Embedding Bluetooth into green IoT for a sustainable smart living

. The development of the Internet of Things and their integration in smart cities have changed the way society work and live. Green IoT evolves around by designing, leveraging and enabling technology to support and achieve sustainable development. Hence, this study highlights on greening IoT towards a sustainable smart living. Main aim is to embed Bluetooth into Green IoT controlled device. This project in this study is named as Green IoT Bluetooth Hotmeal Container (GIoT-BHMC) which satisfies energy saving, cost effectivity, supports smart industries and smart living. The idea is reheating food using Bluetooth technology and rechargeable AA batteries installed in a food container yet rejecting the use of electricity. Reheat process is controlled by mobile application developed in an android environment. Four phases allocated for this study consisting of planning for design, development of device with Bluetooth technology, integration and testing phase and finally the implementation phase. User accept ance test was conducted too to ensure study findings meet users’ requirements. Study contributes to energy efficiency, sustainability on smart living and green metrics. To-date, GIoT plays crucial role in making a better-off citizen. In specific, efficient resource utilization, sustainability, reducing energy consumption, pollution, and e-waste are the main idea of greening the technology. This study is a practical insight towards eco-friendly and sustainable city based on emerging GIoT technologies.


Smart living and lifestyles
Sustainable development is meeting the needs of the present without give in the future generations desires.Its design technologies focus on generating energy preserving efficient systems, efficient transmission protocols and low power needs for network architectures.The idea is to collaborate with nation's worldwide towards achieving the 17 "Sustainable Development Goals (SDGs)" by 2030 shown in Figure 1.The success to attain these 17 SDG's around the world totally depends on the level of understating among nations and proactive contributions worldwide.This study aims at creating a smart lunch box using the Internet of Things (IoT).The goal is to embed Bluetooth in G-IoT technology for a sustainable smart living.The project named as Green IoT Bluetooth Hotmeal Container (GIoT-BHMC) requires hardware components of lunch box, microcontroller to serve as the brain of the GIoT-BHMC, sensors for monitoring and control, connectivity module which is using Bluetooth to establish communication between the lunch box and a smartphone and power source such as batteries or rechargeable cells to make power the IoT components.
In the development of GIoT-BHMC, features implemented are temperature monitoring to monitor the sensor inside the hot meal box as well as humidity monitoring to track the moisture levels which help to prevent food from getting too dry or too soggy.Adding to it, the monitoring features include battery management as power saving mechanism and an intuitive mobile application that connects to the hotmeal via Bluetooth.The developed application can display real-time sensor data, that allow users to set temperature preferences, and send notifications of food temperature on the developed mobile application.

Green IoT Bluetooth Hotmeal Container (GIoT-BHMC)
Current available lunch box warmer is mostly using electricity where most of them are wired, need plug-ins and non-portable.Yes, there are portable heating containers using heating pads, but of course it turns out to be dangerous to health.People often have trouble to keep up or control their food temperature in their lunch box which might cause their food does not taste good or got spoilt.This makes the method of maintaining and heating food within the lunch box are not easy especially when people are busy with office work tasks or outdoor activities.
Therefore, study aims to find solution by using G-IoT to develop a wireless and portable heating lunch box controlled and monitored by mobile application.The heating circuit is chosen to be battery powered and rechargeable to support the 7 th goal of sustainable development in SDGs.The hardware that will be used in this project is 3 layered food container, Arduino ATmega328P, Bluetooth serial port TX RX HC05, Male to Female Jumper Wire Cable and DHT11 Temperature and Humidity Sensor and 18650 Rechargeable Battery.This smart hotmeal named as GIoT-BHMC box is wirelessly control by using mobile application.GIoT-BHMC allows user to connect their lunch via Bluetooth connecting through their android devices.Through mobile application, it enables user to heat up their food based on time set up.As for the security and privacy, it requires user to enter password in order to connect and start the food reheat process.The acceptable distance for Bluetooth to receive and sent signals to GIoT-BHMC is in 5 radiuses.

Related works 2.1 Green Internet of Things (G-IoT)
The IoT has rapidly grow in recent years and is seen as key enabler in variety of applied areas such as in manufacturing, transportation, healthcare and home automation.The G-IoT focuses primarily on the energy efficiency and the reliability of the IoT concepts to eradicate the greenhouse effect [2].Previous researchers Balusamy et al., [3], Kumar et l., [4], Sodhro et al., [5], Kumar et al, [6] and Rahmani et al., [7] aimed to synergize human, data, processes, organizations, services and facilities together in exceptional ways.Thus, to attain the target of sustainable development, plans are being developed locally and internationally keeping in mind the environmental, social and economic aspects to propose for Green Internet of Things (G-IoT) [8].

