The bus stops system automatically
1、The bus is automatically stops the background and significance
The people of car out for provides convenient service, while the bus stops directly affect the quality of the service. Traditional stops by the crew artificially, and in this way because of its poor and working intensity effect is too great, in many big cities have been eliminated. In recent years, with the development of science and technology progress and microcomputer technology in many fields has been widely used. In the acoustic field, with various pronunciation chip microcomputer technology, can complete combined speech synthesis technology, makes the car stops controller is realized for citizens becomes possible, and thus provide a more personalized service. In view of the traditional bus stops system deficiency, combined with the use of public transport vehicle characteristics and practical operating environment, the design of a single-chip microcomputer control bus stops system automatically. The bus stops the design of automatic device is mainly to compensate for changing the traditional voice stops device must have driver control can work backward way, pitted, automatic station broadcasts six-foot-tall service term for the public and provide more humanized more perfect service.
2. The system design of each component
This system is designed hardware circuit design part: use AT89C51 as controller, through ISD4004 pronunciation chip establish speech, forming a variety of information and use the voice messages broadcast speech information and tips amplifier, and using speech, LED digital display for standing count. When the bus arrived at one site, use the keyboard control the system work, through the yukon voice circuits output speech information and tips, stood in several information LED digital tube display. The whole system hardware design including keyboard circuit and reset circuit, display driver circuit, display circuit, memory expansion circuit module. In order to realize the bus stops, namely in speech automatic six-foot-tall; and when voice prompt information and automatic reporting service term, while utilizing of LED dot matrix circuit Chinese displaying. This design is required to exploit the AT89C51 as the master control circuit design of chips, auxiliary circuit requirements including voice circuits, Chinese dot matrix display circuit, the power supply circuit, etc. The CPU control and control signals, pronunciation chip, output indicator light component. The bus station is automatically stops the car wheel design, to count the pulse Angle, will count value compared with preset value, can determine moments, attain the precise automatically stops the purpose. USES AT89C51 as main control chip, combining to foreign pulse count ISD4004 output voice pronunciation chip. System consists of pulse detection, pulse count, CPU control and control signals, pronunciation chip, output indicator light component.
About AT89C51 chip: AT89C51 it mainly consists of for the following parts: 1 eight central processing unit (CPU), piece you in memory, the pieces (Flash RAM, 4 of 8 bits two-way addressable I/O port, 1 full-duplex UART (general asynchronous receiver transmitter) serial interface, 2 16 timer/counters, multiple priority nested interrupt structure, and a piece inside oscillator and clock circuit. In AT89C51 structure, the most striking characteristics of internal contains Flash memory is, while in other aspects of the structure of the Intel corporation, the and the structure of the 8051 no much difference.
Main performance:
1. With MCS - 51 compatible
2. 4K bytes programmable flashing memory Life expectancy: 1000 times to write/wipe cycle Data retention time: 10 years
3. All the static job: 0Hz - 24Hz
4. Tertiary program memory lock
5. 128 * 8 bits inside
6. 32 programmable I/O lines
7. Two 16 timers, counter
8. Five interrupt source
9. Programmable serial channels
10. Slice clock circuit oscillator and within
The design of pulse detection circuit:
The design of the key is that the rotor turn lap count, considering the vehicles will be running in a complex environment, and the hall componets are resistant to vibrate, afraid of dust, grease, water vapor and salt fog the advantages of the pollution or corrosion, so adopt reliable hall element DN6848 as signal acquisition device, again by photoelectric couplers 4N25 input to microcontroller. Photoelectric coupler current transmission 10% ~ 25%, than for less than 10us response time.
About speech output circuit design
This series of chip required by the microprocessor or micro controller series through serial peripheral interfaces and serial interface addressing and control. The recording data is stored method of multistage storage is through ISD patent technology implementation, with sound and audio signals directly in the natural form of solid state memory, thus providing high quality replay the fidelity of speech.
ISD4004 voice recording devices for 6.4 kHZ sampling frequency, time and recording a single chip 8 points, 10 points, 12 points, 16 points several, and its use of built-in FLASH memory cost nonvolatile CaXie memory, this fast data, and it is not lost power save data department needs power consumption. The typical stored information can save time up to 100 years, the same storage unit can be repeated be recorded 10 million times.
IAD4004 chip audio output pin can drive a five thousand uefa load, when device after power up, change the power output pins for 1.2 v. to this design of chosen amplifier is LM386 is for low voltage application design audio amplifier, the working voltage of 6V, maximum distortion degree of 0.2, power frequency response to 20 ~ 100 KHZ
About LED display output design:
This circuit USES 16 * 256 destem to display 16 16 * 16 Chinese characters, using the video memory U14 to deposit the characters bitmap information. Screen points page 32, each page 16 line 8 column LED by constitute the light emitting diode, destem with a four - 16 decoder 74LS154 decode, will address A0 - A3 decode formed by two do signal, 4-16 decoder 74LS154 form a 5-32 decoder, carries on the page decode, will address A4 - A8 decode form page, choose communication, respectively, to choose a 74LS244 general 74LS244 data through this system to a page in a line of eight leds into display information.
3. The characteristics of the system and advantage
This system greatly improve the accuracy of bus stops, and reliability. Improving the service quality of the bus system. Promote the city economic development and harmonious development of traffic changes. Made up for changing the traditional voice stops device must have driver control can work means, in the bus stops behind when the station broadcasts, automatic six-foot-tall service term for the public and provide more humanized more perfect service.
