Automobile Breathalyzer Ignition Interlock System - Report Example

?Automobile Breathalyzer Ignition Interlock System Introduction Automated breathalyzer device isan electronic device used to estimate the blood alcohol content from a breath sample. Automobile breathalyzer ignition interlock system links an alcohol sensor (a breathalyzer) to the ignition system of a car presenting some form of control in that it can only allow the car to start under conditions that the blood alcohol concentration of the driver is less than a defined limit. The limit varies across states and countries depending on the laws governing the states on drugs and alcohol for example in California the limit is 0.08. It takes various inputs mostly the driver’s breath; analyze it to see whether or not the driver is sober enough to drive. If the blood alcohol content (BAC) of the driver is more than the defined value, the system locks the ignition disabling he vehicle from starting. For many years the society has experienced drunk driving as a major problem which has claimed so many innocent lives apart from just the drunk drivers. The system not only prevent drunken drivers from driving while intoxicated, but also save many innocent lives who may fall victims of drunk driving. Executive summary An automated breathalyzer in most countries is fixed in convicted drunken drivers vehicles in order to control the vehicle ignition under the conditions that the driver’s blood alcohol content is from the sample breath is below a certain defined alcohol level. The automated breathalyzer engine ignition switch will act as safeguard ensuring that drunken drivers who are not fit to drive are out of the road. It is highly accurate as compared to the manual ways of preventing drunken drivers from driving in that it does not the ignite the car in case the blood alcohol content is above the defined amount. The system works using a simple theory of disabling a car’s ignition once the amount of the blood content level is confirmed by the breathalyzer to be more than the defined limit which may vary across different states. Before the vehicle’s engine started, the driver must first breathe not the device usually fitted at the dashboard of the car, after which the system analyses the breath and responds accordingly. That is, if the level of blood alcohol content is higher than the defined value, then the system automatically locks the vehicle’s ignition preventing the engine from starting. It therefore ensures that drunken drivers who are not fit to drive are eliminated from the road thus prevent accidents. Problem statement Public safety calls for the elimination of drunken drivers from the road in order to reduce accidents mostly related to alcohol. Statistics indicate that about 38% of the road accidents are alcohol related. Loopholes exists in the current system used to test drunken drivers on their ability to drive in that a driver who might be breaking the legal limit for blood alcohol still has the potential to pass the roadside sobriety tests. This is because the roadside sobriety tests such as testing if the drunken driver can walk in a straight line are manually done and their accuracy is quite questionable. Objectives A general objective of the automobile breathalyzer ignition interlock system is to prevent drunk drivers who are not fit to drive from driver by automatically locking the car’s ignition system unless the driver’s BAC value is lower than the defined limit meaning that the driver is sober enough to drive. Nearly 38% of road accidents are alcohol related while curbing the problem of drunk driving has proved difficult through the use of the other manual ways, the automobile breathalyzer ignition interlock system precludes the possibility of an accident and other incidents related to drunk driving such as revoking offenders’ licenses altogether. The system should be able to disable the car’s ignition system should it be found that the BAC value of the driver is higher than the defined limit depending on the state or country. Design Block Diagram Functionality/Block description Gas Sensor Also known as alcohol level indicator is usually made up of a breathalyzer that is used tom analyze the drivers breath for the content of alcohol. It is the centerpiece of the breathalyzer ignition interlock system. It accepts the drivers breathe as an analogue input, analyzes the input breathe to determine the amount or level of the blood alcohol content in the driver’s system while displaying the BAC. It converts the BAC into an electrical representation inform of voltage which is then fed into the microcontroller (signal processor) for further processing. For the system to appropriately function, the gas sensor should have a range of concentration reading as from 0.04 up to 10 mg/L, which should be beyond the scope needed for driver testing in order to improve its accuracy. The gas sensor uses a simple analog voltage interface which only requires one pin from the microcontroller or the signal processor. To help facilitate interconnectivity, interfacing boards can be used. The gas sensors can in two types: a semiconductor based sensor, mostly found in consumer system. This type