单声一闪灯报警音效集成电路

单声一闪灯报警音效集成电路 基于超声波检测的倒车雷达设计 倒车雷达(Car Reversing Aid Systems)的全称是“倒车防撞雷达”，也称“泊车辅助装置”，是汽车泊车安全辅助装置，能以声音或者更为直观的显示告知驾驶员周围障碍物的情况，解除了驾驶员泊车和起动车辆时前后左右探视所引起的困扰，并帮助驾驶员扫除了视野死角和视线模糊的缺陷，提高了安全性。 系统工作原理 倒车雷达只需要在汽车倒车时工作，为驾驶员提供汽车后方的信息。由于倒车时汽车的行驶速度较慢，和声速相比可以认为汽车是静止的，因此在系统中可以忽略多普勒效应的影响。在许多测距方法中，脉冲测距法只需要测量超声波在测量点与目标间的往返时间，实现简单，因此本系统采用了这种方法。 如图1所示，驾驶员将手柄转到倒车档后，系统自动启动，超声波发送模块向后发射40kHz的超声波信号，经障碍物反射，由超声波接收模块收集，进行放大和比较，单片机AT89C2051将此信号送入显示模块，同时触发语音电路，发出同步语音提示，当与障碍物距离小于1m、0.5m、0.25m时，发出不同的报警声，提醒驾驶员停车。 图1 系统工作原理框图 fast boat. "Moon Pro Power pole and offshore to quickly open bow. See trailing people around the Lake called "shake up, us a lift boat!......" Shen Yuezhen stood in the bow, holding a small pistol, briskly humming "Bella Ciao". Person she wanted to send guns to the Jiangsu Taihu anti-Japanese volunteer station, look for a long time never met comrade ... ... (13) Qian Guibao intensive care wounded soldiers during the war, Zhu Xi Yao bang Tao Yuan San Min, based in this village, where good mass base. In May 1939, Zhu Xi transfer 9 wounded guerrilla, Yao bang due to injury. Qian Guibao, consciously take on the task of caring for the wounded villagers, they are wounded daily diet, taken care of. A few days later, 3 injured from wounds, medical treatment failed, died. Qian Guibao, arranged to buy the coffin, washing the bodies, buried on the spot. After 10 days, the remaining number of wounded was ordered to transfer to other places. Qian Guibao, villagers ' enthusiasm to take care of the wounded, reflect the people's support of anti-Japanese patriotism. (14) mountain Bao Dai Xiuchang, eager to help the underground resistance movement in May 1939, the party member Zhuang Shaozhen according to instructions, came to the Tomb area car dam the resistance movement. He organized the Wujiang administrative team, run evening classes, to introduce youth to turn, the army's case against Japan, revolutionary Outlook on life education; by teaching the Feng Yang, the nation, said song, the sword marches such as songs and organize cultural tours and other activities, mobilize the masses, unite against Japan. Scope of activities in the joy Temple works, Miao and Hui 图2 超声波发送模块电路 硬件设计 1 超声波发送模块设计 超声波发送器包括超声波产生电路和超声波发射控制电路两个部分，超声波探头(又称“超声波换能器”)选用CSB40T，可采用软件发生法和硬件发生法产生超声波。前者利用软件产生40kHz的超声波信号，通过输出引脚输入至驱动器，经驱动器驱动后推动探头产生超声波。这种方法的特点是充分利用软件，灵活性好，但需要设计一个驱动电流在100mA以上的驱动电路。第二种方法是利用超声波专用发生电路或通用发生电路产生超声波信号，并直接驱动换能器产生超声波。这种方法的优点是无须驱动电路，但缺乏灵活性。 本设计采用第一种方法产生超声波，电路设计如图2所示。40kHz的超声波是利用555时基电路振荡产生的。其振荡频率计算式为f=1.43/((R 9+2?R 10)?C 5)。将R 10设计为可调电阻的目的是为 了调节信号频率，使之与换能器的40kHz固有频率一致。为保证555时基具有足够的驱动能力，宜采用+12V电源。CNT为超声波发射控制信号，由单片机进行控制。 fast boat. "Moon Pro Power pole and offshore to quickly open bow. See trailing people around the Lake called "shake up, us a lift boat!......" Shen Yuezhen stood in the bow, holding a small pistol, briskly humming "Bella Ciao". Person she wanted to send guns to the Jiangsu Taihu anti-Japanese volunteer station, look for a long time never met comrade ... ... (13) Qian Guibao intensive care wounded soldiers during the war, Zhu Xi Yao bang Tao Yuan San Min, based in this village, where good mass base. In May 1939, Zhu Xi transfer 9 wounded guerrilla, Yao bang due to injury. Qian Guibao, consciously take on the task of caring for the wounded villagers, they are wounded daily diet, taken care of. A few days later, 3 injured from wounds, medical treatment failed, died. Qian Guibao, arranged to buy the coffin, washing the bodies, buried on the spot. After 10 days, the remaining number of wounded was ordered to transfer