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  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>[2] Praveen Borra (2024). An overview of Cloud Computing and Leading Cloud Service Providers.
International Journal of Computer Engineering and Technology</journal-title>
      </journal-title-group>
    </journal-meta>
    <article-meta>
      <article-id pub-id-type="doi">10.17605/OSF.IO/5HQ4M</article-id>
      <title-group>
        <article-title>Simplify the creation of remote controls and monitoring interfaces for microcontrollers and automation systems using IoT Cloud services</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Filippos Kladouchas</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Nikitas N. Karanikolas</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>University Of West Attica</institution>
          ,
          <addr-line>Ag. Spyridonos street 12243 Egaleo</addr-line>
          ,
          <country country="GR">Greece</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2024</year>
      </pub-date>
      <volume>15</volume>
      <issue>3</issue>
      <fpage>0000</fpage>
      <lpage>0003</lpage>
      <abstract>
        <p>Usually, remote controls of automation systems or electronic devices is based on infrared radiation. Microcontroller based automation systems can be further controlled by laptops, tablets and smart phones with the help of the local Wi-Fi and HTTP Requests services running on the automation's microcontroller. For extending further the distance of the controlling device, out of the range of the local Wi-Fi of the automation system, some extra machine (usually computer) is needed for hosting some Web Server that communicates (on one hand) through the internet with the controlling device and communicates (on another hand) with the microcontroller with the local WiFi. Consequently, we have more complicated systems that demand more infrastructures and can cause troubles. In this study, we have investigated the possibility to decrease the complexity of controlling automation systems with the IoT Cloud. Our research shows that the existing technology together with the IoT Cloud can make possible the far-away control of Microcontroller based automation systems without the complexity of an extra machine (computer) and an extra Web Server. The relevant IoT Cloud services and the alternative solutions are discussed. Further, a prototype system is also described. The positive and negative conclusions are presented.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;IoT</kwd>
        <kwd>Microcontrollers</kwd>
        <kwd>Home Security</kwd>
        <kwd>IoT Cloud1</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>
        A microcontroller is a compact, low-power integrated circuit designed to perform dedicated control
tasks in embedded systems [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. With built-in
memory, processing, and I/O capabilities,
microcontrollers such as Arduino [9], ESP8266 [6], and ESP32 [7] are widely used in automation.
Their programmability and modularity allow developers to create flexible and customized solutions
for home, industrial, and agricultural applications. Open-source ecosystems further support this
adaptability.
      </p>
      <p>Cloud computing, as described in [2], delivers scalable computing resources via the internet,
eliminating the need for locally managed infrastructure. In automation, it enables seamless remote
access, real-time data processing, and on-demand resource allocation.</p>
      <p>IoT</p>
      <p>Cloud platforms—purpose-built for Internet of Things applications—combine cloud
computing with embedded control [3, 4]. Services like Arduino IoT Cloud [8] and Blynk [17] simplify
device integration, remote management, and dashboard creation by abstracting networking and
server complexity.</p>
      <p>Microcontroller connectivity is enhanced through communication modules such as Wi-Fi (e.g.,
ESP8266), GSM [11], and Bluetooth. These extend access to remote networks or local devices, making
automation more scalable and responsive.</p>
      <p>This paper explores our conjecture that IoT Cloud services can simplify remote control and
monitoring for microcontroller-based automation systems. By removing the need for an on-site
server, such platforms reduce cost and complexity while improving system reliability. We compare
traditional and cloud-based approaches and present a case study in home security to evaluate the
proposed solution’s effectiveness.</p>
    </sec>
    <sec id="sec-2">
      <title>2. Αutomation systems</title>
      <p>For each automation scenario presented, this chapter explores and compares three distinct
implementation approaches: a from-scratch solution, a commercial off-the-shelf solution, and the
proposed custom IoT Cloud-based approach, which is characterized by minimal coding effort and
low hardware complexity.</p>
      <sec id="sec-2-1">
        <title>2.1. Smart Lighting Automation</title>
        <p>Smart lighting systems offer remote and automated control of lights using communication protocols
such as Wi-Fi, Zigbee [21], Bluetooth, and cloud technologies. They allow users to adjust brightness,
set schedules, and integrate lighting into broader home automation systems.</p>
      </sec>
      <sec id="sec-2-2">
        <title>2.1.1. From Scratch – Local Server-Based – Approach for Lighting</title>
        <p>In a from-scratch approach, a microcontroller like Arduino [9, 10, 15] connects to lighting
components (e.g., relays, LEDs) and communicates with a local server (PC or Raspberry Pi) via
WiFi or Ethernet. The server, running software such as Apache, Flask, or Node.js, hosts a dashboard
accessible through a browser or mobile app. When the user sends a command, the server relays it to
the microcontroller using HTTP [22] or MQTT [13, 23, 24], which then controls the lighting
devices.</p>
        <p>This architecture offers full control and data privacy, without relying on third-party platforms.
