# A Portable Non-Motorized Smart IoT Weather Station Platform for Urban Thermal Comfort Studies
## 1 Introduction  
The rapid increase in the global urban population to 68% in 2050 [1] has led to the smart city concept as a solution for addressing urbanization challenges, such as population growth, pollution, scarcity of water, energy efficiency, etc. According to the International Institute for Management Development (IMD) Smart City Index 2024, there are 142 smart cities worldwide [2]. The main aim of smart cities is to deliver a better quality of life through better decision-making using technology, and it is categorized into Information and Communication Technology (ICT) and a people-oriented approach [3]. Holistically, smart cities can be understood as the combination of technology, government, and societyfor a smart economy, smart mobility, smart environment, smart people, smart living, and smart governance [3]. Among various smart city applications, sensors placed in plants contribute towards future food security through precision agriculture. Cloud-connected sensors present in waste bins, health trackers, homes, urban infrastructure, and vehicles help in efficient and sustainable waste collection, real-time health monitoring, efficient energy use in homes, checking the structural stability and governance of various urban infrastructures, and also address traffic problems and congestion in the city [4]. Smart cities can be understood as the use of sensors for data collection, transmission/reception of the collected data through Wireless Fidelity (Wi-Fi), Cellular, Long Range (LoRa), Zigbee, Bluetooth, Bluetooth Low Energy (BLE), and Sigfox, among other possible data communication technologies, the storage of this data in the cloud and using it for analysis [4; 5; 6]. More information and a comparison of the mentioned communication technologies can be found in [4]. However, the smart city framework has weakly considered the environmental aspects as opposed to the social and economic aspects of urban sustainability [3]. In particular, technologies measuring Urban Heat Islands (UHI) and outdoor thermal comfort are weakly studied in comparison to other urban environmental problems, such as air quality, water, and energy [7]. UHI is a phenomenon where cities are warmer compared to the surrounding rural areas [8]. The cities in the UK can get warmer by up to 8 \({}^{\circ}\)C to 10 \({}^{\circ}\)C compared to the surrounding rural areas [9]. Given the circumstances of frequent heat waves globally, UHI is an imminent threat to human life, plant and animal species, water quality, etc. Even a 1 \({}^{\circ}\)C increase in temperature demands 2 to 4% more energy for air-conditioning and refrigeration, which directly impacts the cost of living [10; 11; 12; 13]. Therefore, to integrate and increase smart cities' interest in environmental issues, especially UHI and outdoor thermal comfort, this research aims to build an Internet of Things (IoT)-based low-cost smart weather station platform with a portable weather sensor device and a centralized server to facilitate real-time data collection, monitoring, and atmospheric data storage for understanding heat stress in urban areas. The Array of Things (AoT), a fixed wireless sensor network distributed across urban areas, is one of the methods used to record and monitor real-time temperature across the city. The cities of Chicago and Seoul in South Korea used a network of 130 and 1100 fixed wireless sensors, respectively, for real-time temperature monitoring and analysis through IoT [14; 15; 16]. However, capturing the human scale UHI and thermal comfort requires fine spatial scale temperature and other atmospheric variables measurements (wind speed, wind direction, Mean Radiant Temperature, etc.). This will help architects, urban designers, and landscape architects in developing thermally comfortable and climate-responsive designs [17]. However, this is impractical and not cost-effective with fixed sensors, as it requires more sensor units in a short spatial distance.