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<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>Corresponding author.
juho.e.mattila@oulu.fi(J. Mattila); thusitha.bandaranayake@oulu.fi(S. Bandaranayake);
prabhash.ekanayakawidanage@student.oulu.fi(P. Rathnayake); pasi.karppinen@vub.be (P. Karppinen)</journal-title>
      </journal-title-group>
    </journal-meta>
    <article-meta>
      <title-group>
        <article-title>Key dimensions in IoT-enabled serious AR games for awareness of indoor air quality and healthy behavior reinforcement: an exploratory case study⋆</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Juho Mattila</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Sameera Bandaranayake</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Prabhash Rathnayake</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Pasi Karppinen</string-name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>University of Oulu</institution>
          ,
          <addr-line>Pentti Kaiteran katu 1, 90570 Oulu</addr-line>
          ,
          <country country="FI">Finland</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Vrije Universiteit Brussel</institution>
          ,
          <addr-line>Bd de la Plaine 2, 1050 Ixelles</addr-line>
          ,
          <country country="BE">Belgium</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2025</year>
      </pub-date>
      <volume>000</volume>
      <fpage>0</fpage>
      <lpage>0003</lpage>
      <abstract>
        <p>This study explores the design and development of serious games using augmented reality (AR) technologies integrated with IoT sensors. The aim is to raise student awareness of air quality in their study environments. The study employed qualitative data gathered from three iterations of game implementations with thematic analysis. Results were classified into four key dimensions: IoT integration and data management, game design and mechanics, user experience and engagement, and educational impact and outcomes. Findings indicate that real-time environmental data can reinforce IAQ awareness and prompt healthier decision-making within a game context, although sustaining user engagement and overcoming technical barriers remain challenges. Moreover, incorporating refined game design elements such as improved feedback loops may enhance both educational impact and motivational appeal.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;serious game</kwd>
        <kwd>IoT</kwd>
        <kwd>AR</kwd>
        <kwd>IoTeSG</kwd>
        <kwd>pervasive gaming</kwd>
        <kwd>game design</kwd>
        <kwd>game development</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>
        Indoor air quality (IAQ) in educational institutions has garnered increasing attention due to its
direct influence on student performance and well-being. Classrooms’ indoor environmental
conditions have been recognized to affect academic achievement among students and teachers in
higher education, highlighting the importance of adequate ventilation, temperature control, and air
filtration measures [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. Various factors have been identified in classrooms such as CO₂ levels and
pollutant concentrations that directly impact student academic performance and overall health [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ].
      </p>
      <p>
        People in both developing and developed countries spend an estimated 80–90% of their time
indoors. Although HVAC systems aim to maintain indoor environmental quality (IEQ), they are
not always effective, and health organizations’ guidelines for IEQ are often only voluntary. Various
pollutants from building materials and occupants contribute to poor IAQ, which can lead to
numerous negative health outcomes. For instance, insufficient air circulation can facilitate the
spread of infectious diseases [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ].
      </p>
      <p>
        Studies on the IEQ of university classrooms revealed that poor indoor air quality, which is
characterized by high levels of CO₂, inadequate ventilation, and other environmental factors, has a
negative impact on students' concentration, productivity, and overall health. The students are at
greater risk because of the long hours they spend in these environments. As a result, improving the
IAQ in classrooms is critical for improving student wellbeing and academic performance [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ].
      </p>
      <p>
        The Internet of Things (IoT) has been developed and implemented over the last decade for
numerous use cases ranging from industry use and many ways it has become a cornerstone of our
digital society [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ]. The concept of IoT is described as a means of creating a novel form of pervasive
technology by incorporating radio-frequency identification and other sensors into ordinary things
[
        <xref ref-type="bibr" rid="ref6">6</xref>
        ]. It has been incorporated into many public and private spaces in the form of smart sensors that
can measure various things, such as movement, light, and air quality [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ].
      </p>
      <p>
        Serious games are digital or mixed-reality experiences that engage players through story and
gameplay to inform or influence [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ]. They have been emphasized having a useful purpose,
otherwise, all virtual games could be considered educational by default [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ].
      </p>
      <p>This research explores the potential of IoT-enabled augmented reality (AR) serious games to
raise student awareness of IAQ and promote healthier behaviors. By integrating real-time IoT
sensor data with AR, we developed the Legend of Alumnus, an interactive game that merges virtual
and physical environments to educate students on the impact of IAQ on their health and behavior.
