ReSeMM Project – Development of a multimodal sensor network for structural and environmental monitoring. Spoke 6, Intervention site: Royal Museums of Turin
The project was carried out as part of the PNRR Spoke 6 public tender, Mission 4 “Education and Research” – component 2 “from research to business” – investment line 1.3 “Partnerships extended to universities, research centers, and companies for the financing of basic research projects” – research and innovation program “Changes – Creativity and Intangible Cultural Heritage,” funded by the European Union – NextGenerationEU.
The initiative involved, for the sites indicated in the call for proposals and in compliance with the instructions of the client and the local authorities responsible for protection, the design and supply of a multimodal sensor network and the creation of a cloud-based software platform, integrated with a geospatial database, capable of remotely managing the network, acquiring, storing, processing, and displaying the collected data in real time, and setting alarm thresholds.
The project, coordinated by the Department of Civil Engineering (DICIV) of the University of Salerno, with Prof. Luigi Petti as Scientific Director, also involved the Departments of Industrial Engineering (DIIN) and Cultural Heritage Sciences (DISPAC), together with the innovative start-up Modula S.r.l..
Objectives
Architectural and archaeological heritage is exposed to dangers and risks, not only natural and anthropogenic, but also climate change; added to this are the natural processes of degradation generated by the aging of materials and the variability of environmental conditions. With a view to the sustainable use of resources and heritage protection, the development of methodological approaches that promote minimal intervention and proactive maintenance plays a key role in the management process. The proposal aims to implement a model and an integrated multi-scale and multi-level monitoring network through the development of robust and expandable systems that guarantee constant monitoring of the state of health of assets, allowing the behavior of structures to be characterized, including through the implementation of BIM models to document the life cycle of structures and the development of predictive models.
The Royal Museums of Turin represent one of Italy’s largest and most complex cultural systems, a historic institution that brings together centuries of power, art, and architecture and now requires innovative tools to ensure its conservation and sustainable management. Their development in the heart of the city, through buildings such as the Royal Palace, the Chapel of the Holy Shroud, the Sabauda Gallery, the Royal Armory, the Royal Library, and the Royal Gardens, involves environments that are very different in terms of materials, exposure, climatic characteristics, and sensitivity to risk factors. The wealth of collections, ranging from paintings to documents, architectural structures to wooden and marble decorations, requires constant scientific monitoring to understand and control microclimatic and environmental conditions, so as to prevent progressive deterioration and plan informed restoration work. The project described in the document was created precisely for this purpose: to define an integrated system that allows for the continuous reading, understanding, and interpretation of what happens inside the historic rooms, during and after conservation work, with particular attention to two key areas—the King’s Apartment, currently undergoing restoration, and the internal courtyard with fountains and marble statues—chosen because they represent both critical points for protection and places intended for future public use.
King’s Apartment at the Royal Museums of Turin
Sensor network
The sensor network developed is based on a precise picture of the needs of individual rooms. In the King’s Apartment, also known as the “Library Room,” it is necessary to measure thermo-hygrometric parameters in great detail, distributing sensors at different heights to record any air stratification and differences between walls, windows, illuminated areas, and more shaded areas. This room contains extremely sensitive materials, such as canvases, wood paneling, wooden floors, frames, and decorative structures, on which relative humidity, temperature, light, and air quality have a direct and often invisible but significant impact on conservation. The inner courtyard, on the other hand, requires a parallel reading but adapted to the outdoors: the presence of marble, stone artefacts, fountains and surfaces exposed to atmospheric conditions requires constant monitoring of lighting, humidity and, above all, pollutants and climatic variations that can affect the degradation of materials. For this reason, the system integrates several devices, each with a specific role in data collection. A large number of LoRaWAN temperature and humidity sensors are installed to cover multiple environments and points, favoring a distribution that allows local differences and vertical gradients to be identified.
In addition, there is a light sensor dedicated to measuring light levels, which is essential for understanding the actual exposure of the works inside the restored rooms or courtyard. There is also a people counter sensor which, once the spaces are reopened to the public, will allow the impact of visitor presence to be correlated with thermo-hygrometric trends and air quality, providing a knowledge base for calibrating admissions, regulating ventilation, or planning corrective measures. An important role is also played by the indoor multigas sensor, capable of detecting a wide range of pollutants—from VOCs to corrosive gases such as NO₂, SO₂, O₃, as well as compounds such as formaldehyde, hydrogen sulfide, or ethanol—which can directly affect both the comfort of the rooms and the state of preservation of the materials. Completing the picture is an integrated environmental sensor for CO₂, TVOC, and formaldehyde, which acts as an additional tool for determining air quality and helping to build an accurate profile of indoor conditions. The selection of devices was not random: the logic is to have a widespread network that is technically sound and at the same time can be discreetly integrated into a historical context, with compact, autonomous devices equipped with wireless communication. All sensors communicate via LoRaWAN technology with two dedicated gateways, positioned to ensure complete coverage.
Table of sensors selected for monitoring the Royal Museums of Turin (TO), with indication of the data collected, the quantities required, and the device references
Technical references and number of LoRa gateways used in the monitoring system
System architecture
The system architecture is designed to combine reliability, energy autonomy, and minimal impact on the environment. Almost all of the sensors—those dedicated to temperature, humidity, light, TVOC, CO₂, formaldehyde, and people counting—are battery-powered, an essential feature in a museum setting where the installation of cables or bulky devices could be invasive or risky for decorative surfaces. The choice to favor autonomous devices also allows them to be placed in the most strategic locations, including areas that are difficult to reach or exposed to microclimatic fluctuations. The case of the indoor multigas sensor is different. Due to its advanced nature, it requires a portable power supply system and is installed on a mobile trolley: a solution that allows it to be moved between different areas of the King’s Apartment or courtyard, performing targeted measurement campaigns and comparisons between environments with different characteristics. This sensor is connected to an acquisition module with integrated LoRa via UART protocol, ensuring stable communication and smooth data transmission to LoRaWAN gateways. The two gateways, powered by the mains, collect sensor data, aggregate it, and transmit it to the external IoT platform, where it is processed, stored, and made available for long-term analysis.
The entire system is able to operate continuously, discreetly, and reliably, without altering the appearance of the rooms and ensuring continuity even in complex operating conditions. The energy autonomy of the sensors allows for prolonged operation without frequent maintenance, while the mobile trolley dedicated to the multigas sensor offers flexibility for specific studies or detection campaigns requested by restorers or museum technicians. Thanks to this distributed architecture, the Royal Museums can obtain a complete picture of environmental conditions and air quality, monitor the response of materials undergoing restoration, and prepare for the reopening of the rooms to the public.
Diagram of the monitoring system for the Royal Museums of Turin (TO) showing the devices, power supplies required, and communication protocols used