However, it requires a continuously running local server, increasing energy use and maintenance
demands. Initial setup is complex and hardware-intensive, and remote access is restricted unless
additional configurations like VPN [25] or port forwarding [26] are implemented.</p>
        <p>To enable remote access, users typically configure port forwarding to direct incoming traffic to
the server’s local IP. Though easy to implement, it can introduce security vulnerabilities.
Alternatively, VPNs provide secure, encrypted access by placing the user virtually within the local
network. VPNs are generally considered safer for sensitive applications. Both methods are viable,
but VPNs offer superior privacy and control.</p>
      </sec>
      <sec id="sec-2-3">
        <title>2.1.2. Commercial IoT Cloud-Based Solutions for Lighting</title>
        <p>Commercial smart lighting solutions typically rely on proprietary IoT cloud platforms for
automation and remote access. Devices connect directly to the manufacturer’s cloud using Wi-Fi or
Zigbee, and users manage them via mobile apps or voice assistants like Alexa [27], Google Assistant
[28], or Apple HomeKit [29]. The cloud handles command processing and sends instructions to the
lighting devices.</p>
        <p>This plug-and-play model requires no advanced network setup and provides seamless remote
access. However, it operates within closed ecosystems, limiting customization. Additionally,
functionality depends entirely on the provider's cloud infrastructure; service discontinuation could
render devices unusable. These solutions are generally more expensive than DIY alternatives.
This approach uses platforms like Arduino IoT Cloud [8], Blynk [17], or Firebase [16] to implement
a customizable and scalable smart lighting system. A microcontroller (e.g., ESP8266, ESP32, or
Arduino) connects to lighting components and communicates directly with the cloud, which handles
automation rules, real-time data exchange, and remote access. Users control the system via a mobile
app or web dashboard linked to the cloud service.</p>
        <p>The solution eliminates the need for a local server, lowering hardware and maintenance costs. It
offers greater flexibility than commercial products, allowing full customization at a lower price.
While some setup and coding are required, development is simplified through prebuilt dashboards
and APIs. Free-tier cloud services may impose device or data limits, but the approach remains
costeffective and suitable for personalized automation systems.</p>
      </sec>
      <sec id="sec-2-4">
        <title>2.2. Smart Irrigation Automation</title>
        <p>A smart irrigation system is designed to automatically manage water usage in agricultural or garden
environments, optimizing water consumption while ensuring plants receive adequate moisture.