公交车自动报站系统
1.公交车自动报站器的背景及意义
共汽车为外出的人们提供了方便快捷的服务，而公共汽车的报站直接影响服务的质量。传统由乘务人员人工报站，这种方式因其效果太差和工作强度太大，在很多大城市已经被淘汰。近年来，随着科学技术的日益发展和进步，微型计算机技术已经在许多领域得到了广泛的应用。在声学领域，微机技术与各种语音芯片相结合，即可完成语音的合成技术，使得汽车报站器的实现成为可能，从而为市民提供了更加人性化的服务。鉴于传统公交车报站系统的不足之处，结合 公交车辆的使用特点及实际营运环境，设计了一种由单片机控制的公交车自动报站系统。 公交车自动报站器的设计主要是为了弥补改变传统语音报站器必须有司机操控才能工作的落后方式，进站、出站自动播报站名及服务用语，为市民提供更人性化更完善的服务。
2. 系统各组成部分的设计
本系统设计主要是硬件电路设计部分：利用AT89C51 作为控制器，通过 ISD4004 语音芯片建立语音信息库，形成变化多样的语音信息，利用其功放播放语音信息以及提示语音，，同时运用LED 数码进行站数显示。当公交车到达某站点，用键盘控制本系统工作，通过育语音电路输出语音信息和提示，同时站数信息在LED 数码管上显示。整个系统硬件设计包括键盘电路、复位电路、显示驱动电路、显示电路、内存扩展电路模块。
为了 实现公交车的语音自动报站，即在进站、出站时候自动播报语音提示信息及服务用语，同时利用LED 点阵电路进行汉字显示。本设计要求利用AT89C51 作为主控芯片完成主控电路的设计，辅助电路要求包括语音电路、汉字点阵显示电路、电源电路等。CPU 控制、控制信号、语音芯片、输出显示灯组成。公交车 站自动报站器的设计，对车轮轴的转角的脉冲进行计数，将计数值与预置值对比，即可确定报站时刻，达到准确自动的目的。以AT89C51 为主控芯片，对外来脉冲计数，结合语音芯片ISD4004 输出语音。系统由脉冲检测、脉冲计数、CPU 控制、控制信号、语音芯片、输出显示灯组成。
关于AT89C51 芯片： AT89C51 单片机它主要由下面几个部分组成：1个8 位中央处理单元你（CPU）、片内Flash 存储器，片内RAM、4 个8 位的双向可寻址I/O 口、1 个全双工UART （通用异步接收发送器）的串行接口、2 个16 位的定时器/计数器、多个优先级的嵌套中断结构，以及一个片内振荡器和时钟电路。在AT89C51 单片机结构中，最显著的特点是内部含有Flash 存储器，而在其他方面的结构，则和Intel 公司的8051 的结构没有太大的区别。
主要性能：
1. 与MCS-51 兼容
2. 4K 字节可编程闪烁存储器 寿命：1000 次写/擦循环 数据保留时间：10 年
3. 全静态工作：0Hz-24Hz
4. 三级程序存储器锁定
5. 128*8 位内部
6. 32 可编程I/O 线
7. 两个16 位定时器、计数器
8. 5 个中断源
9. 可编程串行通道
10. 片内振荡器和时钟电路
关于脉冲检测电路的设计：
本设计的关键是对转轴所转过的圈数进行计数，考虑到车辆将在复杂的环境中运行，而霍尔元件具有耐震动，不怕灰尘、油污、水汽及盐雾等的污染或腐蚀语音芯片 放音电路 CP U 控制 输出显示 脉冲计数 脉冲检测 控制信号 的优点，故采用可靠的霍尔元件DN6848 作为信号采集装置，再经过光电耦合器 4N25 输入给单片机。光电耦合器的电流传输比为10%~25%，响应时间小于10us。
关于语音输出电路设计
这个系列的芯片要求由于微处理器或微控制器系列通过串行外围接口和串行接口进行寻址和控制。录音数据被存放方法是通过ISD 的多级存储专利技术实现的，用声音和声频信号的自然形式直接存放在固态存储器中，从而提供高质量回放语音的保真度。
ISD4004 声音录放器件的采样频率为6.4kHZ,它单片录放时间又8 分、10 分、 12 分、16 分几种，其采用内置费易失性FLASH 存储器，这种快擦写存储器断电不会丢失数据，所以保存数据部需要耗电。典型的被存储信息可以保存时间高达 100 年，同一个存储单元可以反复被录音10 万次。
IAD4004 芯片的音频输出引脚可以驱动一个5 千欧的负载，当器件上电后，改引脚输出的电源为1.2v.本设计中选用的放大器是LM386 是为低电压应用设计的 音频功率放大器，其工作电压为6V，最大失真度为0.2，功率频响为20~100KHZ
关于LED 显示输出设计：
本电路采用16*256 的LED 点阵显示屏来显示16 个16*16 的汉字，采用显存 U14 来存放汉字点阵信息。显示屏分32 页，每页由16 行8 列LED 发光二极管构成，在LED 点阵显示屏中，用一片4-16 译码器74LS154 进行译码，将地址A0-A3 译码形成行信号，用两片4-16 译码器74LS154 组成一个5-32 译码器，进行页译码，将地址A4-A8 译码形成页选通信号，分别用以选通一片74LS244，系统通过此74LS244 的数据线向该页的某行上的8 个发光二极管送入显示信息。
3.系统的特点和优势
本系统很大程度上提高公交车报站的准确性，可靠性。提高了公交系统的服务质量。促进城市经济发展和交通变化的和谐发展。弥补了改变传统语音报站器必须有司机操控才能工作的落后方式，在公交车进站、出站时自动播报站名及服务用语，为市民提供更人性化更完善的服务。
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