Building Automation System Using Wireless Sensor Network (WSN)

[Laura Arnold]

Contact Information

University and Department: University of Mosul, Iraq

Team Members: Qutaiba Ibrahem Ali (with help from Bashar Abdul Aziz and Nassr Meacer)

Project Information

Products Used:
LabVIEW TM

PCI-6251M TM DAQ

LabVIEW TM drivers for Crossbow Wireless nodes

The Challenge:
Designing a building automation system using wireless sensor network integrated with NI products.

The Solution:
NI products integrates successfully with wireless sensor nodes and act as the main system controller in a flexible and efficient manner.

Abstract:
Automatic control and monitoring of the building environment is an important application of Wireless Sensor Networks (WSN). We have deployed a medium scale WSN consists of 15 nodes and covers 12 rooms in an office building that in currently in-use. In the current work, WSN solutions from Crossbow Inc. were successfully integrates with the NI products. Our system consists of many wireless nodes, distributed around the building’s second floor, used to measure variouse physical quantities , such as heat, light, humidity and vibration. Based on the measurent process , a central conntrol PC supplied with LabVIEW based GUI program used to receive the data packets from the wireless sensors (via gateway node), then taking the different control reactions. The implementation of the control actions into an actuating signals were acheived via PCI-6251M DAQ card.

1. Introduction
Building Automation Systems (BAS) are used to both improve the indoor climate in buildings and to reduce the operational costs. Originally, BAS mostly consisted of heating, ventilation and air-conditioning (HVAC) systems. To further increase management and reduce costs, lighting, safety, security, and transportation supervision have been integrated into BAS. Traditionally, BAS have been used in large buildings such as schools, hospitals, and offices.

For such buildings, the construction costs constitute only one seventh of the overall operational costs. Hence, BAS provide a great savings potential by reducing the operational costs [1]. Wireless sensor networks (WSN) consist of small sensor nodes that sense the environment, perform computations, and communicate with other nodes using the onboard radio module. Typically, sensor nodes transport the measured data to a base station using multi-hop communication. The size of typical sensor nodes is close to a matchbox. Sensor nodes are typically powered by batteries. Since it is in general not possible, or too labor-intensive, to replace the node batteries, reducing power consumption is important in wireless senor networks. Since wireless communication is the major energy consumer, a particular focus has been on power efficient communication protocols for wireless sensor networks [2].

Integrating WSN and BAS has a number of advantages. The main advantage is that the installation costs of WSN are lower than that of traditional BAS, since wiring is avoided. New buildings can therefore be equipped with a BAS based on wireless sensor network technology. It is also possible to extend an existing BAS in order to increase the sensor coverage. The decreased installation costs make it possible to increase the number of sensors and hence the spatial resolution. The increased spatial resolution allows for more fine-grained measurements and control. A further advantage is that wireless technology enables temporary measurements: a network can be set up to perform measurements during a limited time in order to measure, optimize and evaluate the effect of the optimization. We call such an effort ad hoc benchmarking.

Furthermore, wireless sensors can also be installed more easily in unapproachable places such as at high heights [3]. In this paper, we show that it is possible to implement a complete system for building automation based on typical resource-constrained sensor nodes found in wireless sensor networks in addition to the flexible design environment provided by NI products.

Crossbow WSN-EDU2400CA MICAz Classroom Kit
This kit provides an easy and cost-effective solution to get a deep experience with wireless sensor networks either in the 2.4GHz (our case) or 868/916 MHz ISM bands. The kit provides all the components needed for rapidly deploying a wireless sensor network. The sensor nodes and gateway are preconfigured with Crossbow’s reliable, self-forming, self-healing mesh networking software (XMesh)[4].

The development of custom sensor applications is enabled through Crossbow’s MoteWorks™ software platform, which is available as an option with the kit. MoteWorks™ is specifically optimized for lowpower battery-operated networks and provides support for [4]:
• Sensor Devices: Network stack and operating system, standards support (802.15.4), over-the airprogramming and cross development tools. These devices are packaged, Pre-programmed Wireless Sensor Nodes for Temperature, Humidity, Barometric Pressure and Ambient Light Monitoring.
• Server Gateways: Middleware for connecting wireless sensor networks to enterprise information and management systems.
• User Interface: Client application for remote analysis and monitoring, management and configuration of the sensor network.

Description of the Current Work
The testbed is deployed in a realistic setting provided by the office building of the computer engineering department at Mosul university campus. The instrumented area covers 12 rooms of the second floor of the building, using 15 nodes.

The system consists of many wireless sensor nodes, distributed around the building’s second floor, used to measure variouse physical quantities, such as heat, light, humidity and vibration. Based on the measurent process , a central conntrol PC supplied with Labview based GUI program used to receive the data packs from the wireless sensors (via gateway node), then taking the different control reactions. The implementation of the control actions into an actuating signals were acheived via PCI-6251M DAQ card, see Figure(1).

Figure(1): Structure of the Suggested Building Automation System

We intend to use the suggested building automation system for the following purposes:
1. Performing air conditioning automation tasks using Temperature sensors distributed around the floor. Actuating signals goes from the central control PC to main air conditioning system to change its states according to previously programmed thermal values.
2. Development of a fire alarm system using the temperature sensors mentioned earlier.
3. Light control function using the measurements provided by light & motion detector sensors. When “No Motion” signal is received from a particular location in the building for a determinate amount of time, the central control PC generate an actuating signal to decrease light intensity in that area.
4. Humidity control using These quantity sensors. Actuating signals are sent to the windows automatic control system.
5. Implementing a building security system using motion detectors localized in suitable locations.

Figure (2) shows the deployment layout for the second floor of the building. All the sensor nodes are connected to the wired infrastructure (through the gateway server node) via a USB bus interface. LabVIEWTM drivers for Crossbow Wireless nodes were installed and act as the bridge between central
control PC and the sensors.

In the initial phase of the deployment, the tested only supports in-building monitoring of the mentioned physical quantities. In the future, actuators will be added and a control algorithm will be developed to achieve full building automation.

Figure (2): LabVIEWTM GUI of the Suggested Building Automation System

References
[1] W. Granzer, W. Kastner, G. Neugschwandtner, and F. Praus, “A modular architecture for building automation systems,” in Proc. 6th IEEE WFCS, 2006, pp. 99–102.
[2] A. Willig, K. Matheus, and A. Wolisz, “Wireless technology in industrial networks,” Proceedings of the IEEE, vol. 93, no. 6, pp. 1130–1151, 2005.
[3] J. Rabaey, M. Ammer, J. da Silva, J.L., D. Patel, and S. Roundy, “Picoradio supports ad hoc ultra-low power wireless networking,” Computer, vol. 33, no. 7, pp. 42–48, July 2000.
[4] Wireless Sensors networks Product Reference Guide 2007, Crossbow Inc., www.xbow.com.