Monitoring of Historical Structure by IoT Technology with Use of ESP32 Development Board

Internet of Thing technology (IoT) is currently developed and IoT commercial networks are being operated and developed in the Czech Republic, as for example LoRa or SigFox. In order to monitor structures or environments (temperature or relative air humidity etc.) with use of these technologies, very cheap hardware can be used, as is the micro controller ESP32 (or its precursor ESP8266). More substantial part of costs represents programming and adjustment for the actual measurement. This article is containing pilot verification of the measuring system based on the above technology during the monitoring of relative displacements in cracks and temperatures of environment on the building structure of cultural monument Church of St. Martin in Zlatá Olešnice. We applied the measurement with sensors of displacement across cracks of the masonry structure in combination with the measurement of the air temperature. The measurement of some cracks proved that the relative displacement is significantly independent on the temperature and, therefore, the displacement is most likely influenced by the unstable conditions in the subsoil of the structure, which is also greatly affected by a ground moisture.