I. Project design background and overview
According to the 2008 World Health Organization accident survey, about 50%-60% of traffic accidents are related to drinking and driving, and drinking and driving has been listed as the main cause of death in a car accident. In China, tens of thousands of traffic accidents are caused by drunk driving every year; more than 50% of the deaths caused by drunk driving are related to drunk driving. The danger of drunk driving is shocking and has become the biggest killer of traffic accidents. ". In August 2010, the 16th meeting of the Standing Committee of the 11th National People's Congress will first review the draft amendment to the Criminal Law (8), drunk driving or being sentenced. Drunk driving is frequent in the holidays, and the accidents caused not only the physical and economic losses for the perpetrators but also the infinite grief for the family. For the above reasons, I designed a car protection system device that not only can detect the driver's drunkenness and alert the driver, but also can send this data to the driver's relatives, so that the relatives can stop the driver from driving. Since the average age of drivers in China is over 35 years old, all the interface of the system is as simple and direct as possible, which is convenient for the driver to use quickly and skillfully.
Second, the project design principle
1, an overview of the principle
The system uses a super-sensitive alcohol sensor with a side-heating type semiconductor alcohol gas sensor MQ3, an ultra-low-power I-core one-chip system, and automatically detects the alcohol concentration method to determine whether the driver is drunk driving. The host circuit includes eight modules, which are an alcohol sensing circuit module, a temperature sensing module, a GSM communication positioning module, a keyboard control module, a liquid crystal display module, an audible and visual alarm module, a voice call module, and a relay control module. The system is placed in the dashboard of the car. When the driver opens the door, the alcohol detection controller is activated. At this time, the engine is locked and the car cannot be started. After the alcohol sensor is heated, the detection controller detects the gas signal detected by the alcohol sensor. Since the alcohol content is in a specific proportional relationship with the voltage signal generated after the detection of the alcohol sensor, the alcohol content can be judged based on the voltage signal. After the signal is amplified and filtered, it is converted into a digital signal by the 8-channel high-speed 10-bit ADC built in the MCU. The MCU processes the signal and judges that the alcohol content is not exceeded. The LCD display shows the current alcohol concentration and green. The indicator light (normal) lights up, the control relay does not work, and the car starts up; otherwise the red indicator light (not normal) lights up and sound and light alarms, the control relay cuts off the power of the ignition device, and the seat belt tightens, the system starts. Call the emergency contact device, measure the current position through the GSM communication positioning module and send "Alcohol concentration is too high, please discourage the driver from driving!" The message is told to the driver's relatives, at this time the driver can not start the car, fundamentally control Drive after drunk. After the car is started, the controller enters a low-power state. Only the alcohol concentration detection circuit works all the time. Once the driver is drinking during driving, the controller immediately returns to normal operation. Figure 1 system design block diagram
figure 1
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