The primary objective is to design and assess the effectiveness of such games in fostering IAQ
awareness and encouraging behavioral change by motivating students to navigate their campus
toward locations with better air quality. This integration creates an educational experience that
extends beyond the digital screen, reinforcing the importance of IAQ in everyday decisions.</p>
      <sec id="sec-1-1">
        <title>To guide this investigation, we address the following research questions (RQs):</title>
        <p>•
•</p>
        <p>RQ1: How can real-time IAQ sensor data be effectively integrated within an AR game to
enhance students’ awareness of indoor air quality?
RQ2: Which game design features and user experience factors most significantly influence
student engagement and healthy behavior reinforcement in an IoT-enabled AR game aimed
at IAQ awareness?</p>
      </sec>
    </sec>
    <sec id="sec-2">
      <title>2. Background</title>
      <p>
        The scientific community recognizes the potential of serious games in healthcare, particularly
when integrated with IoT-enabled monitoring devices to promote healthy behaviors like physical
exercise. Personalization within these games enhances their effectiveness, with engagement levels
reflecting the success of the healthy behaviors encouraged by the IoT-enabled serious games
(IoTeSGs) [
        <xref ref-type="bibr" rid="ref10 ref11 ref12">10-12</xref>
        ].
      </p>
      <p>
        [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ] explored an IoT-enabled AR exergame that combines virtual and real-world tasks while
leveraging biometric data from wearables and sensors for game adjustments. Although participants
reported improved physical activity and health metrics, the study highlighted the need for more
streamlined interfaces in complex environments. In parallel, [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ]’s investigation of pervasive
mixed-reality games underscores the importance of studying how virtual and physical elements
intersect in player experiences, recommending robust methodologies to better understand and
validate game design choices in mixed-reality contexts. [
        <xref ref-type="bibr" rid="ref15">15</xref>
        ] examined an AR-based serious game
for air quality awareness, using avatars that change appearance based on real-time data. User
feedback noted the game’s educational and entertainment value but suggested design
improvements for simplicity and intuitiveness. The study underscores AR and IoT as effective in
representing data interactively, though immersive aspects need further exploration.
      </p>
      <p>
        [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ] proposed a conceptual model for user engagement in mobile-based AR games identifying
clear goals, satisfaction, challenge, focused attention, perceived usability, interaction, social
elements, and mixed fantasy as key drivers of user engagement, aligning with [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ], who stress the
importance of well-defined objectives, rewards, and regular feedback in fostering intrinsic
motivation, while appealing aesthetics can evoke emotional engagement and encourage players to
ignore external distractions.  Additionally, studies show that familiarity with real-world settings
can reduce fatigue in location-based AR games, while newcomers often experience higher
immersion, sometimes even struggling to reorient to reality [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ]. AR features in location-based
games have been found often undervalued due to slow responsiveness. However, integrating Points
of Interest (PoI) with real-world context or history makes gameplay more meaningful and
motivating, while representing real-world objects on in-game maps effectively bridges the gap
between physical and virtual environments [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ]. Brand appeal, social interaction, and progression
systems (e.g., collecting items, leveling up) can sustain long-term interest in AR games like
Pokémon GO; conversely, technical issues and repetitive progression lead to disengagement [
        <xref ref-type="bibr" rid="ref20">20</xref>
        ].
From a technical standpoint, IoT-enabled serious games require robust architectures, security
measures, standardized data management, hardware considerations, and reliable connectivity [
        <xref ref-type="bibr" rid="ref21">21</xref>
        ].
For instance, MQTT can efficiently transfer sensor data, but data structure consistency and
authentication are essential for scalability.
      </p>
    </sec>
    <sec id="sec-3">
      <title>3. Methodology</title>
      <p>
        This study adopts an exploratory case study design as outlined by Yin [
        <xref ref-type="bibr" rid="ref22">22</xref>
        ] to investigate how an
IoT-enabled serious game can raise student awareness of indoor air quality. Exploratory case
studies are especially suitable for examining novel or not yet fully understood phenomena, which
in this case involves integrating real-time IoT sensor data with AR mechanics. Such a design
offers flexibility in uncovering emergent patterns and evolving relationships
among gameplay, sensor data, and user engagement, particularly when the boundaries between the
research context and the phenomenon are unclear.
      </p>
      <sec id="sec-3-1">
        <title>3.1. Iterative development process</title>
        <p>This section presents the Legend of Alumnus game, its three iterations, their game design, why
certain design aspects or principles were selected, and how these were implemented in conjunction
with the IAQ sensor data. The game utilizes both AR game and IoTeSG design paradigms. The
purpose of the game is to explore new ways to utilize IoT sensors so they can purposefully affect
the gameplay mechanics. The project spanned from 2022 to 2024, over three iterations, with
separate student groups from the Research &amp; Development project course in Information
Processing Science at the University of Oulu. Throughout the process, the researcher and product
owner guided the design and development to ensure that the outcomes were meaningful for
research into IoT sensor and AR usage in games.</p>
        <p>The initial concept of the game, presented to the student groups, involved creating a game
based on university mythology, incorporating location-based gameplay and AR, while leveraging
the smart campus IAQ sensor network that had been implemented throughout the campus.
