Home automation has gained significant popularity in recent years, as everyday life has become easier with the rapid advancement of technology. Nearly everything today is digitalized and automated. In this paper, a system is introduced for connecting sensors, actuators, and other data sources to achieve multiple home automation functions. This system, called qToggle, relies on a flexible and robust Application Programming Interface (API), which serves as the core of a simple and universal communication framework. The devices utilized by qToggle are generally sensors or actuators that have an upstream network connection supporting the qToggle API. Most of these devices are built on ESP8266/ESP8285 chips and/or Raspberry Pi boards. A mobile application has also been created, enabling users to manage various home appliances and sensors. The qToggle platform is intuitive, adaptable, and can be expanded further by integrating additional devices and modules.
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Keywords: Internet of Things, home automation, smart homes, sensors
1. Introduction
The Internet of Things (IoT) is a networked system that connects devices and allows them to be remotely managed through the Internet. In recent years, the IoT concept has evolved considerably and is now applied in diverse fields such as smart homes, telemedicine, and industrial settings [1]. Wireless sensor network technologies incorporated into IoT support global interconnectivity of intelligent devices with enhanced capabilities [2]. A wireless home automation network, consisting of sensors and actuators that share resources and are interconnected, is the essential technology for developing smart homes. A “smart home” is part of the IoT paradigm and focuses on integrating home automation. Connecting household objects and devices to the Internet allows users to remotely monitor and control them [3]. Examples include smart light switches that can be turned on or off via smartphone or voice command, thermostats that automatically regulate indoor temperature and provide energy usage reports, or irrigation systems that can operate on a daily or monthly schedule to prevent water waste. Over the past years, smart home technologies have become increasingly widespread. Figure 1 illustrates an example of a smart home equipped with various IoT-based utilities.
One of the major advantages of home automation systems is their simple operation and management through various devices such as smartphones, laptops, desktops, tablets, smartwatches, and voice assistants. These systems provide numerous benefits: they enhance safety through appliance and lighting control, improve security with automated door locks, boost awareness with surveillance cameras, increase convenience through smart temperature regulation, save valuable time, offer greater control, and reduce costs.
Over the past decade, several IoT-based home automation systems have been introduced in academic research. Wireless-based home automation makes use of different technologies, each with its own strengths and weaknesses. For instance, Bluetooth-based systems [4,5,6] are affordable, fast, and simple to install, but their range is restricted to short distances. GSM and ZigBee are also widely adopted wireless solutions. GSM allows long-distance communication, but requires a mobile plan from a local service provider. ZigBee [7–12], a wireless mesh network standard, is designed to be low-cost and energy efficient, making it suitable for battery-powered monitoring and control devices. However, ZigBee suffers from low data transfer rates, limited transmission capacity, reduced network stability, and relatively high maintenance expenses.
Wi-Fi technology has been employed in [9,11–18]. Compared with ZigBee or Z-Wave, Wi-Fi offers clear advantages in terms of cost, ease of use, and accessibility. Wi-Fi-enabled devices are typically inexpensive, and many do-it-yourself (DIY) smart devices already support Wi-Fi, making it a more economical choice. Moreover, Wi-Fi is already common in most households, so purchasing compatible devices is straightforward. Another strength of Wi-Fi is its simplicity—only a minimal number of devices need to be connected to create a home automation setup. Since Wi-Fi is already widespread, there is no need to invest in extra hardware; a basic network is sufficient. Nevertheless, Wi-Fi is not intended for mesh networking, consumes significantly more energy than ZigBee, Z-Wave, or Bluetooth, and many routers can only handle up to around thirty connected devices.
When compared to Ethernet, Wi-Fi brings multiple benefits, such as easier connectivity for multiple devices, scalability (adding devices without additional wiring), lower costs, and a single access point for the whole system. However, it also comes with limitations, such as restricted coverage (since walls and obstructions can reduce signal range), a cap on the number of devices, interference and propagation issues, slower speeds than wired connections, as well as concerns about Internet security and privacy.
