In this diploma thesis, an energy self-sufficient Bluetooth visitor counting implementa-tion for outdoor use was designed. The diploma work focuses on presenting the imple-mentation of the system in terms of the measuring device, data communication and the IoT system. Espressif ESP32 served as the microcontroller of the measuring device, which met the required functionalities for the device. The communication connection between the measuring device and the IoT system was implemented with LoRa technolo-gy, utilizing Digita's LoRaWAN service. The central part of the thesis was to examine the results produced by the developed device and evaluate the ability of the implementation to provide reliable measurement data, on the basis of which the number of visitors in dif-ferent measurement sites could be estimated. The operation of the IoT system was based on a programmed Powershell application, the main task of which was to receive process and store measurement results. In order to visualize the measurement results, a graphical reporting view was built using the Grafana Labs application, where the collected data could be viewed in real time. The function of the measurement system developed in the diploma thesis is experimentally validated in different operating environments and based on the observations made, problem situations and possible further development targets are also extensively discussed in the thesis.