Although the concept and certain project requirements were part of the assignment, the student
groups were given the freedom to design the game and its mechanics as they saw fit.</p>
        <p>The game development followed an iterative design process across three distinct versions. The
iterations are summarized in Table 1, which provides an overview of each version’s platform,
genre, game loop, and the integration of IoT sensor data and location-based mechanics. Figure 1
presents the user interfaces of each iteration. Each iteration focused on improving specific aspects
of the game, such as IoT sensor data integration, location-based mechanics, and gameplay
progression.</p>
      </sec>
      <sec id="sec-3-2">
        <title>3.1.1. First iteration</title>
        <p>The initial prototype of Legend of Alumnus was developed as a location-based AR action
roleplaying game (RPG) for Android. Players navigated the campus physically, encountering ghosts
spawning near IAQ sensor locations. Due to integration challenges, historical IAQ data was used,
with ghost spawn rates linked to local IAQ levels. The game featured a 3D campus map, and ghost
encounters led to AR battles where players shot ghosts to reduce their health until capture. An
inventory provided capture aids, and a ghost database allowed players to collect and track different
ghost types. In this first iteration, testing was conducted exclusively within the development team
and the project’s customer company. The primary focus was on ensuring the game’s basic
functionality and testing the initial integration of historical air quality data with the game
mechanics. At this stage, the emphasis was placed on identifying technical challenges, resolving
gameplay issues, and improving the integration of IAQ data. No formal usability tests were
conducted during this phase, as the game was still in an early prototype stage.</p>
      </sec>
      <sec id="sec-3-3">
        <title>3.1.2. Second iteration</title>
        <p>The second prototype took a different approach in its game design. While the first prototype
concentrated on AR-style gameplay with location-based mechanics, the second iteration presented
a classic RPG design and gameplay, where smart campus sensors influenced the strength of
enemies appearing on the game map. There was no player location integration, and the player
navigated the pixel-style university map using a keyboard and mouse on PC. In this iteration, the
game loop consisted of the player navigating the game world, following a storyline, and collecting
items, such as keys, to progress. When encountering ghosts, a turn-based battle scene would start,
where the player had options to attack, defend, heal, or wait. Additionally, the game included a
subsidiary loop in which the player earned rewards and experience points (XP) to level up.</p>
        <p>
          The second iteration of the game introduced a structured evaluation, applying a heuristic
evaluation framework based on [
          <xref ref-type="bibr" rid="ref23">23</xref>
          ]'s Heuristic Evaluation of Playability. This internal assessment
with five test users focused on playability and usability, evaluating the interface, navigation, and
gameplay mechanics. Key heuristics included ease of use, player motivation, rule clarity, and
effective integration of IoT sensor data. Conducted by the development team, the evaluation aimed
to identify usability and gameplay issues, refining mechanics, UI, and the use of real-time IoT data,
such as adjusting enemy strength based on environmental factors like CO₂, motion, temperature,
and light.
        </p>
      </sec>
      <sec id="sec-3-4">
        <title>3.1.3. Third iteration</title>
        <p>The third iteration took a more serious turn; while the game design of the two first iterations
concentrated on creating a fun and engaging experience of playing a game revolving around the
campus, in third iteration, the IAQ on campus and how it affects the health of students was in
center of attention. The core design aimed to encourage students to avoid areas with poor air
quality, particularly where CO2 levels exceeded a certain threshold.</p>
        <p>The game genre remained location-based AR game, but it incorporated strong design elements
from contemporary idle games. The main game loop involved the player navigating the campus
and selecting study locations based on IAQ information provided by the game. Players were tasked
with placing a virtual pet-style spirit companion in areas with good air quality. To nurture their
spirit companion, the player had to periodically relocate the spirit to maintain its health in good
IAQ zones. If left in a bad IAQ area for too long, the spirit would become sick, reducing the player’s
ability to earn Intellectual Points (XP).</p>
        <p>While the player was idle, they could occasionally feed the spirit with resources collected from
specific locations on campus. In addition, players were periodically awarded with spirit evolutions,
adding another layer of gameplay complexity through a secondary loop.</p>
        <p>
          In this final iteration usability testing was conducted using an Android test APK, involving both
internal team members (e.g., four student developers) and external volunteers (four test users) with
diverse backgrounds in technology and gaming. Following best practices in usability research by
[
          <xref ref-type="bibr" rid="ref24">24</xref>
          ], each participant was guided through six tasks: (1) navigating to a specified location using the
in-game map, (2) placing the spirit in high-IAQ areas, (3) evolving the spirit companion, (4)
collecting and feeding resources, (5) responding to high CO₂ alerts, and (6) freely exploring the AR
environment thereby evaluating key game mechanics, real-time IoT sensor data integration, and
educational effectiveness. After completing these tasks, participants filled out a questionnaire
assessing navigation clarity, system performance, perceived educational value, and overall
engagement.