Sustainable development
United Nations (UN) has addresses Goal 7 of SDGs which is "Ensure Access to Affordable, Reliable, Sustainable and Modern Energy for All".UN stated that global population with access to electricity increased from 87% (2015) to 91% (2021) [1].Adding more, UN also mentioned, 675 million people are yet to be connected to the grids and 2.3 billion are still cooking with unsafe and polluting fuels.To ensure enough access to energy by 2030, people globally hace to accelerate electrification, invest in renewable energy sources and upgrade for electricity grids.
These challenges of energy consumption, electronic waste, emission of CO2 and use of non-biodegradable IoT devices [6].This condition has formed needs for moving towards G-IoT, as upcoming technological enhancement of IoT connected with green technology and green economy.This is with the aim towards bringing promising enhancements in environmental, human wellbeing and smarter world.G-IoT has great capability to strengthen environmental and economic sustainability by using IoT technological advancements.There is an unlimited need of green technologies in sustainable development for building a smart world embed with green IoT [9].
Therefore, this research purposes on energy saving and strategies towards achieving green IoT.However, as the number of IoT devices continues to grow, concerns about their environmental impact have emerged.Many of these devices require energy to operate, and the manufacturing processes associated with them can contribute to pollution and resource depletion.Green IoT (G-IoT) solutions prioritize the development of energy-efficient devices and protocols.This includes using low-power components, optimizing communication protocols to minimize energy consumption, and incorporating sleep modes to conserve power when devices are not actively transmitting or receiving data [10].
G-IoT also encourages the use of recyclable and environmentally friendly materials in device construction, as well as proper disposal or recycling methods at the end of their useful life for a good lifecycle management.IoT for smart cities can help create more sustainable and live able urban environments by enabling better traffic management, waste collection, and energy usage optimization.By adopting these principles and integrating them into the design, deployment, and management of IoT systems, it's possible to harness the benefits of IoT technology while minimizing its negative impact on the environment.Existing studies are not broadly focusing on smart cities strategies for enabling greener smart cities.Up to date, only few addressing on IoT by relating with SDGs goals [4,7,16,17] especially on smart cities, empowering wireless ICT, reducing CO2 emissions, reducing waste management, and improving sustainability.Previous author Talari et al., [18] introduced IoT for smart cities but did not further discussed on G-IoT.
Therefore, this study fills this gap in the literature.Author Hadi et al., [19] identified IoT applications as potentially reduce energy by applying green environment.Several techniques were introduced for enabling G-IoT to facilitate energy efficiency.Other authors Balusamy et al., [3], Joshua et al., [8] and Maksimovic [9] too had discussed the concept of IoT for sustainability of smart cities and its benefits however, none addressing on development of prototype for sustainable living.A comparison of existing surveys and present work is summarized in Table 1.
Previous studies Maksimovic [9], Diraco et al., [10] Koutitas [20] on integration and communication guidelines had proposed a hierarchical architecture to cater for interoperability problem of communication networks.They aimed to support infrastructure for smart energy system and help in providing an ubiquitous communication.

