毕业设计（论文）-暖水壶智能关闭实时控制器的设计.doc

学士学位论文

暖水壶智能关闭实时控制器的设计

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学科、专业: 电子信息工程
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暖水壶智能关闭实时控制器的设计
总计: 毕业论文 51 页
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插图 24 幅
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完成日期: 5月23日
摘要
在日常生活中,使用暖水壶接水时会发现:随着暖水壶中的水位不断升高,接水声的音调也在不断升高。由于暖水壶通常不是透明的,无法通过观察来判断暖水壶中的水位高低。通常情况下,会通过这种声音音调的变化来判断水是否已经接满。音调的变化是由频率变化引起的,找到水位变化与频率的关系,也就可以控制水流实现水快满时自动关闭的效果。
伴随着高性能的单片机与数字信号处理器的大量应用,使得实时的傅里叶变换成为了可能。本文通过硬件对声音信号采集并发送给计算机,使用MATLAB软件对实际的数据进行仿真,探求水位升高与频率的变化规律。结果发现这种声音音调的升高,体现在声音频谱信号高频分量能量的增加上。本文仿真得到了暖水瓶中水位升高时的声音频谱信号的特征,并根据暖壶中水位的升高而不断增大的高频分量,就可以控制水流实现水壶中水位快满时自动关闭。
本设计使用飞思卡尔公司生产的MC9S12X128芯片作为运算核心,采用8位A/,基于基-2按频率抽取的快速傅里叶变换算法(Fast Fourier Transform,FFT),对采集到的数据进行N=128个点的FFT运算并处理,实现伴随着暖壶接水状态的实时数据处理,并使得在暖水壶中的水位快到达瓶口时,水流关闭指示灯自动点亮。可以应用到寝室等大量使用接水设备的地方,达到节约用水、同时保障接水人安全的作用。
关键词: 基-2 FFT;暖水壶;频谱;自动关闭
Abstract
In daily lives, we can find the following phenomenon, when using the thermos to hold water. People can hear the tone of the water increases step by step, with the water level in the thermos grows. Since the thermos is opaque, people cannot judge the water level in the thermos by observing. Usually, the thermos holder can tell whether the thermos is full or not by listening to the increasing tone. The tone is created by the variation of the frequency. We can control the flow to shut down automatically when the thermos is nearly full, if we can find the relationship between the water level and the frequency.
It makes the real-time Fourier transform possible with the application of the high performance MCU and digital signal processor. The paper seek the relationship between water level grows and the frequency variation by sending the data sampled by the hardware to puter and using the MATLAB to simulate to the real data. At last, we find the raise of the tone reflect on the increase of the power in high frequency spectrum of the sound. The paper gets the characteristic of the sound spectrum signal by simulating the data. And then control the flow to make it an auto off design depending on the inc