These systems often use sensors (such as soil moisture sensors) to collect real-time data, and utilize
microcontrollers and communication technologies (Wi-Fi, Zigbee, Bluetooth) to control irrigation
valves or pumps.</p>
      </sec>
      <sec id="sec-2-5">
        <title>2.2.1. From Scratch – Local Server-Based – Approach for Irrigation</title>
        <p>The microcontroller (e.g., Arduino, ESP32, or Raspberry Pi) collects real-time soil moisture data from
soil moisture sensors and controls water pumps or solenoid valves. The local web server (running
Flask, Node.js, or Apache) processes user commands and automation rules. Users access the system
via a local interface to send HTTP requests for manual or scheduled irrigation. Operating entirely
within the local network, this setup guarantees full data privacy, zero cloud reliance, and full
customization. However, it requires a 24/7 running server, complex network setup, and port
forwarding or VPN for remote access. Additionally, power consumption is higher due to continuous
operation of the local host.</p>
      </sec>
      <sec id="sec-2-6">
        <title>2.2.2. Commercial IoT Cloud-Based Solutions for Irrigation</title>
        <p>Commercial irrigation controllers [20] connect to the manufacturer’s cloud via Wi-Fi, Zigbee, or
LoRaWAN [30], using data from soil sensors, weather APIs, and past trends to automate watering
schedules. Users interact with the system through mobile apps or web interfaces, often enhanced
with voice assistant integration (e.g., Alexa, Google Assistant, Apple HomeKit).</p>
        <p>These solutions are easy to set up and provide seamless remote access. Some employ AI for smart
scheduling to reduce water waste. However, they are dependent on the provider’s cloud
infrastructure, limit user customization, and tend to be more expensive, especially with
subscriptionbased models.</p>
      </sec>
      <sec id="sec-2-7">
        <title>2.2.3. Custom IoT Cloud-Based – Proposed – Approach for Irrigation</title>
        <p>In this approach, a microcontroller (ESP8266, ESP32, or Arduino) connects to soil and temperature
sensors and controls water pumps through an IoT cloud platform like Arduino IoT Cloud, Blynk, or
Firebase. Connectivity is established via Wi-Fi or GSM, and users monitor and manage irrigation
remotely through a mobile or web dashboard. The platform handles data processing and automation
logic.</p>
        <p>This solution is cost-effective, using low-cost hardware and free or low-tier cloud services, while
offering high flexibility for configuring sensors, dashboards, and rules. It also avoids vendor lock-in
by relying on open-source tools. Minor coding is needed, but far less than in server-based setups.
Usage limits may apply to free cloud plans, but the overall approach offers an excellent trade-off
between customization, scalability, and ease of deployment.</p>
      </sec>
      <sec id="sec-2-8">
        <title>2.3. Smart Security System</title>
        <p>Smart Security Systems are IoT-enabled systems with the purpose to monitor, detect, and respond
to potential threats in both residential and commercial environments. These systems leverage
sensors, cameras, and communication technologies to provide real-time alerts and remote access.</p>
      </sec>
      <sec id="sec-2-9">
        <title>2.3.1. From Scratch – Local Server-Based – Approach for Security</title>
        <p>In a local server-based setup, security components operate entirely within the home network,
ensuring full data privacy and no reliance on third-party services. Microcontrollers (e.g., ESP32,
Raspberry Pi, or Arduino) handle sensor inputs from PIR motion detectors, door/window contacts,
and cameras. Security footage is stored locally using NAS [31, 32, 33] or SD cards. A Raspberry Pi or
PC hosts a web server (Flask, Node.js, Apache) that manages user interaction and communication
with wireless devices.</p>
        <p>The microcontroller triggers alarms upon detecting unauthorized access, while more demanding
tasks like video processing require an additional processor. Alerts are sent via SMS, email, or local
apps. Remote access is possible only through VPN or port forwarding.</p>
        <p>This setup offers full control, no recurring fees, and high customizability. However, it requires
complex server configuration, dedicated hardware, and secure network management, increasing
both cost and maintenance overhead.</p>
      </sec>
      <sec id="sec-2-10">
        <title>2.3.2. Commercial IoT Cloud-Based Solutions for Security</title>
        <p>Commercial security systems [18, 19] rely on cloud infrastructure for monitoring, video recording,
and remote access. Cameras and sensors connect via Wi-Fi or proprietary protocols to the
manufacturer’s cloud, where motion or intrusion events trigger alerts and cloud-based recording.
