38406243 alcohol detection system in cars(2)

7/28/2019 38406243 Alcohol Detection System in Cars(2)

1/8

1

ALCOHOL DETECTON ALCOHOL DETECTON ALCOHOL DETECTON ALCOHOL DETECTON8Y8TEM N CAR8 8Y8TEM N CAR8 8Y8TEM N CAR8 8Y8TEM N CAR8

BY

2

ABSTRACT

At present drunken drivers have increased enormously and so is the deaths due todrunken drivers. The main reason for driving drunk is that the police are not able to checkeach and every car and even if they catch any one the police can be easily bribed. Sothere is a need for a effective system to check drunken drivers.

In our alcohol detection system the ignition of the fuel is regulatedby a sensor circuit.

The sensor circuit is used to detect whether alcohol was consumed by the driverrecently.Our design also consists of a blood pulse rate sensor which is used

to check whetheralcohol is consumed while driving.

3


2/8

INTRODUCTION

Drunken drivers have been let unchecked in the society. Though there are laws topunishdrunken drivers they cannot be fully utilized as police cannot stand on every road cornerto check each and every car driver whether he has drink or not. This leads to severeaccidents as such that happened in Delhi in which a car ran over four road dwellerskilling them on the spot. So there is a necessity to develop a efficient alcohol detectionsystem.

WORKING PRINCIPLE OF ALCOHOL DETECTION SYSTEM.

CHECK FOR ALCOHOL CONSUMPTION AT STARTING

In our alcohol detection system the ignition circuit is controlled byinterfacing a set ofsensors, logic circuit and a micro processor. We know that the ignition key of a vehiclehas to be turned in two steps, one for switching on the electrical circuit and

second stepfor cranking the engine. As per our design when ever the driver turns the firststep a gasmask is dropped down from the ceiling of the car. The driver has toexhale deeply

through the mask. The exhaled air reaches the sensor unit where its checked forco2 andalcohol. The alcohol and co2 sensor unit gives output as per the condition of the airthrough the logic circuit which is sent to the micro processor. Depending upon the outputthe microprocessor controls the ignition process.

4CHECK FOR ALCOHOL CONSUMPTION DURING DRIVING

There is always a chance that the driver may not be drunk at the time of starting the carbut may drink during driving. So therefore for checking drinking during driving blood

pulse rate sensors are installed at calculated portions of the steering wheel where there ishigh probability that the hand will rest. The pulse sensor checks the pulse rateat the timeof starting and constantly checks the pulse rate at periodic intervals. If there is anysignificant reduction in pulse rate the car stops and again on trying to crank the engine themask drops down.


3/8

DESIGN OF ALCOHOL SENSOR

The basic principle of alcohol sensor is that potassium dichromate salt changesits colourwhen it reacts with alcohol. This is the principle of the alcohol detectors usedby police.Initially the potassium dichromate is in orange color which when reacts with alcohol itturns green. This color change is detected by a photo sensor which generates signal as perthe change of color.

5CONSTRUCTION

DESIGN OF SALT CHAMBER

The sensor equipment consist of potassium dichromate salt chamber in which potassiumdichromate salt pellets are loaded against the pressure of the spring loaded pis

ton. Thechambers exit is closed by a solenoid port such that when the key is turned thesolenoidgets energized and the port is opened. When the port is opened due to piston pressure asalt pellet is pushed into the testing chamber.

DESIGN OF SALT EXIT PORT

There is a necessity of the tested salt to be discharged efficientlyfrom the testingchamber. For this a solenoid port is present at the base of the testing chamber. Thesolenoid is connected to the battery of the car through the ignition switch. When the keyis turned the circuit closes which energizes the solenoid and pulls the soft iron coretowards it. Due to this the port gets closed. When the key is turned off the solenoid is deenergized and by spring action the port is opened.6

DESIGN OF THE TESTING CHAMBER

The testing chamber consist of the salt inlet port on the right, salt discharge port on thebottom along with the air inlet port, it consist of a LED on the right end and the photosensor along mith the air exhaust port on the top.

NEED FOR LED


4/8

A white light emitting LED is present in the testing chamber to produce the referencelight. This reference light is used for the comparison of the change of color bythe photosensor.

PHOTOSENSOR

A photo sensor is a device which can differentiate colors. Depending upon the variationin wavelength emitted by the object the photo sensor produces various electricalsignals.Depending upon the electrical signal the ignition can be controlled.

7NEED FOR CO2 SENSOR.

Initially the color of potassium di chromate is orange. When the driv

er is not drunkenthere will be no reaction taking place so there will be no change is color, if the driver isdrunken there will be change in color. There is also one more instance in whichthe driverdoes not breathe in at all so there will be no change in color. Ifsuch is a case then the

design is not fool proof. So inorder to overcome this defect,CO2 sensors are installed inthe system.

