The constant advances in agricultural robotics aim to overcome the challenges imposed by population growth, accelerated urbanization, high competitiveness of high-quality products, environmental preservation and a lack of qualified labor. In this sense, this review paper surveys the main existing applications of agricultural robotic systems for the execution of land preparation before planting, sowing, planting, plant treatment, harvesting, yield estimation and phenotyping. In general, all robots were evaluated according to the following criteria: its locomotion system, what is the final application, if it has sensors, robotic arm and/or computer vision algorithm, what is its development stage and which country and continent they belong. After evaluating all similar characteristics, to expose the research trends, common pitfalls and the characteristics that hinder commercial development, and discover which countries are investing into Research and Development (R&D) in these technologies for the future, four major areas that need future research work for enhancing the state of the art in smart agriculture were highlighted: locomotion systems, sensors, computer vision algorithms and communication technologies. The results of this research suggest that the investment in agricultural robotic systems allows to achieve short—harvest monitoring—and long-term objectives—yield estimation.

From its emergence to the present day, traffic light control systems has been widely used to monitor and control the flow of vehicles. However, with the increasing number of public (bus) and private vehicles (car, motorcycle, and truck), urban centers are becoming more and more populous. Such phenomenon leads to traffic congestion and increases environmental and noise pollution. In order to stem the rise of such problems, large cities are adopting technological solutions, materializing the concept of smart cities. While observing traffic management systems themselves, several hardware and software solutions have been studied and implemented around the world. This paper aims to contribute to traffic signals improvement by developing a centralized traffic light control system, using a unique wireless communication network. In order to prove the system’s effectiveness, the most common types of urban intersections were analyzed. Direct control routines were implemented for network traffic lights, providing a complete control system for extraordinary events, such as closing roads due to accidents or public events. Finally, safety routines were formulated to report the operating status of the traffic light system lamps to a central management. With the aid of a logic analyzer connected to the outputs for each focal group, it was possible to set up an operating stages timing diagram of each traffic light. Thus, the system validation was achieved based on theoretical and practical timing diagrams similarities.

The development of robotic systems to operate in forest environments is of great relevance for the public and private sectors. In this sense, this article reviews several scientific papers, research projects and commercial products related to robotic applications for environmental preservation, monitoring, wildfire firefighting, inventory operations, planting, pruning and harvesting. After conducting critical analysis, the main characteristics observed were: (a) the locomotion system is directly affected by the type of environmental monitoring to be performed; (b) different reasons for pruning result in different locomotion and cutting systems; (c) each type of forest, in each season and each type of soil can directly interfere with the navigation technique used; and (d) the integration of the concept of swarm of robots with robots of different types of locomotion systems (land, air or sea) can compensate for the time of executing tasks in unstructured environments. Two major areas are proposed for future research works: Internet of Things (IoT)-based smart forest and navigation systems. It is expected that, with the various characteristics exposed in this paper, the current robotic forest systems will be improved, so that forest exploitation becomes more efficient and sustainable.

The constant increase in the number of vehicles, the lack of road traffic management and the technological limitations of traffic light control devices, contribute to increasing congestion, environmental and noise pollution. The applications involving the Internet of Things (IoT) concept have been growing around the world. Concerning the problems found in cities with large populations, the IoT applications aim technological solutions that improve the population living conditions. Most traffic light controller systems are locally programmed. In this case, to control all traffic lights in a city, besides to be a slow task, it is not possible to determine the traffic light’s operating state. In some cases a centralized control is used, allowing information exchange with all traffic lights on the network. This paper seeks to study and develop a traffic light controller electronic circuit, with centralized control topology, able to communicate with other wireless network traffic lights. All characteristics of the designed circuit were evaluated by practical system control and monitoring tests. Finally, the electronic circuit proved to be viable in terms of smart cities applications.