Users receive notifications and can view live feeds through mobile apps or web interfaces, with many
systems supporting voice assistant integration (Alexa, Google Assistant, Apple HomeKit).</p>
        <p>These solutions are easy to deploy and offer seamless remote access with advanced features like
facial recognition and cloud analytics. However, they depend entirely on the provider’s cloud, limit
user customization, and often involve subscription fees for storage and premium capabilities.</p>
      </sec>
      <sec id="sec-2-11">
        <title>2.3.3. Custom IoT Cloud-Based – Proposed – Approach for Security</title>
        <p>This solution uses open-source microcontrollers (ESP32, NodeMCU [6]) connected via Wi-Fi to IoT
cloud platforms like Arduino, Blynk, or Firebase. The microcontroller interfaces with PIR sensors,
contact sensors, and optionally IP cameras. Through a cloud-linked dashboard, users monitor status,
trigger alarms, and receive push or email alerts in real time. The cloud service automates security
responses such as activating sirens.</p>
        <p>It combines low cost with high flexibility, allowing full customization of automation rules and
notifications, without vendor lock-in. While minimal programming is needed, advanced features like
video handling may require more powerful or additional processors. Free cloud tiers may also have
limits, but overall, this approach balances affordability, control, and scalability for effective security
automation.</p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>3. Methodology</title>
      <p>Here we provide the general ideas behind each of the two non-commercial implementation
approaches without focus on any specific automation scenario (Lighting, Irrigation, and Security).
Based on these we draw our conclusion. We then apply our conclusion in a case study of a home
security automation system utilizing IoT Cloud facilitates and not a Local Server. The results of the
case study system verifies our conjecture.</p>
      <sec id="sec-3-1">
        <title>3.1. From scratch Approach: Using a Local Server</title>
        <p>A from scratch method of implementing home automation uses an Arduino microcontroller with a
local server (e.g., PC or Raspberry Pi) that hosts a PHP/JavaScript dashboard. Through Wi-Fi, users
send HTTP requests, which the Arduino processes to control devices and return sensor data.</p>
        <p>Although this setup offers full control and local data handling, it has limitations. A computer must
run continuously, increasing energy use and maintenance needs. External access requires VPN or
port forwarding, and services like No-IP [34] provide DDNS for dynamic IP resolution. However,
even with DDNS, port forwarding must be configured manually, and server upkeep—including
updates and security—is required.</p>
        <p>Communication via HTTP can be slow, adding latency. Improvements include adopting MQTT
for more efficient messaging and using a secondary microcontroller (e.g., ESP8266/ESP32) for
network communication, leaving the main controller focused on sensors. These challenges support
the adoption of IoT Cloud platforms as a simpler, more scalable alternative.</p>
      </sec>
      <sec id="sec-3-2">
        <title>3.2. IoT Cloud-Based Solution</title>
        <p>The IoT Cloud-based approach marks a major improvement over traditional server-based systems.
Instead of relying on a local server, platforms like Arduino IoT Cloud, Blynk, and Firebase allow
microcontrollers such as Arduino, ESP8266, or ESP32 to connect directly to the internet via Wi-Fi or
GSM, eliminating the need for intermediary infrastructure.</p>
        <p>This simplifies remote access—users can control devices from any location through a cloud
dashboard, without requiring VPNs, port forwarding, or firewall adjustments. Cloud-based systems
reduce hardware requirements, leading to lower power consumption and easier setup.</p>
        <p>Sensor data is processed in real time by the cloud, enabling immediate response for critical
applications like security or irrigation. Cloud scalability ensures that expanding the system doesn’t
require architectural changes.</p>
        <p>Development is accelerated using prebuilt APIs, dashboards, and mobile apps, while platform
providers handle updates and backups, reducing maintenance. Security is also improved via
encrypted protocols like HTTPS and MQTT over TLS. Centralized storage enhances data analytics,
and regular system updates keep devices secure.</p>
        <p>The cost is lower than local server setups, as free or affordable cloud tiers are often sufficient. The
flexibility of open platforms also allows full customization, unlike proprietary commercial