        </p>
      </sec>
      <sec id="sec-3-5">
        <title>3.2. Data collection</title>
        <p>At the end of each iteration, developer experiences were systematically collected and documented
through various project artifacts and reports. These included game design documents, expertise
reports, project plans, steering group meeting minutes, mid- and final reports, project portfolios,
seminar papers, PowerPoint presentations, Unity game project scripts, communiques between the
project team and the customer, game evaluation reports, and the game builds for both Android and
Windows platforms. This comprehensive set of documentation captured the development process,
challenges encountered, decisions made, and the outcomes of each iteration. Alongside user
feedback from the testing phases, these materials served as the primary data for analysis.</p>
      </sec>
      <sec id="sec-3-6">
        <title>3.3. Analysis</title>
        <p>
          The data collected from these artifacts were analyzed using Braun and Clarke’s thematic analysis
method [
          <xref ref-type="bibr" rid="ref25">25</xref>
          ], which provided a structured approach to identifying patterns or themes across the
iterations. As outlined in Table 2, thematic analysis was conducted in five steps to ensure a
thorough examination of the design and development, as well as the educational impact of the
game.
        </p>
        <p>The first phase was a thorough examination of all the relevant documentation and artifacts of
the three iterations of the project. Straight from the data, inductive reasoning was used to extract
evidence patterns and insights.</p>
        <p>The evidence was then categorized under key aspects of game development. To ensure that the
coding was limited to evidence that contributed to unique insights, this stage required filtering out
common knowledge components to concentrate on material that could yield new understandings.
Abductive reasoning was used.</p>
        <p>Then, similar bits of data were grouped into coherent categories to uncover first-order themes.
Inductive reasoning was used to combine cohesive themes from related evidence. After that,
second-order themes and aggregate dimensions were created by further abstracting and
synthesizing first-order themes for structured and comprehensive analysis of the qualitative data.
In this stage, inductive reasoning was still used.</p>
        <p>In the final step, the underlying core causes and effects of each aggregate dimension were
investigated. This step involved connecting the aggregate dimensions with reasoning and evidence
from literature. The goal was to confirm the findings by connecting the aggregate dimensions to
existing theoretical frameworks, utilizing abductive reasoning to ensure robustness.</p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>4. Results</title>
      <p>This chapter presents the key results of the thematic analysis, which are organized into four
primary aggregate dimensions: IoT integration and data management, game design and mechanics,
user experience and engagement, and educational impact and outcomes. Figure 2 presents the key
thematic dimensions identified in the analysis.</p>
      <sec id="sec-4-1">
        <title>Identification of data sources with empirical evidence for the project objectives</title>
      </sec>
      <sec id="sec-4-2">
        <title>Classification of the evidence under all the key aspects of game development</title>
      </sec>
      <sec id="sec-4-3">
        <title>Filter common knowledge elements to ensure coding focuses on evidence that can generate new understandings</title>
      </sec>
      <sec id="sec-4-4">
        <title>Identify first-order themes</title>
      </sec>
      <sec id="sec-4-5">
        <title>Identify second-order themes and aggregate dimensions</title>
      </sec>
      <sec id="sec-4-6">
        <title>Analyzing core causes and effects of each aggregate dimension</title>
      </sec>
      <sec id="sec-4-7">
        <title>Combine related evidence into cohesive themes</title>
      </sec>
      <sec id="sec-4-8">
        <title>Further abstraction and synthesis of the first-order themes for structured and comprehensive analysis of qualitative data</title>
      </sec>
      <sec id="sec-4-9">
        <title>Connect aggregate dimensions with reasoning and evidence from the literature to confirm the findings</title>
        <p>Methodological
approach</p>
      </sec>
      <sec id="sec-4-10">
        <title>Inductive</title>
      </sec>
      <sec id="sec-4-11">
        <title>Abductive</title>
      </sec>
      <sec id="sec-4-12">
        <title>Inductive</title>
      </sec>
      <sec id="sec-4-13">
        <title>Inductive</title>
      </sec>
      <sec id="sec-4-14">
        <title>Abductive reasoning</title>
        <sec id="sec-4-14-1">
          <title>4.1. IoT integration and data management</title>
          <p>Effective integration and management of IoT sensor data played a crucial role in the game's
development and functionality. The reliability and accessibility of data were central to ensuring
that the game could dynamically respond to real-world conditions, and several critical factors were
identified in the process.</p>
          <p>Data accessibility and reliability emerged as one of the key components for successful
implementation. The use of persistent flags within the MQTT broker was instrumental in
maintaining data reliability, particularly when sensor updates were infrequent. These flags allowed
the system to preserve the most recent data, ensuring that even when the sensors weren’t
