## 3 Results and Application  
The system error is less than 10 cm, and it could result in rather smooth effects on a 15-meters-wide stage, and it could work steadily while the battery lasts. Usually a show will last for about two hours, so an external battery box was used to provide about five hours' power supply. The cost of the whole system is about $597 which is a small cost for a show. The system can be reused in the play by constantly changing performance scenes. At the same time, it can save rehearsal time for actors to cooperate with screen effects. The system has been used in a series of traditional Chinese plays. In the performance of the Chinese traditional repertoire \"Tian Xian Pei\", the authors adopted the three-base station positioning mode and placed the base station behind the stage curtain (Figure 9), avoiding the impact of visual effects to the greatest extent. The antenna tag is hidden in the actress's hair to ensure that the signal is less interfered with (Figure 10), and it maintains good stability during the actor's movements. There are also some other programs that have been verified by us, such as tying the antenna tag to the actor's arm. The trigger switch is fixed to the actor's thumb and the fingertips of their forefinger, allowing the actor/actress to easily trigger the action (Figure 11). On the other hand, the occlusion of the costumes and the exposure frequency of the hand side can hide the module to the greatest extent.  
Figure 8: Bluetooth® triggering module.  
Figure 12 shows the particle smoke effect triggered by the system at the actress's position. The antenna tag in the actress's hair cooperates with the base station to generate real-time position information, and then the fine-tuning of the control points in the program focuses the position on the actor's hand range, accurately tracking the actors to make a step, turn and other actions after triggering the virtual special effects. When applying, the position of the base station and the antenna tag should be as far away as possible from the metal, so as not to affect the signal transmission and reception. In the actual test, it is found that the higher the installation position of the base station, the better the transmission and reception of the signal (but avoiding the height of the tag).  
Figure 11: The hidden trigger.  
Figure 9: Installation of the base station on stage.  
After the actual performance, the authors collected feedback from eight performers (from testing to acting, all performers who have direct contact with the system) and a few audience members. It is widely believed by the actress who triggered the special effects that the system was very flexible. Unlike traditional performances, in which the actress needed to adjust her performance with the fixed effects of the screen and rehearse stage animations with props again and again. In this system, she has more freedom to play, and it is easier to integrate into the plot and more conducive to the performance. As the mistakes caused by the props problem are correspondingly reduced, it is easier to show the complete stage effect with the new system. In terms of viewing experience, most viewers thought highly of the new version, and the special effects are more realistic than traditional one. Some viewers believe that the traditional operas that apply the new system retain the expressive power of traditional opera, while the addition of new technologies makes the visual perception more shocking, and has a positive significance in the spread of traditional art.