Modular design of a novel wireless sensor node for smart environments Massimo Grisostomi, Lucio Ciabattoni, Mariorosario Prist, Luca Romeo, Gianluca Ippoliti, Sauro Longhi Dipartimento di Ingegneria dell’Informazione, Universit` a Politecnica delle Marche Via Brecce Bianche 12, 60131 Ancona, Italy Email: {m.grisostomi, l.ciabattoni, m.prist, l.romeo, g.ippoliti, s.longhi}@univpm.it Abstract—Most of the existing commercial node architectures provide little flexibility and configurability. This limitation con- strains the usability of the same node across various applications, including the ambient intelligence issue. In this paper a novel architecture for the design of a modular wireless sensor node is proposed, dividing the connection and sensing functions in two separate boards. The division of the wireless transducer interface module (WTIM) in two independent boards allows to perform in a separate way the connection and sensor interfacing function of the WTIM always respecting IEEE 1451 standards. The versatility of the novel architecture has been tested in two different application scenarios. In the first application the modular node has been used in a factory to monitor the efficiency and reliability of the production line. The designed node has been experimentally tested and results shown. Concerning the second application, a smart home approach is proposed. Using different sensing boards, an architecture to monitor in a non-invasive way several home parameters has been presented. Index Terms—Wireless Sensors Network, Modular Wireless Node, IEEE1451 Standard, Ambient Intelligence. I. NOTES The following version of the paper has been personally revised by the authors. For further information (e.g. details on the hardware designed) do not hesitate to send an email. Sincerely Lucio Ciabattoni II. I NTRODUCTION The topic of smart environments, also called ambient intel- ligence, is nowadays one of the hottest topics in media and research centers. According to [1], smart means having the capability to autonomously collect and apply knowledge while environment is made up of our surroundings. In an engineering perspective the so called ambient intelligence can be obtained embedding sensors and actuators in an environment to auto- matically react to users, devices and machines [2]–[4]. The recent interest in this topic can be attributed to several factors. 1) The growing availability on the market of small and inexpensive sensors and devices easily embeddable. 2) The worldwide diffusion of networking technologies, such as Wi-Fi, Ethernet and Bluetooth that makes easier the communication between devices. 3) The presence of small computing devices (such as smart- phones, tablets and netbooks) in almost every dwelling. The first step to achieve the ambient intelligence is the installation in any environment of several devices to detect its state and provide information to automated control systems or human supervisors. In many cases the adoption of standard wired solutions to supply power and acquire sensors data could suffer of various problems thus making harder the realization of a sensor network (e.g. the need of expensive and often complex installation and the lack of flexibility in placing sensors). In this scenario a wireless solution adopted both for data transfer and power supply could clearly be a solution but, on the same time, still poses many challenges. Wireless Sensors Networks (WSN) technology has been widely studied in many universities and research centers in recent years [5]– [7]. WSN are composed by sensor nodes that autonomously operate gathering sensors information and combining both communication and computation capabilities in a small form factor. These nodes, establishing a wireless link, collaborate with each other to execute application tasks. The main ob- stacles to the spread diffusion of this technology are mainly represented by communication issues (in terms of reliability and latency), power supply issues (nodes battery powered need the lowest power consumption possible) and flexibility [8], [9]. While on one hand this technology offer to users the dream of a high flexibility level sensor network, in the practice there are various constraints that move the dream far away from reality. Most of the existing commercial node architectures indeed provide little flexibility, configurability and the absence of interoperability between them. Daughter boards provide sensing capabilities but the processing and communication modules are fixed and cannot be often ex- tended. These limitations constrains the cross-usability of the same node in different applications and the use of different branded nodes in the same application. Due to these problems the automation of a building can be extremely expensive through the installation of a WSN. A set of solutions for design variation and miniaturization in each of the functional circuit blocks [10]–[12] has been proposed in literature together with some initiatives to address the interoperability problem in the home automation such as UPnP (Universal Plug &Play) [13] or Jini [14]. In this paper we face the flexibility and customization problem presenting a novel architecture for the design of a modular wireless sensor node dividing the connection and sensing functions in two separate boards. The new architecture, providing a higher level of customization for the whole WSN, makes possible the implementation of different features using the same communication structure following the IEEE 1451