continuously sending updates, the game could still access reliable, up-to-date information. The
inclusion of these persistent flags mitigated potential data losses and allowed for smoother game
performance</p>
          <p>Another key finding in this area involved the structure of the data itself. Initially, all devices
were publishing sensor data under a single topic within the MQTT broker, which created
significant bottlenecks during game initialization. The lack of a structured, atomized approach
meant that the system had to process a large volume of irrelevant data, causing delays in loading
the game levels. This inefficiency was addressed by restructuring the MQTT broker to publish data
in separate topics, allowing the game to initialize much faster. Furthermore, atomizing the data
structure, combined with persistent flags, proved to be highly effective in enhancing data
management.</p>
          <p>Despite these improvements, real-time data access remained a challenging aspect of the
development process. The MQTT broker lacked the capability to specifically target the most
relevant sensors, which presented difficulties when the game needed to fetch real-time data for
dynamic game mechanics. This issue was particularly noticeable during the third iteration, where
the game struggled to fetch only the latest sensor readings. Consequently, the project team
implemented a solution that relied on historical data retrieved through the smart campus REST API
to expedite the initialization process. While this workaround helped resolve initialization delays, it
also highlighted the limitations of the MQTT broker's real-time data handling capabilities. </p>
          <p>The use of Unity game objects to fetch real-time data directly from the MQTT broker further
optimized the gameplay experience. The Unity game objects were specifically designed to handle
the real-time sensor data that influenced various aspects of the game, such as updating enemy
power levels and affecting quest outcomes. By integrating live environmental data into the game
mechanics, the game could mirror real-world conditions in real time, creating a more immersive
and responsive experience for the players. However, the inability to consistently retrieve only the
latest sensor readings meant that in some cases, game initialization was slower than desired,
particularly when dealing with a large number of sensors.</p>
        </sec>
        <sec id="sec-4-14-2">
          <title>4.2. Game design and mechanics</title>
          <p>The design and mechanics of the game evolved through iterations, with a consistent focus on
integrating real-world data into the virtual environment, aiming to enhance player engagement,
and refining gameplay elements based on sensor inputs. Each aspect of the game’s design was
shaped by the need to mirror real-world conditions, allowing players to interact with both their
physical and virtual surroundings.</p>
          <p>One of the defining features of the game was its use of real-world air quality data to influence
in-game mechanics. Throughout the iterations, players were required to physically move within
the game’s environment to seek out areas with better air quality, which would provide in-game
incentives. This was particularly evident in the third iteration, where players had to place virtual
pets in locations with favorable air quality to ensure their pets thrived. The University of Oulu
campus was recreated virtually, and the game’s mechanics were designed to reflect live sensor data
from this real-world location.</p>
          <p>This approach was not just about providing players with information but about integrating it
seamlessly into the gameplay. The player's real-world position was mirrored within the virtual
world, ensuring that decisions made in the game were influenced by real-time conditions. For
example, players could not place their virtual pets in locations that were far from their actual
physical position, further emphasizing the link between the virtual and physical worlds. Sensor
data thus became a critical gameplay element, informing where pets could be placed and how they
interacted with the environment.</p>
          <p>Another key feature of the game was the use of dynamic game elements, driven by real-time air
quality data. The game used the classification of air quality, particularly CO2 levels, to generate
passive points for the player’s virtual pets. Each sensor in the real world corresponded to a specific
area in the virtual game world, and the CO2 levels from these sensors determined how the
environment within that area would behave. For instance, areas with poor air quality would result
in fewer rewards for the player, while areas with better air quality would provide additional points
and benefits. This dynamic interaction between real-world environmental data and in-game
mechanics added complexity to the gameplay, as players were encouraged to make strategic
decisions based on real-time data.</p>
          <p>In addition to influencing passive point generation, environmental data also shaped the
behavior and characteristics of in-game enemies. The number, size, and power levels of enemies in
the game were directly linked to the environmental data captured by specific sensors. In the first
and second iterations, the strength of enemies and their spawning rates were tied to air quality
levels, with tougher enemies appearing in areas with poorer environmental conditions. This added
a layer of challenge to the game, as players had to factor in real-world environmental factors when