alternatives.</p>
        <p>However, stable internet connectivity is essential, and reliance on a specific provider could lead
to vendor lock-in or pricing issues. Cloud-based storage also raises privacy considerations, requiring
trusted providers.</p>
        <p>In summary, IoT Cloud solutions offer a scalable, low-cost, and secure foundation for remote
automation. Their simplicity and flexibility make them ideal for modern systems across a wide range
of applications.</p>
      </sec>
      <sec id="sec-3-3">
        <title>3.3. Case Study: Home Security Automation Using NodeMCU and Arduino IoT</title>
      </sec>
      <sec id="sec-3-4">
        <title>Cloud</title>
        <p>This project presents a home security automation system developed with cost-effectiveness and
scalability in mind. The implementation leverages a NodeMCU board (ESP8266-based) as the primary
microcontroller, combined with a range of hardware components and cloud services for remote
monitoring and notification. The following paragraphs detail the system’s hardware configuration,
signal conditioning and isolation, user interface, cloud integration, and alternative notification
solutions.</p>
        <p>To achieve an efficient and economical design, the system utilizes a NodeMCU microcontroller
operating at 3.3V. Given that many peripheral components—such as sensors, sirens, and batteries—
commonly require a 12V supply, a dual-voltage approach was necessary. A commercially available
12V power supply was employed to power these components. However, to ensure the NodeMCU
operates reliably, the 12V input had to be strictly reduced to the 3.2–3.3V range. This voltage
regulation was achieved using an LM317 voltage regulator [5], which provided a stable 3.3V output
for the NodeMCU.</p>
        <p>To protect the sensitive logic circuitry of the NodeMCU and ensure proper interfacing between
different voltage levels, electrical isolation was implemented. The outputs from the NodeMCU that
drive the siren and buzzer were routed through optocouplers (PC817X). These devices, through their
internal photodiode, offer galvanic isolation between the microcontroller and the high-power output
circuitry. Additionally, transistors were connected on the 12V side to drive the external components
(sensors and sirens) while providing further isolation and protection. This dual approach—using
optocouplers combined with transistors—ensured that any voltage spikes or faults in the high-power
circuitry did not affect the microcontroller.</p>
        <p>For local, manual control of the system, a 3x4 matrix keypad was integrated. Although a typical
keypad configuration would require seven digital I/O pins, this implementation leveraged a specially
designed voltage divider to encode the keypad output into a single analog input. The NodeMCU’s
analog pin, which accepts voltages in the 0–3.3V range, reads the normalized values (mapped to a
range of 0–1023) corresponding to different key presses. This configuration simplifies the hardware
interface while ensuring reliable detection of user input for system activation and deactivation.</p>
        <p>The schema in figure 1 represents the General Circuit Diagram of the designed home security
automation. It respects/implements all the above (system’s hardware configuration, power
regulation, signal isolation, output control and local user input). The physical prototype, the
implemented system, can be seen in figure 2.</p>
        <p>Remote access and control were achieved by integrating the system with the Arduino IoT Cloud.
A dedicated cloud server was chosen due to its robust IoT services and strong security features. In
the Arduino Cloud, a device object—named “JARVIS” (inspired by the artificial intelligence from Iron
Man comics)—was created. This object holds various variables representing the states of sensors and
the overall alarm system. A custom graphical dashboard was implemented in the cloud, allowing
real-time reading and updating of these variables. Users interact with the system via the Arduino IoT
Cloud Remote [12] mobile application, which provides an intuitive interface for monitoring sensor
data and controlling the security system.</p>
        <p>The notification system of the security automation operates in an autonomous, state-driven [14]
manner. Each sensor is programmed with a series of states: IDLE, SENSOR_TRIGGERED,
NOTIFY_SENT, ALARM_TRIGGERED, and ALARM_NOTIFY_SENT. These states determine the
progression of the sensor’s response to detected events. For example:
Detect Mode: Sensors in this mode can progress up to the NOTIFY_SENT state.</p>
        <p>Detect &amp; SMS Mode: These sensors can trigger both notifications and additional actions.
