文档介绍：北方工业大学毕业设计(论文) 基于单片机的便携式酒精浓度测试仪设计姓名: 张长亮____ 班级: 电 09A — 1___ 学号: 09101040102__ 指导教师: 武梦龙____ 日期: 毕业设计(论文) I 基于单片机的便携式酒精浓度测试仪设计摘要本设计实现了对不同浓度酒精的检测、显示和报警,通过适当改进可安装于汽车上用于防止酒驾的智能闭锁系统。本文用 AT89 C51单片机与 MQ- 3 型气体传感器实现了对酒精浓度的测量,并对测量数据进行显示,同时利用液晶显示浓度的高低,在浓度超过设定的阀值时蜂鸣器发出报警。此次设计主要研究了( 1)硬件方面: MQ-3 气体传感器技术参数的检测和将它接入到酒精浓度检测模块中;将采集到的模拟电压信号通过 A/D 转换,得到数字电压信号;用于显示浓度的显示模块。输入模块可改变阀值, 报警模块可在超过阀值时发出报警,同时继电器模块启动,以方便改进,用于防止酒驾。( 2)软件方面:主要研究了电压到浓度的线性转换和最终浓度值的显示。( 3)对设计的传感器进行了标定。传感器对酒精气体反应灵敏, 能在有效范围内测量它的浓度值。并且在检测低浓度酒精时误差较小,当浓度较高的时候误差相对较大,但也满足设计的需求。这次设计的优点在于对不同的区间浓度和电压转换关系做线性化处理, 简化了硬件电路的设计。设计的传感器可以检测不同浓度的酒精气体,改进之后,将继电器模块与汽车电路相连,驾驶员经酒精检测后方可启动车辆, 若超标,则继电器模块切断引擎电路,无法启动车辆。从而杜绝酒后驾车。关键词: 酒精浓度检测,单片机控制, A/D 转换毕业设计(论文) II Portable A lcohol T ester IsD esigned B ased On MCU Abstract This design has realized the detection of different concentration of alcohol, display and alarm, by appropriate improvements can be mounted on the vehicle to prevent drunk driving intelligent locking system. Different concentrations of alcohol solution are detected and showed in the design by AT89C51 and MQ -3 type gas sensor, and the measured data show that using LCD display concentration at the same time, the concentration exceeds the threshold of the set alarm buzzer. This design is mainly studied: (1) hardware : MQ -3 gas sensor technology parameters detection and it access to the alcohol concentration detection module; Will gather to analog voltage signal through A/D conversion, digital voltage signal; Used to display the concentration of the module. Can change the threshold input module, alarm module can send alarm over the threshold, relay module starts at the same time, to facilitate improvements, to prevent drunk driving. (2) software: mainly studies the linear transformation and voltage to the concentration of the final density of the display. (3) on the design of the sensor calibration. Sensitive response to alcohol gas sensor, it can be measured within the effective range of density. And in detect