单片机酒精电子鼻外文文献及翻译
Foreign information：Design of a Electronic Alcohol Nose Based on MSP430 Wenhua Gao
College of Electronic Information and Engineering, Taiyuan University of Science and Technology,Taiyuan, Shanxi, China.
Abstract
The paper introduced the electric alcohol nose system which consists of alcohol sensor, MSP430 MCU and peripheral units. The electric alcohol nose system can recognize and check the concentration of alcohol in the gas breathed by a drunk driver or a driver who drink alcohol. The system is described from two aspects of hardware and software. The hardware system is a typical application system consisted of MSP430 MCU, which used many inner resources of MCU and interfacing technology and with low power consumption. The system can be communicated with PC by serial communicate interface. MCU software was programmed in C language.
1. Introduction
In recent years, the people’s living standard improving a lot and the number of the vehicle on the road increasing very fast, a Traffic Accidents may happen when the driver drink alcohol. It is reported that every year the number of the people involves in Traffic Accidents in the world exceeds 600,000, and the 原文请找腾讯752018766辣,文'论~文^网http://www.751com.cn number of the people injured seriously exceeds 400,000. In order to solve the problem, by checking the concentration of the gas breathed by a driver, we can judge whether a driver drinks alcohol and know the quantity of the alcohol. Theoretically, judging whether a driver drives after drinking, the most accurate method is to check the quantity of alcohol in the blood of the driver. Taking blood on the road is inconvenient and almost impossible, so the more simply and feasible method is to check the quantity of the gas breathed by a driver. The electric alcohol nose can test the alcohol quantity of a driver expediently and save the important
data at any time.The electric alcohol nose has features as follows:
•It is small and portable.
•MSP430F449 is a kind of MCU with ultra-low-power consumption, so it can be used for a long time with just one battery[1].
•The important data is saved in the FLASH register, which makes the system more stable and safe.
•The gathered data is sent to the computer to be saved and processed.
2. Construction
The electric alcohol nose includes several parts as follows: MSP430F449, MQK2 alcohol sensor,
alarming model, display model and so on. The block diagram is shown as figure 1.
Figure 1. Diagram of the system
2.1 The electric alcohol nose use MSP430F449 MCU as the core of the system. MSP430F449 has some features as follows:
The function of MSP430F449 is very strong, because the inner part of which integrates with A/D converter and LCD display driver. Many functions of hardware can be completed by software, and then its peripheral circuits become simple, and the system becomes much stable. Exploitation of software is convenient and easy. The applied program of MSP430 can be exploited through two methods: hardware simulation and software simulation. Namely, it can use IAR Embedded Workbench to make software simulation on the computer, and make hardware simulation by downloading the program to the circuit board[2].
MSP430 MCU can work with low voltage (1.8V-3.6V) and has the virtue of ultra-low-power consumption, which makes the time span of changing battery much longer. The time span from sleep to wake is less than 6μs, which shows the good feature of real-time.
2.2 MQK2 alcohol sensor has the features as follows:
•It is very sensitive to alcohol gas.
•Better repeatability and long-time stability.
•Linear +10.0mV/℃ scale factor
•Operating voltage is from 4 to 30 voltages.
2.3 The integrated ADC12 module of MSP430F449 is used to sample and convert data. The features are as follows:
•The speed of sampling is fast.
•The inner part of ADC12 module has sampling and holding circuit.
•Several kinds of clock source can be selected.
• 8 outside channels and 4 inner channels are configured.
•The inner reference voltage is placed.
2.4 Display module
The integrated LCD is used to display information.
2.5 The bell is used to alarm.
3. Scheme
The Principle diagram of the system is shown in Figure 2. XTAL1 is an oscillator of 8M frequencies and it is used to provide the system clock. The key 0 to 9 is used to input digital. When the key of “check” is pressed, the system will sample and convert data. When the key of “send” is pressed, the system will send the data to the computer automatically and save the data in FLASH. When pressing the wrong number, we can press the key of “clear” and then input the right number. In figure 2, U2 is alcohol sensor. H-h is the heat point, which is used to make the sensors heated and its working voltage is 5V. A point is the first measure point and its working voltage is from 5V to 24V, here we use 9V. LM358 is an amplifier, and it is used to be a voltage-follower. Because the signal from the sensor is sent to MCU directly, as a load, the MCU will effects on the signals. Therefore, we add a voltage-follower between the alcohol sensor and the MCU (the resistance of the voltage-follower is very big, so the effects that the MCU has on the signal will be very small). The diode behind the LM358 will filter the signals, which we don’t need.1625