Smart cities
Fabulous developments of various technologies have improved life quality in smart cities especially when applying IoT.In specific, there were studies Almalki et al., [2] and Kumar et al., [4] related to G-IoT.They focused on the efficiency of resource utilization and emerging IoT technologies.These things interacts amongst themselves and humans with efficient bandwidth frequencies utilization, energy efficiency and lesser hazardous emissions to make the city eco-friendly and sustainable.Going for G-IoT requires new resources in caring for human health and disturb the climate in order harness preservation of environment.Figure 2 shows the Green IoT Bluetooth Hotmeal Container (GIoT-BHMC) methodology which consists of four phases with three specified methods used along the experiment processes.The first phase is planning for the design of GIoT-BHMC, covering design of mobile application and heating system circuit.The design is shown in Fig 3 .The programming language used is Java while Arduino ATmega328P is used for developing the controller application.In integration and testing phase, GIoT-BHMC was tested.At this phase, every hardware and software were inspected to make sure that the whole heating system function well.The testing phase ranging from control application test, heating system circuit test and hotmeal container test.The motive was to ensure for precise elements chosen in each test.During the integrated testing implementation test, GIoT-BHMC was tested to match with its requirement before it was released for UX demonstration and user acceptance test.In implementation and deployment phase, users' requirements must be fully achieved as a proof of satisfaction.Demonstration method was arranged to fit users' needs and expectations.Through this method, it showed how GIoT-BHMC functioned.Here, UX was recorded and used to support for the succeeding of GIoT-BHMC project.Next, user acceptance test was conducted to ensure findings in demonstration and UX go align with each other.The completed integration process is illustrated as in Figure 4.The whole GIoT-BHMC system supports for sustainable smart living and energy saving.Two units of AA rechargeable batteries shown in Figure 5 is used to heat up meal in a set time of 5 minutes with the temperature of 80 Celsius.Suitable reheating types are gravy, boiled and steam food.Three layered food container, Arduino ATmega328P, Bluetooth serial port TX RX HC05, Male to Female Jumper Wire Cable and DHT11 Temperature Humidity Sensor and 18650 Rechargeable batteries were used as the hardware to complete the food heating process.This energy and cost saving approach was wirelessly control by using the mobile controlled application.Figure 7 shows the result of questionnaires that were distributed to 23 respondents randomly.More than 80 percent respondents agreed on the design and development of GIoT-BHMC.They would not mind installing control application to their android phone for easy access on portable and wireless heating system.On the other hand, chart in Figure 8 on user experience and acceptance shows clearly GIoT-BHMC is helpful for daily usage as it offers energy saving, cost effectivity, smart living communication (portable and battery powered) as well as smart sustainability cities (improve quality of life, efficiency of urban operation).Analysis has proven that GIoT-BHMC is convenient as it offers simpler method to reheat food.The monitoring system applicable in the ready mobile application makes it easy to handle and control.It is relevant, portable and self-reliant on electricity.However, Bluetooth connection is needed to utilize GIoT-BHMC.In order to connect to the Bluetooth, a user must be in the range of lesser than 5 feet or 150 cm.

Discussions
Up-to-date, Green IoT comprises of 8 smart cities application domains [2].From this study, two (2) identified domains that are closely related to GIoT-BHMC are smart industries and smart living.The details of applications, key trends and application domains is presented in Table 2.Over the use of GIoT-BHMC, energy intensity is reduced, it is eco-friendly and safe, convenient, reliable as it contributes towards home automation and most importantly, it is preferred and accepted by the society.Greening wireless technologies is a critical component of making IoT more environmentally friendly.IoT devices are becoming increasingly prevalent in various industries, especially for smart homes.This is illustrated in Fig 9 on the relationship of green technology impact to GIoT-BHMC towards acheiving sustainability.All for the purpose to improve livable, resilient, green, and sustainable living as these are directly connected with human health and well-being.

Conclusion
Urban planning has become essential in the growth of sustainable cities. Maintaining the welfare of every citizen and health are crucial as the structure of sustainable green cities are directly connected with human health and wellbeing.Energy saving and efficiency are the keys in a green sustainable city.Renewable resources, ecological footprints and reducing pollution are things to keep the city smart and green.IoT on the other hand stays vital in improving smart living towards livable, resilient, green, and sustainable.Upcoming years foresee technologies with efficient techniques that will change future ambience towards healthier, smarter, greener and high delivering quality of service (QoS).This tomorrow is what called as sustainable living.Study on GIoT-BHMC is seen as less requires on energy demand, resources substitution and minimization of IoT negative impact on humans' health.This study contributes a practical insight who wishes to venture in the field of eco-friendly and sustainable city based on emerging G-IoT technologies.For improvements, future researchers may look into areas to expand battery capacity and un-attaching batteries to the container for better method of charging.

Fig 3 .
Fig 3. Design of controller, heating system circuit and Arduino code.

Fig 5 .
Fig 5.Rechargeable AA battery used as energy and cost saving approach for a hot delicious meal.

Fig 6 .
Fig 6.Flowchart of GIoT-BHMC.The overall function of GIoT-BHMC is displayed in Fig 6.Two main systems consisting of Connection System and Heating System communicate to perform a complete food heating process empowered by rechargeable batteries.

Fig 7 .
Fig 7. Analysis results from 23 respondents on the design and development of GIoT-BHMC.

Fig 8 .
Fig 8. Analysis results from 23 respondents on GIoT-BHMC user experience and acceptance.

Table 1 .
Summary comparison of existing surveys and present work.

Table 2 .
Related trends for GIoT-BHMC in smart cities sub goals.