planning their movements and strategies.</p>
          <p>The iterative design process allowed for continuous refinement of the game’s user interface (UI)
and interaction elements. The development team adopted a multi-stage prototyping approach,
starting with low-fidelity sketches and wireframes to test basic functionalities. These early designs
provided a foundation for high-fidelity prototypes that were later developed in tools such as Figma,
which enabled the team to fine-tune the aesthetic and functional aspects of the game.</p>
          <p>A key focus during this iterative process was ensuring that the game’s UI could adapt flexibly to
meet both aesthetic and functional demands. By working through multiple stages of prototyping,
the team was able to refine the user experience, improving both the visual appeal and the usability
of the game. The placeholders used in early iterations allowed for the testing of features and
scaling requirements, ensuring that the final design could handle the complex interactions between
real-world data and virtual game elements.</p>
          <p>Another important aspect of the iteration process was the use of generative AI to fill gaps in art
and asset creation. The team faced challenges in creating game assets that fit the selected themes
due to limited resources and skills in art and design. To overcome this, they employed generative
AI, which allowed them to produce better quality assets. While the lack of existing protocols or
guidelines for using generative AI in game development was an initial barrier, the approach proved
to be successful for the project outcomes in the second iteration where generative AI was used.</p>
        </sec>
        <sec id="sec-4-14-3">
          <title>4.3. User experience and engagement</title>
          <p>User experience and engagement in the game were evaluated through testing and feedback in the
third iteration. Key insights revealed issues with player motivation, navigation, interaction,
immersion, and accessibility. A primary challenge was the low engagement with the game’s
environmental goals. The virtual pet system, involving pet care and point rewards, lacked strong
incentives to keep players interested. The pets’ health and points linked to air quality were not
compelling enough, leading to reduced player motivation to engage with environmental aspects
like air quality monitoring or real-world actions based on in-game data.</p>
          <p>The usability testing also highlighted several issues with navigation and interaction within the
game. Although the app's basic navigation was generally perceived as simple, users expressed a
need for clearer and more intuitive navigational aids. For example, participants found it difficult to
distinguish player pins and virtual pet locations on the map, which affected their ability to interact
smoothly with the game world. This confusion indicated that the UI needed further refinement,
particularly in terms of its icons and map elements.</p>
          <p>Furthermore, some users struggled to complete tasks related to collecting points or interacting
with specific game features, pointing to gaps in the clarity of the game’s instructions. The need for
more explicit, in-game guidance was evident, as players often found themselves uncertain about
the steps required to progress or complete certain tasks. These findings suggested that better UI
enhancements and clearer instructions were crucial to improving the overall player experience.</p>
          <p>The game’s design prioritized immersion and accessibility, using real-world data integration to
boost player engagement. Real-time interactions between the virtual and physical worlds created a
strong immersive effect, helping players feel connected to both. This feature, which linked
realtime data to in-game outcomes, was well-received, supporting the game’s educational and
environmental goals. However, some technical issues slightly impacted the overall immersion.</p>
          <p>One significant issue was the game's use of GPS for indoor location tracking, which resulted in
inaccurate measurements. The initial implementation of the location service API in the Unity
engine defaulted to GPS, which is generally ill-suited for indoor environments due to
non-line-ofsight (NLOS) conditions. These conditions led to inaccurate tracking, further compounded by the
Unity API’s insufficient documentation on indoor location tracking. Since the gameplay
environment was entirely indoors, these challenges had a considerable impact on the user
experience.</p>
          <p>To address these issues, the development team implemented network-based localization
techniques, which significantly improved the accuracy of indoor tracking. This solution helped
bring the location tracking to an acceptable level, making the game more responsive and enhancing
the immersive experience for the players. In addition, the game’s use of standard gestures, such as
pinching and zooming, contributed to a more intuitive gameplay experience, ensuring that players
could interact with the virtual environment in a familiar and accessible manner.</p>
        </sec>
        <sec id="sec-4-14-4">
          <title>4.4. Educational impact and outcomes</title>
          <p>The game's design was aiming to encourage healthier behaviors and provide informal learning
opportunities related to indoor air quality.</p>
          <p>One of the main goals of the game was to promote behavioral change by motivating players to
spend more time in environments with better air quality, thereby encouraging healthier habits.