of sensor is unreliable with possible inaccuracies in the sensing of the blood alcohol level. Higher-end breathalyzers on the other hand is more precise and reliable, mostly used by law enforcement. The higher-end breathalyzers can either use fuel cell technology or infrared spectrophotometer technology. For this system to be more reliable and in order to avoid failures, a gas sensor that uses fuel cell technology should be selected. This subsystem operates by oxidizing the ethanol contained in the driver’s breath which in turn is converted acetic acid. The electrical output of the reaction is measured then converted to digital signal for processing by the microcontroller. The converted output current is presented to the microcontroller as the input signal which is then passed under further processing. Basically the gas sensors collects the driver’s breathe determining its alcohol blood content converts the result in to a digital signal then feeds it to the microcontroller as an input signal which is then subjected to further processing. Microcontroller / Signal processor The microcontroller in this system is used to interface the gas sensor and the starter motor connected to the ignition system. It has a dedicated power supply and an amplifier which augments the output signal from the gas sensor to enable amble processing of the signal. Generally the microcontroller regulates the access to the ignition while triggering appropriate message to the driver or user depending on the outcome of the processed signal according to the manner in which it has been programmed. The microcontroller is programmed to respond appropriately in accordance with the input signal in that, after processing the amplified input signal from the gas sensor, it generates instructions which are output in form of an electric signal to the starter motor and the message console. It is programmed to convert the input signal from the gas sensor and convert it to an appropriate BAC value. Depending on outcome BAC value, the microprocessor follows specified algorithms internally designed in order to send the right signal as an output to both the message console and the starter motor. It compares the resultant BAC value with the defined value limit, which varies across states and countries, averagely 0.08 mg/L. If the BAC value is lower than the defined limit, then its sends a signal to the motor circuit which enables the car’s ignition system while at the same time sends appropriate message through the message console which can be inform of LED. The LED will indicate green for a BAC value lower than the defined limit while for a value higher than the defined limit, it will indicate red. Message console The message console is connected to the microcontroller and responds appropriately depending on the signal from the microcontroller. The microcontroller will send a positive signal to the message console under the condition that the BAC value is below the programmed blood alcohol content concentration. A negative signal will be sent by the microcontroller in the event that the BAC value is higher than the defined limit. The message console then reacts appropriately for example for a positive signal from the microcontroller, the LED lights blue, otherwise it indicates red warning the driver after logging the event and then starts up an alarm either through flashing lights or horn honking. It is through the message console that the driver knows whether or not he or she is sober enough to drive or not. Some message console are designed to indicate such conditions such as “Fail”, “Pass” and “Warning” Starter Motor / Ignition The ignition waits for a signal from the microcontroller after which it responds accordingly depending on the signal received. It does not start until it receives a signal from the microcontroller giving it the go ahead. When a positive signal is received by the ignition, it relays power to the starter motor which in turn sparks the gas inside the engine to start the combustion process within the engine. When a negative signal is received from the microcontroller, meaning that the BAC value analyzed from the driver’s breath is higher than the programmed, the ignition does not relay any power to the starter motor hindering the car from starting despite the efforts which may be attempted by the driver to turn ion the ignition key hoping to start the car. The microprocessor only sends a positive signal to the ignition when the BAC reading is satisfactory (less than 0.8). The relay does not supply enough power to start the electric motor responsible for ignition in case a negative signal is received. If the breathalyzer is not sampled by the driver, the system notifies him or her by a warning sound to sample or resample. The following diagram shows that algorithm used in the system before an ignition is either denied or initiated depending on the amount of alcohol in the driver’s system. Simple Algorithm Environmental requirements In any case the system electronics are to be designed and located in the car’s engine then there are a few requirements that need to be met for the system to correctly work. There is a strong need for a transformer given that the