In the field of home automation, low-cost, open-source hardware like Arduino and Raspberry Pi microcontroller boards, combined with sensors, are frequently used. Arduino-based solutions [3,19–23] are affordable, flexible, open source, and easy to program [19], and they benefit from a large, active community. Yet, Arduino is not well-suited for handling complex or advanced projects. For more sophisticated and real-time applications, Raspberry Pi is a more powerful choice. Raspberry Pi is an innovative device that is much cheaper than standard computers or mobile devices [24]. Most of its software and projects are open source, maintained by enthusiastic online communities. Python is the preferred programming language for Raspberry Pi development, as it is simpler and less complex compared to other languages. Along with being cost-effective, Raspberry Pi is energy-efficient and does not require cooling systems. Raspberry Pi-based smart home projects are presented in [9,12,15,25,26].
Similarly, ESP8266 chips are low-cost Wi-Fi modules well-suited for IoT projects. These chips, featuring a single-core processor running at 80 MHz, have been used in various home automation applications [9,21,27–30]. A comparative overview of features from home automation systems described in scientific studies over the last decade is provided in Table 1.
Another type of home automation systems is represented by commercial platforms such as Qivicon, Domintell, Loxone, and HomeSeer. These platforms support a wide range of smart home devices from multiple manufacturers, using different communication protocols for wired setups (Domintell), wireless connections (Qivicon), or hybrid approaches (HomeSeer and Loxone). They provide various automation options, including smart locking, temperature control, lighting, environmental monitoring, video surveillance (offered only by Qivicon and HomeSeer), and intrusion prevention. All solutions also include mobile applications for system management. In terms of cost, it depends on factors such as the house size, the number of devices to be deployed, and user requirements. According to [9], the minimum price typically ranges between 1,800 and 2,600 euros.
At present, a large number of open-source home automation platforms are also available [37–42]. Among the most prominent are OpenHAB [37] and Home Assistant [38], both of which share a common vision and integrate a wide variety of devices. However, OpenHAB requires technical knowledge for device integration, making it relatively complex and time consuming, whereas Home Assistant is more user-friendly but still demands significant configuration work. Their mobile apps are often less intuitive and somewhat complicated, especially for newcomers. Domoticz [39] offers a decent set of features, with most configuration performed through a web interface and plugin support for extended functionality. Yet, its interface is not particularly intuitive, and the system is limited in terms of supported devices and configurations. Calaos [40] and Jeedom [41] are two notable French open-source solutions; however, their user communities and support forums are primarily French-speaking, which restricts global adoption. A comparative analysis of the most relevant open-source platforms is provided in Table 2, where they are differentiated based on aspects such as development language, APIs, supported protocols and plugins, and the quantity and quality of documentation. Of course, these are not the only available options—[19] presents a detailed comparison of fifteen open-source solutions.
The purpose of this paper is to present qToggle, a system designed for managing multiple home and building automation tasks, including access and security control, appliance management (lighting, thermostats, air conditioning, and other devices), irrigation, and energy/power management. This work extends [43], where we introduced a building automation solution aimed at reducing COVID-19 transmission in workplaces by minimizing contact with shared surfaces and improving building management during emergencies. Unlike that earlier work, this paper focuses on general smart home applications outside of pandemic contexts.
What makes our system distinct from other solutions is summarized in Table 1, which shows differences in terms of technologies used, controllers, communication methods, user interfaces, and—most importantly—the types of applications supported. Communication technology plays a vital role in ensuring reliable operation in home automation systems. Many studies in the literature propose hybrid solutions, where wired or wireless connections are used to link sensors with nodes, and wireless methods are used for transmitting data to storage centers. For qToggle, Ethernet and/or Wi-Fi are usually sufficient. Most affordable IoT devices already support Wi-Fi, and most households can provide adequate coverage using several low-cost devices.
The choice of node and processor (controller) in an IoT-based home automation system depends on user requirements and system characteristics. While Arduino boards are common in many existing solutions, Raspberry Pi devices are frequently adopted as well, thanks to their higher processing power and ability to run more complex software and algorithms. For this reason, we selected the Raspberry Pi board for our proposed system. Our system is not intended solely for research purposes but also for real-world deployment and potential commercialization. The ESP8266 chip serves as the microcontroller for our solution, chosen for its compact size, ultra-low power usage, robust onboard processing, and storage capacity.
In many cases, home automation systems do not have continuous access to the power grid or may only receive electricity intermittently. The integration of solar power helps lower energy costs, providing a clear advantage. Beginning this year, the qToggle system presented in this work will run on solar energy, using installed photovoltaic panels, ensuring that energy consumption will no longer be a limiting factor.