich, and Gerhard Tröster. 2011.
An imu-based sensor network to continuously monitor rowing technique on
the water. In 2011 seventh international conference on intelligent sensors, sensor
networks and information processing. IEEE, 253–258.