to other places. Qian Guibao, villagers ' enthusiasm to take care of the wounded, reflect the people's support of anti-Japanese patriotism. (14) mountain Bao Dai Xiuchang, eager to help the underground resistance movement in May 1939, the party member Zhuang Shaozhen according to instructions, came to the Tomb area car dam the resistance movement. He organized the Wujiang administrative team, run evening classes, to introduce youth to turn, the army's case against Japan, revolutionary Outlook on life education; by teaching the Feng Yang, the nation, said song, the sword marches such as songs and organize cultural tours and other activities, mobilize the masses, unite against Japan. Scope of activities in the joy Temple works, Miao and Hui 图3 超声波接收模块电路 2 超声波接收模块设计 超声波接收器包括超声波接收探头、信号放大电路及波形变换电路三部分。超声波探头必须采用与发射探头对应的型号，CSB40R，否则将因无法产生共振而影响接收效果，甚至无法接收。由于经探头变换后的正弦波电信号非常弱，因此必须经放大电路放大。正弦波信号不能直接被单片机接收，必须进行波形变换。按照上面所讨论的原理，单片机需要的只是第一个回波的时刻。接收电路的设计可采用专用接收电路，也可采用通用电路来实现，如图3所示。 超声波在空气中传播时，其能量的衰减与距离成正比，即距离越近信号越强，距离越远信号越弱，通常在1mV,1V之间。当然，不同接收探头的输出信号强度存在差异。由于输入信号的范围较大，对放大电路的增益提出了两个:一是放大增益要大，以适应小信号时的需要;二是放大增益要能变化，以适应信号变化范围大的需要。另外，由于输入信号为正弦波，因此必须将放大电路设计成交流放大电路。为减少负电源的使用，放大电路采用单电源供电，信号放大和变换采用了一片LM324通用运算放大器，前三级为放大器设计，后一级为比较器设计。LM324既可以双电源工作，也可以单电源工作，因此能满足使用要求。为满足交流信号的需要，每一级的放大器均采用阻容电路进行电平偏移，即图3中的C7、C21、C22和C24，容量均为10μF，实现单电源条件下交流信号的放大。对于交流信号而言，电容为短路，因此前三级放大电路的增益均为10。距离较近时，两级放大的增益已能够输出足够强度的信号了，第三级有可能出现信号饱和，但距离较远时，必须采用三级放大。合理调节电位器R27，选择比较基准电压，可使测量更加准确和稳定。 fast boat. "Moon Pro Power pole and offshore to quickly open bow. See trailing people around the Lake called "shake up, us a lift boat!......" Shen Yuezhen stood in the bow, holding a small pistol, briskly humming "Bella Ciao". Person she wanted to send guns to the Jiangsu Taihu anti-Japanese volunteer station, look for a long time never met comrade ... ... (13) Qian Guibao intensive care wounded soldiers during the war, Zhu Xi Yao bang Tao Yuan San Min, based in this village, where good mass base. In May 1939, Zhu Xi transfer 9 wounded guerrilla, Yao bang due to injury. Qian Guibao, consciously take on the task of caring for the wounded villagers, they are wounded daily diet, taken care of. A few days later, 3 injured from wounds, medical treatment failed, died. Qian Guibao, arranged to buy the coffin, washing the bodies, buried on the spot. After 10 days, the remaining number of wounded was ordered to transfer to other places. Qian Guibao, villagers ' enthusiasm to take care of the wounded, reflect the people's support of anti-Japanese patriotism. (14) mountain Bao Dai Xiuchang, eager to help the underground resistance movement in May 1939, the party member Zhuang Shaozhen according to instructions, came to the Tomb area car dam the resistance movement. He organized the Wujiang administrative team, run evening classes, to introduce youth to turn, the army's case against Japan, revolutionary Outlook on life education; by teaching the Feng Yang, the nation, said song, the sword marches such as songs and organize cultural tours and other activities, mobilize the masses, unite against Japan. Scope of activities in the joy Temple works, Miao and Hui 图4 语音电路 3 语音电路设计 语音报警是指当倒车雷达探测到的距离小于所设定的安全值时，发出声音提醒驾驶员，语音电路设计如图4所示。M3720是单声一闪灯报警音效集成电路，芯片内存储一种报警音效，可直接驱动蜂鸣器发声或经外接功放三极管推动扬声器放音，同时还能驱动一只LED闪烁。该芯片各引脚功能为:5脚VDD;1脚VSS分别为电源输入端与负端，VDD电压3,3.5V;8脚X和1脚Y分别为芯片外接振荡电阻器;6脚TG为触发控制端，低电平触发有效;3脚BZ和2脚BB分别为报警音效输出端，可直接外接压电陶瓷蜂鸣器，如果驱动扬声器则由3脚BZ端引出;4脚L为闪灯输出端，可直接驱动LED发光。 软件设计 AT89C2051单片机及其开发应用系统具有语言简洁 、可移植性好、达能力强、可进行结构化设计、可以直接控制计算机硬件、生成代码质量高、使用方便等诸多优点。该系统的主程序处于键控循环工作方式，当手柄转入倒车档，主程序开始调用测量子程序、显示子程序和语音提示子程序，完成整个检测提示过程，如图5所示。 