CERAMIC SENSORS

CO2 can be sensed by a ceramic sensor. The circuit consist of a testing chamber whichconsist of a ceramic sensor which detects the presence of CO2. The sensor consist of aceramic material like zirconia which compares the carbon-di-oxide levelin the testchamber with that of pre programmed value and generates votage as per the co2 contentwhich is sent to the logic circuit.

DESIGN OF LOGIC CIRCUIT

The various possibilities arising the above circuit are1. The driver is not drunken.2. The driver is drunken3. The driver does not exhale into the mask at all.

Consider the change of color of salt as logic 1 and no color changeas logic zero.

Consider the presence of co2 as logic 1 and the absence of co2 as logic 0


5/8

8TRUTH TABLE FOR THE CIRCUIT

So if CO2 is detected and alcohol is is absent then power supply from batteryreaches the spark plug. If both alcohol and CO2 is detected then the supply from the battery will notreach the spark plug.

If both are undetected then also there will be no supply to the spark plug.

CO2SENSORALCOHOLSENSOROUTPUTTORELAY

1 0 11 1 00 0 09

INTERFACING THE CONTROL CIRCUIT TO THE IGNITION CIRCUIT

The battery supplies large power to the spark plug so direct interfacing of thelogic circuit will burn the ICs. so relay switches are used. The battery circuitconsist of aNC relay switch. The NC switch is controlled by a solenoid which isenergized by thesignals from the logic circuit. The power for energizing the coils is

obtained byamplifying the IC signals using a transistor.

The microprocessor is programmed with atime program for a duration of ten secondssuch that at the end of the program themicroprocessor automatically opens theignition circuit. Now when the logic circuitgives output as logic 1 the micro processors program is brought to aend without any


6/8

result so the NC is left undisturbed. When no signal is obtained from the logic circuitthats logic zero, the processors program runs fully and at the end ofthe program thesolenoid of the NC is energized which pulls the NC switch off the circuit so thecircuit isopened. Due to this the engine will not crank.

CONTROL CIRCUIT FOR COMPRESSION IGNITION ENGINE.

In this case a solenoid actuated needle is inserted into the spring nozzle which iscontrolled by the signal from the micro processor. So when logic 0 is detected the needlewill be fully inserted and no fuel spray takes place else normal operation is carried out.

10

SEQUENCE OF OPERATION FOR ALCOHOL DETECTION SYSTEM WHILESTARTING

1. The driver puts the ignition key and gives the first step turn.This closes theelectrical circuit of the car.2. The solenoid port opens and the mask is dropped down, at the same time the saltinlet port of alcohol testing chamber is opened and exit port is closed.3. The driver exhales into the mask.4. Air reaches the testing chamber and detection process is carried out.5. Depending upon the output the engine is cranked.

DETECTION OF ALCOHOL DURING DRIVING

The fact used in this process is that on consumption of alcohol thepulse ratedecreases. But the pulse rate varies significantly for different persons. So after intialtesting the pulse rate of the person is recorded using pulse sensors.The pulse sensors

consist of very sensitive miniature piezo flim which gets deflected bythe blood pulses.

The number of pulses per minute is recorded by a counter circuit . The initial reading istaken as reference and periodic checks are made by the sensors, if there is significantreduction is pulse rate then the car stops.


7/8

11DESIGN OF PULSE SENSORS

The pulse sensors consist of the piezo electric transducers. The piezo electrictransducer can sense small mechanical vibrations produced by the bloodpulse which issent to the microprocessor. The piezo film was attached to the wristwith cloth athletictape. The sensor was placed over the pulse point as shown in Figure. The adhesive on thistape is designed to be attached to the skin, and is breathable. It

s a fairly weak adhesivewhich also allows the tape to be removed without damage to the piezoelement. We

know that when a person gets drunk his pulse rate decreases. This principle is used in thedetection process while driving. However the pulse rate may vary from person topersonso when the driver has passed the test at the time of starting the car, his pulse rate is noted

as the reference pulse rate. The pulse rate is then periodically checked and if there is adrastic decrease in the pulse rate the car stops and to start the car he has togo through theprocess again.

ADVANTAGES1. It helps in reducing road accident at a large extent.2. It eradicates the inconvenience caused when a driver is pulled down by the police

the check whether he has consumed alcohol.3. The time taken for the test is maximum ten seconds4. The cost for installation is very cheap.5. Huge alteration in design of the car is not required.12

CONCLUSION

Thus a design to efficiently check drunken driving has been developed. By implementing

this design a safe car journey is possible decreasing the accident rate due to drinking. Byimplementing this design drunken drivers can be controlled so are theaccidents due todrunken driving. Government must enforce laws to install such circuit is every car whichare already on road and must regulate all car companies to preinstallsuch mechanisms

while manufacturing the car itself. If this is achieved the deaths due to drunken drivers


8/8

can be brought to zero percent.

38406243 alcohol detection system in cars(2)

Documents