electronic components in addition to the cars internal circuitry may not be able to satisfactorily dependent on the 12 V. The transformer will therefore be required to step down the power supply to a usable limit. The sensitivity of the gas sensor has to be increased in order to increase its ability to sense the driver’s breathe from a long range within the car being that the system is located in the car’s engine. Within the engine, there are a number of environmental components such gasoline whose composition includes chemicals that has the ability to affect the breathalyzer component of the system. The breathalyzer has the lacks the ability to differentiate between ethyl alcohol and other compounds of simple chemicals nature. Gasoline fumes still exist after a car’s engine has been turned off; there is therefore a possibility that the breathalyzer pick up the fumes of gasoline from the engine mistaking it for the driver’s breath hence producing wrong results. For the system to properly work while fixed in the car engine area, a device that would absorb the gasoline fumes after the engine is turned off would be required in order to clear the engine area especially around the breathalyzer of any fumes which might bring confusion when the drivers sample breath is taken for analysis before the ignition is enabled. Without the device, the system would always disable the ignition not because the driver’s breath has an unacceptable BAC value but due to the wrong reading brought about by the presence of the gasoline fumes within the engine. The need for a temperature controlling device to maintain the ambient operating temperature of the system regardless of the environmental temperature is highly necessary. The car engine is usually at a higher temperature as compared to the other parts of the car. With the systems electronics fixed within the engine areas, an device that would control and maintain the devices temperature would be necessary being that the breathalyzer is calibrated for a particular ambient operating temperature. The system would otherwise need a heating device in order to maintain its ambient operating temperature to avoid erroneous results in cold areas since the car engine in cold areas seem to at a much lower temperature than the car. The breathalyzer component of the system seems to provide erroneous results mostly in cold areas given the fact that it is designed to work within normal temperature whereas during the cold seasons like the winter the engine seem to be at a much lower temperature at which the breathalyzer will generate artificially high readings. This comes as a problem when the engine is not fixed with a temperature controlling device to monitor the system electronics maintaining their temperature at a constant operating temperature for normal working. Without the device, drivers in cold areas or even those in normal areas but during the cold seasons they won’t be able to drive even if they are sober enough to since the system is prone to give a higher reading disabling the car’s ignition. Benefits The system has the ability to determine whether or not a driver is legally in a state to drive. After which is responds accordingly depending on the analysis result of the sampled breath. For BAC values less than the programmed limit, it will allow the driver to start the car by relaying power to the ignition system. Otherwise it renders the ignition system inactive thereby preventing the car from starting hence eliminating a drunk driver from the road. Through the regulation of the driver based on his or her BAC value from driving, the system protects the driver, the general innocent public and property form injury and damage due to drunken driving thereby saving a lot of lives and money. Unlike the manual ways of determining a drunk driver’s ability to drive, the system presents a more accurate and reliable preventive measure in dealing with alcohol related accidents which claim a lot of lives every day. The automobile breathalyzer ignition interlock system aids lowering user’s insurance given the fact that it minimizes the chances of an accident occurrence due to drunken driving. And therefore increasing the safety of not only the user, but also pedestrians, other drivers and property which otherwise could have been damaged or injured thus the increased insurance or even worse legal implications. Features The system indicates “Pass,” “Fail,” and “Warning” states of intoxication through the console message after which it can either start up an alarm in case the user it highly intoxicated to driver either by flashing lights or through a sound. The system disables the ignition if a user exceeds 0.08% BAC or the defined limit depending on the state laws governing drunk driving. The system is not permanently fixed on the car and its implementation either be added on or removed from any vehicle without interfering with the function of the vehicle. Bibliography Compton, Richard P., and James H. Hedlund. Reducing impaired-driving recidivism using advanced vehicle-based alcohol detection systems a report to Congress. Washington, D.C.: National Highway Traffic Safety Administration, 2007. Top of Form Bottom of Form Read More