多功能汽车防撞报警器的设计摘 要：随着电子技术和汽车技术的日益结合，各种电子智能装置已经用于汽车系统中，使汽车电子产品已经成为电子产品中的一个独立门类，它为保障汽车行驶安全、降低肇事率起到了很大的作用。汽车防撞系统是一种可向司机预先发出视听告警信号的探测装置。它安装在汽车上,能探测企图接近车身的行人、车辆或周围障碍物；能向司机与乘员提前发出即将发生撞车危险的信号,促使司机实行应急措施来应付特别险情,避开损失。系统以单片机 AT89C2051 为控制核心器件，系统的硬件电路主要由超声波测距装置，汽车测速装置，显示装置组成。一般的汽车防撞装置在精度要求上很难达到标准，设计的创新在于结合了温度传感技术，使超声波测距更精确。根据电路设计原则， 首先完成总体方案的论证制定，绘制总体框图，然后分析系统的工作原理，在此基础上设计出各部分单元电路原理图，分析其工作原理，进一步完成对系统电路的设计。在对系统工作原理充分讨论的基础上，选择合适的元件型号和参数，再用 protel 绘图软件画出电路原理图。关键词：AT89C2051；温度传感器；超声波测距；汽车测速Anticollision Alarm of The Multi-functional AutomobileAbstract: The technical of the car along with the electronics technique increasingly combinative, every kind of electronics intelligence equipments have been used in the car system, making the car electronics product have become an independent door in electronics product, it is to guarantees the car drives the safety and lower the cause rate, it rises very big function.The principle of measuring distance with ultrasonic, and the influence of environment on the measuring accuracy ate introduce the reason of measuring error is analyzed. when instrument is designed, the selection of ultrasonic sensor, the ascertainment of frequency count and the influence of blind area on measurement are expounded the approach of improving measuring accuracy is pointed out, the method of correcting error with software is expound emphatically. design aims are achieved, measuring demands...
