Research on light pollution of the night sky has been carried out in Toruń, Poland since 2017. Initially, the measurements were conducted within a network of 24 points using a handheld sky quality meter with lens (SQM-L) photometer (Unihedron, Canada). Based on these measurements, the first accurate maps of night sky pollution by artificial light in Toruń have been developed, both in seasonal and annual terms. Using the experience gained and elements of modern technology, a decision was made to construct an automatic network of mobile devices measuring light intensity at night, covering the entire city of Toruń. This paper presents the technical characteristics of the constructed automatic measurement devices that make up the distributed monitoring network and the process of testing and using the devices. The implementation of this project has started in 2020. To accommodate the evolving expectations of different user groups and the observed trends in the concept of Smart Cities, especially those related to the communication between devices of the Internet of Things, LoRaWAN was selected for data transmission. The first stage involved the construction of a prototype of an automatic, portable and cost-effective device, which was subjected to months of field testing under operational conditions. The device was built using off-the-shelf electronic components and a housing that met the requirements for outdoor use. The next stage was to calibrate the device by simultaneously comparing the obtained results with measurements taken using professional SQM devices. This was followed by the preparation of 35 identical devices, which are already operating in the measurement network in the city of Toruń. Elements of the network are prepared in a way that allows for further expansion and makes data available in the form of an application for many recipients.

Excessive amounts of artificial light emitted into the lower atmosphere at night have already become an everyday feature of modern urban landscapes, and gradually also a phenomenon associated with areas located out- side large human settlements. Urban islands of light have been the subject of targeted research conducted for several decades by scientists representing miscellaneous fields of science. In Toruń, regular research on the phenomenon of light smog has been carried out for several years at a number of sites located throughout the city. Recently, research has been started on the variability of the night sky brightness in a vertical gradient. To this end, repeatable measurements were made at specific altitudes at two locations in the city using a drone with an automatic light metre on board. The values of the night sky brightness thus obtained allowed us to determine its variability in the vertical gradient up to an altitude of 120 m, as well as to test the possibility of using drones in targeted studies of the light pollution phenomenon.

In order to assess or determine the overall quality of the surrounding geographical environment, it is necessary to measure selected factors that directly or indirectly affect its condition. The aspects to be monitored include i.a. air pollution levels, surface water purity, soil erosion rates, as well as night sky light pollution, a phenomenon increasingly often observed with the unaided eye. To collect data on the night sky brightness on a regular basis, a remote measuring device was designed and constructed using specialised electronic components, wireless communication, programming code, a high-sensitivity digital light data logger and custom-made programme code. LPWAN networks, including LoRa technology, were developed to support a number of mobile devices where long wireless operation is a priority. To determine the potential use of LoRa technology, as well as to plan the target locations of network access gates (gateways) and the deployment of measuring devices for the collection of environmental data, tests of signal coverage and signal visibility, including measurements of its strength, were carried out in a selected, compact part of the city of Toruń. The paper presents the results of research on the visibility of the LoRa network in a built-up area, such as a university campus, using antennas of two different lengths. The obtained results can be used to design distributed measurement networks in areas with varying density of buildings.

Light pollution is an ongoing problem for city populations. Large numbers of light sources at night negatively affect humans’ day–night cycle. It is important to measure the amount of light pollution in order to effectively ascertain the amount of light pollution in the city area and effectively reduce it where possible and necessary. In order to perform this task, a prototype wireless sensor network for automated, long-term measurement of light pollution was developed for the Torun (Poland) city area. The sensors use LoRa wireless technology to collect sensor data from an urban area by way of networked gateways. The article investigates the sensor module architecture and design challenges as well as network architecture. Example results of light pollution measurements are presented, which were obtained from the prototype network.

This paper proposes a method for solving the path planning problem for a collaborative robot. The time-optimal, smooth, collision-free B-spline path is obtained by the application of a nature-inspired optimization algorithm. The proposed approach can be especially useful when moving items that are delicate or contain a liquid in an open container using a robotic arm. The goal of the optimization is to obtain the shortest execution time of the production cycle, taking into account the velocity, velocity and jerk limits, and the derivative continuity of the final trajectory. For this purpose, the velocity profiling algorithm for B-spline paths is proposed. The methodology has been applied to the production cycle optimization of the pick-and-place process using a collaborative robot. In comparison with point-to-point movement and the solution provided by the RRT* algorithm with the same velocity profiling to ensure the same motion limitations, the proposed path planning algorithm decreased the entire production cycle time by 11.28% and 57.5%, respectively. The obtained results have been examined in a simulation with the entire production cycle visualization. Moreover, the smoothness of the movement of the robotic arm has been validated experimentally using a robotic arm.