MODULAR SYSTEM OF SENSORS FOR MONITORING OF MUSEUMS’ INTERNAL ENVIRONMENT J. Valach* a , K. Julis ˇ a , P. S ˇ tefcová b a Institute of Theoretical and Applied Mechanics AS CR, v.v.i., Prosecká 76, 190 00 Prague 9, Czech Republic, valach@itam.cas.cz b National Museum, Václavské nám stí 68, 115 79 Prague 1, Czech Republic, petra_stefcova@nm.cz KEY WORDS: Indoor climate, sensors, monitoring, protection of museum collections ABSTRACT: The paper outlines basic concepts of the system for indoor climate monitoring being currently developed in a four-year project. The project concentrates on building system of sensors, the related infrastructure for communication between these sensors and the server for centralized data storage and processing. The components of the planned system are highly modular for adjustment to specific requirements of given collection. The project’s aim is to provide basis for remote monitoring of indoor climate and environment of exhibitions and depositories of museums, galleries, archives, etc. situated in historical buildings like castles, chateaus, town halls, where the protection of the building limits measures for indoor climate optimization. Finally the expected outcomes envisage the development of specialized sensors mainly for pest control and development of portable version of data sensing units for supervision of environmental parameters of collection during transport. 1. INTRODUCTION The supervision and control of indoor climate in museums and other institutions keeping large collections is a key factor in long term preservation of their unique items. Preservation is even more problematic in those historical buildings where the options of applicable protection techniques are further limited by multiple factors concerning conservation issues (Camuffo 2001, Cassar 1995, Huijbregts 2012). The first important step in controlling the environment is the measurement of its parameters. Simultaneously, as a second step, understanding the relation between measured environmental variables and signs of degradation advancement in typical material classes e.g. metal, leather, paper, etc. can refine setting acceptable ranges of decisive climate variables. Both steps constitute noninvasive measures and the combined introduction and assessment of their effectiveness is a major scope of the presented project. 2. PROJECT DESCRIPTION 2.1 Project Goal and Motivation The aim of the proposed system is to assemble a comprehensive network including sensing devices placed in the monitored indoor environment, dedicated server storing acquired data and a set of software tools and applications for data processing and evaluation. This kind of sensor infrastructure is actually being developed in many institutions (e.g. Child 1993, Smoohs 2012). The major differences that distinguish the presented system from other implementations are on one hand the objective to interface existing heterogeneous systems and therefore to minimize necessary investments and on the other hand the attention paid to data processing and mining. 2.2 Main concept The goal of the project is to build modular hardware platform and a unified data exchange structure enabling central processing of remote data with simultaneous supervision of indoor climate parameters and tools for evaluation of recorded data. As mentioned in previous paragraphs, the recorded data can be used not only to control indoor environment, but also for investigation of relationships between decay rate and surrounding environment for specific categories of materials. The project has started in the year 2012 and is expected to be completed by the end of year 2015. 2.3 Reuse of an Existing Infrastructure At the present time, sensors displaying and registering actual temperature and/or humidity, storing maximum, minimum and mean values are installed in many museums. As mentioned in the introductory part, preinstalled infrastructure can be also utilized for acquisition data without interference to its original function which is to control of indoor environment. These sensors, mainly temperature and humidity ones are used for HVAC (heating ventilation and air conditioning) systems, and also other sensors were installed and operated before start of the project. Some sensors are directly connected to the climate conditioning units, while other store the measured data till operator downloads data manually into another digital medium for further processing. The inconvenience of manually inspect every sensor and transferring data either to computer or to paper records makes the task to be very tedious work. Considering the long term, this state is also economically challenging as museum workers being highly skilled professionals, could curate and help collections more if freed from the duties to record and transmit data which can be easily performed by computers and networks. However digitized data raises some issues too: in many cases stored histories of indoor climate evolution already exists, but data is recorded in incompatible proprietary format and accessible only via commercial software 39