Armed Mode: Sensors configured in armed mode can trigger the alarm if an event occurs, even if the
siren is already active, and they follow a specific countdown mechanism that eventually returns
them to either IDLE or ALARM_TRIGGERED state.</p>
        <p>This hierarchical state management ensures that the system can differentiate between minor events
and serious security breaches, thereby optimizing the response actions such as sending notifications
and activating alarms.</p>
        <p>Although Arduino IoT Cloud supports email triggers, alternatives were explored to improve
performance. These included HTTP-based email via Mailjet's API and direct SMTP email sending
from the microcontroller. However, both methods added processing overhead to the NodeMCU,
prompting the use of a secondary microcontroller. In this dual-processor setup, a secondary module
(e.g., ESP-01) manages notifications independently, communicating with the primary NodeMCU over
serial or I2C. Offloading these tasks reduces latency and ensures that the primary microcontroller's
performance is not compromised by intensive network operations.</p>
        <p>The case study demonstrates a comprehensive approach to developing a home security
automation system that is both cost-effective and scalable. By employing a NodeMCU-based
architecture with careful voltage regulation, signal isolation, and intelligent sensor state
management, the system achieves robust local performance. Integrating with the Arduino IoT Cloud
facilitates secure remote access and user-friendly control via a mobile dashboard. Furthermore,
exploring alternative notification methods and the incorporation of a secondary microcontroller
addresses the processing limitations inherent in single-board designs, ensuring real-time
performance and reliability. This multi-layered approach not only meets the immediate requirements
for home security but also provides a flexible framework for future expansion and enhancements.</p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>4. Discussions and Conclusions</title>
      <p>The integration of IoT Cloud services into automation systems marks a significant advancement over
traditional and commercial methods. Platforms like Arduino IoT Cloud and Blynk allow
microcontrollers (e.g., ESP8266, NodeMCU, ESP32) to connect directly to cloud infrastructure,
eliminating the need for a local server. This reduces hardware costs, setup complexity, and ongoing
maintenance.</p>
      <p>IoT Cloud solutions provide secure, built-in remote access via dashboards or mobile apps,
avoiding the need for VPNs or port forwarding. This capability is essential in applications like home
security, but also beneficial in lighting, irrigation, and broader automation use cases.</p>
      <p>Their flexibility and scalability enable system expansion without reworking the architecture. The
use of affordable hardware and free or low-cost cloud tiers makes them highly accessible. Unlike
proprietary commercial solutions, which limit customization, IoT Cloud systems give developers full
control over logic, interfaces, and data handling. As shown in the case study, sensor-based states can
be tailored to different needs, while protocols like MQTT reduce latency and improve
responsiveness.</p>
      <p>By shifting processing and communication to the cloud, these systems become more
energyefficient and resilient to local server failures. Although commercial products offer simplicity, they
often require subscriptions and restrict user control.</p>
      <p>While concerns remain—such as reliance on internet connectivity or vendor-specific platforms—
the benefits clearly outweigh the drawbacks. Hybrid approaches, combining local fallbacks with
cloud services, may further improve reliability.</p>
      <p>In conclusion, IoT Cloud platforms offer a cost-effective, customizable, and scalable foundation
for smart automation, enabling the development of robust, user-centric systems that can evolve with
future needs.</p>
    </sec>
    <sec id="sec-5">
      <title>Declaration on Generative AI</title>
      <p>During the preparation of this work, the author(s) used ChatGPT, Grammarly in order to: Grammar
and spelling check, Paraphrase and reword. After using this tool/service, the author(s) reviewed and
edited the content as needed and take(s) full responsibility for the publication’s content.
[32] Wikipedia, Network-attached storage. URL:</p>
      <p>https://en.wikipedia.org/wiki/Network-attached_storage.
[33] B. Callaghan, NFS Illustrated, Boston, MA, USA: Addison-Wesley, 2000. ISBN: 0-201-32570-5.
[34] P. Vixie (ed.), S. Thomson, Y. Rekhter, and J. Bound, Dynamic Updates in the Domain Name
System (DNS UPDATE). RFC 2136, Apr. 1997. URL: https://doi.org/10.17487/RFC2136.</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          [1]
          <string-name>
            <surname>Márquez-Vera</surname>
            ,
            <given-names>M.A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Martínez-Quezada</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Calderón</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Rodríguez</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Ortega-Mendoza</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          (
          <year>2023</year>
          ).
          <article-title>Microcontrollers programming for control and automation in undergraduate biotechnology engineering education</article-title>
          .
          <source>Digital Chemical Engineering</source>
          , Volume
          <volume>9</volume>
          ,
          <year>December 2023</year>
          . doi:
          <volume>10</volume>
          .1016/j.dche.
          <year>2023</year>
          .100122
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>