Indoor and outdoor atmospheric corrosion monitoring of cultural heritage assets

The conservation state of Cultural Heritage (artefacts stored in museums, historical buildings, etc.) can be severely affected by the environmental conditions which they are exposed to. For this reason, a proper monitoring system is typically required in such locations in order to detect potentially unsafe conditions and to monitor the main atmospheric parameters as temperature and relative humidity, and/or the presence of aggressive gases. In this paper a wireless sensors network, designed and developed at Politecnico di Torino, has been employed for two long-lasting monitoring campaigns in Colombia. The architecture has been deployed both inside museums and outside on historical sites proving its capabilities. The solution is composed of small sensing nodes with volume lower than 8 cm3 and dimensions of 2.5x1.5 cm, which are capable of acquiring temperature and relative humidity for a time in excess of three years. The nodes are battery operated and communicate wireless to small Arduino-based concentrators connected to the Internet and to a cloud storage. Data from all the nodes are made available on the curator’s smart phones in real time, so that the entire site can be monitored from everywhere. The nodes have the capability of locally storing all the measurements for quality assurance and if either the internet connection is not available or the power supply is missing, the proposed system has the possibility of off-line manually uploading data to the cloud after having transferred them from the nodes to a battery-operated receiver. The monitoring campaigns, still in progress, are carried out in two historical sites: the National Museum of Colombia in Bogotà and the historical site of the Puente di Boyacá in Tunja.