The Design Of High Accuracy Metal Film Touch Switch With The Function Of Bending And Adding

With the development of the smart system and the function of devices are becoming diverse, the normal mechanical switch cannot satisfy the requirements of the times, so the multi-function switches emerged. These control switches are gradually called smart switches. These smart switches are divided into different categories according to the functions, such as touch-sensitive switch, pressure switch, sound and light control switch, temperature and humidity switch, etc., while this thesis is focus on metal-film touch switch. Currently, the touch switch are applied in many occasions. According to different principles, it can be classified into the following common categories:the switch using the light blocking effect of the principle of transmission switch, the switch using human capacitive, and the switch using body resistivity. They all use touching action to achieve the function of opening and closing the switch even though the principles are different. These switches have two parts:switch control parts and devices starting section, this design can be more safety and effective to control the system. Most touch switches are installed on a plane, less application focuses on curved or multi-dimensional plane and the number of switches is limited. To solve these problems, this paper presents a novel touch switch that is flexible and its shape is free to design. More importantly, it is free to increase or decrease the number of switches in the system, without affecting the overall distribution circuit.Main contents of this paper are as follows:The current status of the switches is simply analysis in first chapter, the background and significance of the touch switch also introduced. According to the research status about touch switch in domestic and foreign and the future trend of development, several research methods are described and the design scheme and the implementation of this study is proposed.The touch switch category is introduced in second part, and then describes the overall design of the touch switch system. After giving a structure diagram of the touch switch system and also the diagram of each corresponding parts, system works and workflow are proposed. Simulation tool of these system also be introduced in detail in this chapter.The selection of material of touch panel in this system is analysis and chooses a suitable panel material in third chapter. Then electrical properties of the human when touching the touch panel are described in detail. This paper establishes an equivalent circuit model of human body and described the drain circuit between human body and touch panel. The safety of switch also analyzed at last.The design model of control circuit part of touch switch system is presented in fourth chapter. And then analyzes the structural characteristics and advantages of the microcomputer PSoC used in this system. Not only the function of each specific circuit in switching control part is described in detail, but also do simulate this control part. The simulation results verify the effectiveness of the control circuit in this touch switch system.The fifth chapter describes the design principle of the touch switch detection circuit, the circuit structure, and current-voltage conversion circuit, differential amplifier circuit used for detection part. Results of simulation about the detection circuit show that the detection method this system uses can recognize the touched switch under the circumstances of a plurality of switches in the system.The experimental environment of touch switch system is talked in sixth chapter. The touch switch system is based on the software PSoC Designer produced by Cypress Company to program the MCU and also composed by the Peripheral circuit.Experiments include testing different shapes and different numbers of touch switches, and then do error analysis and power analysis according to the experiment results. The results show that the touch switch in this paper can realize the function of bending and increase or decrease, the accuracy of switches is satisfy for the needs of most equipments, but the power consumption is slightly larger.Finally, a summary is given about the research process of the high accuracy touch metal film switch proposed in this paper, and proposed the research direction for further optimization in the future work.