结束语 本文所设计的倒车雷达系统是保障汽车倒车安全的辅助系统，通过超声波探头发出超声波，使用高速单片机计算距离，并加入了温度补偿电路，提高了距离计算的精度。系统安装的液晶显示器可以直观的显示温度和距离，给驾驶员提供了方便。倒车时当汽车与障碍物的距离小于我们所设定的安全距离时，系统便通过语音集成电路发出报警，提醒驾驶员，防止汽车的碰撞或擦伤，具有很强的实用性。 fast boat. "Moon Pro Power pole and offshore to quickly open bow. See trailing people around the Lake called "shake up, us a lift boat!......" Shen Yuezhen stood in the bow, holding a small pistol, briskly humming "Bella Ciao". Person she wanted to send guns to the Jiangsu Taihu anti-Japanese volunteer station, look for a long time never met comrade ... ... (13) Qian Guibao intensive care wounded soldiers during the war, Zhu Xi Yao bang Tao Yuan San Min, based in this village, where good mass base. In May 1939, Zhu Xi transfer 9 wounded guerrilla, Yao bang due to injury. Qian Guibao, consciously take on the task of caring for the wounded villagers, they are wounded daily diet, taken care of. A few days later, 3 injured from wounds, medical treatment failed, died. Qian Guibao, arranged to buy the coffin, washing the bodies, buried on the spot. After 10 days, the remaining number of wounded was ordered to transfer to other places. Qian Guibao, villagers ' enthusiasm to take care of the wounded, reflect the people's support of anti-Japanese patriotism. (14) mountain Bao Dai Xiuchang, eager to help the underground resistance movement in May 1939, the party member Zhuang Shaozhen according to instructions, came to the Tomb area car dam the resistance movement. He organized the Wujiang administrative team, run evening classes, to introduce youth to turn, the army's case against Japan, revolutionary Outlook on life education; by teaching the Feng Yang, the nation, said song, the sword marches such as songs and organize cultural tours and other activities, mobilize the masses, unite against Japan. Scope of activities in the joy Temple works, Miao and Hui fast boat. "Moon Pro Power pole and offshore to quickly open bow. See trailing people around the Lake called "shake up, us a lift boat!......" Shen Yuezhen stood in the bow, holding a small pistol, briskly humming "Bella Ciao". Person she wanted to send guns to the Jiangsu Taihu anti-Japanese volunteer station, look for a long time never met comrade ... ... (13) Qian Guibao intensive care wounded soldiers during the war, Zhu Xi Yao bang Tao Yuan San Min, based in this village, where good mass base. In May 1939, Zhu Xi transfer 9 wounded guerrilla, Yao bang due to injury. Qian Guibao, consciously take on the task of caring for the wounded villagers, they are wounded daily diet, taken care of. A few days later, 3 injured from wounds, medical treatment failed, died. Qian Guibao, arranged to buy the coffin, washing the bodies, buried on the spot. After 10 days, the remaining number of wounded was ordered to transfer to other places. Qian Guibao, villagers ' enthusiasm to take care of the wounded, reflect the people's support of anti-Japanese patriotism. (14) mountain Bao Dai Xiuchang, eager to help the underground resistance movement in May 1939, the party member Zhuang Shaozhen according to instructions, came to the Tomb area car dam the resistance movement. He organized the Wujiang administrative team, run evening classes, to introduce youth to turn, the army's case against Japan, revolutionary Outlook on life education; by teaching the Feng Yang, the nation, said song, the sword marches such as songs and organize cultural tours and other activities, mobilize the masses, unite against Japan. Scope of activities in the joy Temple works, Miao and Hui