Design of A Wireless Sensor Network Based Automatic Light Controller in Theater Arts Chuan Feng, Lizhi Yang, Jerzy W. Rozenblit Electrical and Computer Engineering Department The University of Arizona Tucson, Arizona 85721 Email: {fengc, lyang, jr}@ece.arizona.edu Peter Beudert School of Theatre Arts The University of Arizona Tucson, Arizona 85721 Email: pbeudert@email.arizona.edu Abstract In this paper, an automatic lighting controller designed and built using a wireless sensor network indoor posi- tioning technology is described. This controller can au- tonomously track actors during a real-time theatrical per- formance. Kalman filter and 3-D trilateration technologies were used with Cricket wireless sensors to implement this system. In addition, an entertainment industry standard protocol DMX-512 and an efficient calibration method were applied to realize remote computerized fixture control. As far as we know, this controller is the first application of wireless sensor networks in the theater arts area. A success- ful public performance concert at the University of Arizona validated the performance of the system. 1 Introduction In this paper, we propose an automatic moving light controller which was built using a wireless sensor net- work (WSN for short) based indoor positioning technol- ogy. WSN is an interconnected wireless system of typically small low power electronic sensors that provide ubiquitous sensing and computing capabilities, through which the con- troller tracks the position of actors on the stage. It con- trols the light instruments to illuminate the actors as needed [2]. In contrast with traditional systems that rely on pre- programmed sequences, this system provides autonomous abilities to control the moving lights in real-time. Modern stage lighting plays an important part in a per- formance. The director can use the lights to alter the per- ception of shapes, direct audiences’ attention, set the mood of a scene, establish position in time and day, and trigger a variety of events. To achieve these various objectives, different types of lighting instruments and related control systems are imple- mented. One modern instruments which appeared in the- aters in the early 1980’s is an intelligent fixture (or moving light) . An intelligent fixture allows remote control of the movement of a light beam either by moving a mirror that re- flects the beam in front of the lens, or by moving the whole fixture itself. Traditionally, the moving light is pre-programmed by the lighting designer before a real time performance [9]. It is like an industrial manipulator that can only play-back what has been memorized during a training session. There are no automatic lighting devices that can track and follow actors during a show because they lack real time position infor- mation. We wanted to build a system which obtains the position of actors in real time and controls the beam of the intelligent fixture automatically. In the next section, we briefly review previous work. In Section 3 we describe the High Accurate Positioning sub- system including the wireless sensor network, Kalman fil- ter, and the 3-D trilateration algorithm. In Section 4, we present the automatic lighting control subsystem. Section 5 describes the whole system setup and implementation. In Section 6, the experiment and real performance results in the theater of the University of Arizona are presented. Sec- tion 7 discusses future work. 2 Related Work Theater lighting is one of the most important features in modern theater performance. In Disney’s “Beauty and the Beast”, which opened at the Dominion Theater in London 1998, there were 1240 lighting units, with different levels of intensity, changing color and focus on moving objects at different times [6]. In that performance, sixty seven au- tomated fixtures were used, which communicated with the control desk via the DMX 512 protocol, an entertainment industry standard based on RS485 to change the pan, tilt, in- tensity, color and gobo. These fixtures usually utilize com- Proceedings of the 14th Annual IEEE International Conference and Workshops on the Engineering of Computer-Based Systems (ECBS'07) 0-7695-2772-8/07 $20.00 © 2007