Players were required to be physically present on campus to progress in the game (in first and third
iterations), tying real-world movement and location to game rewards. This requirement was seen
as motivating to stay in campus for longer periods and encouraging to stay in areas with better
IAQ.</p>
          <p>The use of virtual pets in the third iteration served as a key mechanism for reinforcing these
behaviors. Players were encouraged to place their virtual pets in locations with good IAQ, as poor
air quality would negatively affect the pets’ health, causing them to devolve. This negative
reinforcement mirrored real-world consequences and pushed players to seek out healthier
environments, thus integrating the educational goal of raising awareness about the importance of
IAQ. The design also included notifications as reminders to take breaks or move to better air
quality locations.</p>
          <p>The effectiveness of these behavioral cues was enhanced by the lack of a need for continuous
active tracking. Players did not need to monitor the game constantly; rather, periodic interactions
with their virtual pets acted as brief study breaks and moments to reflect on the indoor
environment, subtly encouraging behavioral change without overwhelming the player.</p>
          <p>In addition to promoting behavioral change, the game fostered informal learning about indoor
air quality through its use of real-time data and interactive UI elements. The game’s interface
displayed IAQ information in a way that was directly linked to the player's environment, allowing
them to see how air quality affected their virtual pets and overall game progression. User feedback
from the questionnaire, however, revealed mixed understanding of the app's purpose and
mechanics, suggesting a gap in clear communication. Moreover, motivation to engage with the
game's environmental goals was generally low, underscoring a need for better incentives and
improved feedback loop.</p>
          <p>The inclusion of notifications contributed to the informal learning process. Reminders to check
on virtual pets after closing the app served as gentle prompts, encouraging players to reflect on air
quality and its importance. These notifications were designed to trigger with a delay, ensuring that
players remained engaged with the game’s educational goals even during periods of inactivity. The
periodic check-ins with virtual pets acted as a tool for reinforcing the knowledge that better air
quality leads to more positive in-game outcomes, indirectly teaching players the value of
maintaining healthier environments in real life. However, malfunctioning CO₂-level alerts and
other notifications, which are crucial for enhancing gameplay engagement and the educational use
of real-time data, were significant issues, with participants expressing a desire for a fully functional
notification system to better support both gameplay and educational objectives.</p>
        </sec>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>5. Discussion</title>
      <p>The study contributes to the field of IoT-enabled serious AR game development in four key aspects:
IoT integration and data management, game design and mechanics, user experience and
engagement, and educational impacts and outcomes.</p>
      <p>
        The IoT integration and data management aspects include accessibility and reliability, data
structure, and real-time data access. Data accessibility and reliability were critical, with persistent
flags in MQTT broker publish events enhancing reliability when updates were infrequent. Efficient
data management required an atomized data structure and separate MQTT server topics for device
data, enabling faster game level initialization. [
        <xref ref-type="bibr" rid="ref21">21</xref>
        ] emphasized the importance of data
preprocessing and normalization for uniformity, a finding our study extends by detailing practical
implementations. It has been pointed out that IoT-enabled serious gaming with AR is an enhanced
interactive technique to present digital data in the real world [
        <xref ref-type="bibr" rid="ref15">15</xref>
        ]. The study explored practical
avenues for achieving this with utilization of game objects for fetching the real-time data from
broker, capability of targeting individual sensors in MQTT broker and capability to fetch only the
latest sensor reading. These aspects contribute to reflecting real world conditions via game
mechanics operated in real time.
      </p>
      <p>
        The game design and mechanics include three core aspects: real-world integration, dynamic
game elements, and prototyping with iteration. Real-world integration involves three key elements:
sensor data reflecting real-world conditions to inform and impact the virtual environment, live data
integration to create a mirrored, hybrid interaction space, and game rules based on player
proximity, allowing interaction with real-world locations. Integrating real-world elements into AR
objects creates a unique experience in AR gaming, though seamlessly blending virtual and physical
content remains challenging [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ]. These insights offer practical solutions, enhancing immersion
and user experience by fostering familiarity and reducing cognitive load [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ]. Dynamic game
elements focus on using environmental sensor data to shape incentives and challenges based on
each location’s conditions. Successful prototyping and iteration were impacted by three factors:
flexible UI adaptation for aesthetic and functional needs across prototyping stages, smooth
transitions between fidelity levels for in-depth exploration of interactive elements and using
placeholder maps to test and scale features. Generative AI supported asset creation, addressing skill
gaps in the development team. Aesthetic design improved navigation and enhanced emotional
engagement through visual and audio elements [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ]. These findings support a multi-fidelity
prototyping approach and the integration of generative AI in design.
      </p>
      <p>
        Three main components were identified in user experience and engagement: motivation and
retention, navigation and interaction, and immersion and accessibility. Findings showed that key
factors for motivation and retention included faster game responsiveness and well-designed
incentives, aligning with literature linking engagement to progression and diverse rewards [
        <xref ref-type="bibr" rid="ref20">20</xref>
        ].
Studies also suggest users devalue AR when responsiveness lags [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ]. Notifications reinforced
realworld activities, aiding player retention. Effective navigation involved panning, zooming, and clear
in-game instructions, while immersion and accessibility benefited from real-world data integration,
standard gestures, intuitive gameplay, and accurate location tracking, with GPS proving ineffective
indoors.
      </p>
      <p>
        The educational impact of IoT-enabled serious AR games was observed in two areas: behavioral
change and informal learning. Real-time data interactions through notifications and UI elements
supported informal learning about indoor environmental conditions, aligning with research
showing that AR-based avatars enhance educational outcomes by combining learning with
entertainment [
        <xref ref-type="bibr" rid="ref15">15</xref>
        ]. Studies also highlight the effectiveness of IoT-enabled games in promoting
healthy behaviors by monitoring environmental and user data [
        <xref ref-type="bibr" rid="ref12 ref13">12, 13</xref>
        ]. The game mechanics used
notifications to reinforce healthy behavior and encourage users to be present in specific locations
as intended by design.
      </p>
      <p>However, usability tests of the third iteration identified technical and pedagogical challenges.
Participants found navigation manageable but requested clearer map icons and instructions.
Technical issues, such as slow responsiveness, hindered immersion and sensor data integration,
reducing both engagement and IAQ awareness. Additionally, the game emphasized recognizing
poor air quality over providing actionable steps, highlighting the need for more behavior-oriented
design elements.</p>
    </sec>
    <sec id="sec-6">
      <title>6. Conclusion</title>
      <p>
        This study explored the design and development of IoT-enabled serious games using AR
technologies to raise student awareness of IAQ and promote healthy behaviors. Utilizing data from
three iterative implementations and applying Braun and Clarke's thematic analysis [
        <xref ref-type="bibr" rid="ref25">25</xref>
        ], four key
dimensions were identified: IoT integration and data management, game design and mechanics,
user experience and engagement, and educational impact and outcomes. The findings demonstrate
the potential of such games to drive behavioral change and enhance user engagement while
highlighting the necessity of overcoming technical barriers and refining educational content. By
effectively integrating IoT data with AR mechanics, this study offers practical guidance for
designing and implementing gamified applications. It underscores the importance of robust data
management, dynamic game design, and user-centered interactions in creating immersive
educational experiences that raise awareness and encourage meaningful behavior change in
realworld environments. These contributions advance both theoretical understanding and practical
applications in the field of IoT-enabled serious games.
      </p>
    </sec>
    <sec id="sec-7">
      <title>7. Limitations and future work</title>
      <p>One significant limitation of this project was the initial lack of clarity in objectives. The original
idea was simply to create a game that incorporated real-life data into its game mechanics, without
a well-defined long-term vision or rigorous methodology. As the project progressed, the concept
was gradually refined through iterative development, but the process lacked a structured approach.
Consequently, the collection and categorization of research data were inconsistent. Future research
must create explicit theoretical and practical foundations for the usage of IoT sensors in games.
Integrating established game design principles with IoT sensor technology will result in a more
structured and focused approach to IoT-enabled serious game design and development. This will
ensure that future initiatives accomplish their aims and provide vital insights on how to effectively
integrate IoT technology into educational and environmental awareness games. The practical
application of generative AI throughout various stages of the game development process represents
a promising area for future research. This technology empowers developers with limited resources
or skills to design impactful games more efficiently and creatively.</p>
    </sec>
    <sec id="sec-8">
      <title>Acknowledgements</title>
      <p>The research and development during the second iteration were supported by The Finnish
Information Processing Association (TIVIA) and Tietotekniikan tutkimussäätiö in 2022, along with
the Metapilot Factory project funded by the Joint Task Force (JTF) for the main author in 2024. The
second author received funding from the Infotech Emerging Project under the University of Oulu.</p>
      <p>We extend special thanks to the student groups. The first group included Joni Kilpeläinen, Juuso
Laivamaa, Bashir Kasozi, and Miko Korhonen; the second group, Renata Moilanen, Janne
Mourujärvi, Heikki Kallankari, Tommi Lämsä, and Amine Zeggaf; and the third group, Emma
Kemppainen, Jere Pesälä, Iiso Kramsu, and Juho Seinijoki. Their dedication in creating the designs
and technical prototypes, along with their background research, was crucial to the project’s
success.</p>
      <p>We extend our sincere gratitude to the Smart Campus organization at the University of Oulu for
their support with sensor data integration. Finally, we thank Ikune Labs for providing the research
case.</p>
    </sec>
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