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Road Safety Solution for Drunken Driving

Drunken driving is one of the major problems today, this causes several deaths every year across the world. Here is a simple method of sensing alcohol in the breath of the driver i.e. Breath Alcohol Concentration (BrAC) is used. This reading will help in locking the car ignition and sending an SMS text message to alert the authorities. It makes a normal car a smart car. The embedded system solution which is used here gave good results in the experiments conducted by us. It has very high sensitivity, fast response and long lifetime. If this system is implemented in the future cars, it can provide a cost-effective and power-efficient solution to the major social problem of drunken driving.


Drunken driving has been one of the main reasons behind road accidents. Driving under the influence of alcohol has affected and killed countless of people’s lives. If someone drinks and drives, not only does he possibly put himself at risk, but his passengers and pedestrians, and other people, who are on the road, are at a greater risk as well. Every thirty minutes someone’s life is cut short and families are devastated. Road accidents cause 1.2 million deaths and 50 million injuries every year around the world. Out of which 480,000 deaths and 20 million injuries are caused by drunken driving only.

Governments are taking steps to prevent drunk driving by introducing new laws like recently Supreme Court of India has ordered to close all the liquor shops near the highways. A driver having blood alcohol level of 30 mg per 100ml of blood is considered drunk according to the Indian law. The traffic police have also been provided with alcohol sensor tools to check whether the driver is drunk or not. According to the Motor Vehicle Act, 1988 a person can get an imprisonment of up to six months and penalty up to two thousand rupees. These steps have obviously reduced the road accidents due to drunk driving to some extent but have not been able to stop it completely. Had the car been smart enough to detect whether the driver is drunk or not and lock its ignition accordingly, accidents due to drunk driving can be rooted completely.

Our system aims to change that with automated, transparent, noninvasive alcohol safety check in vehicles i.e. it aims at making the car smart. For increasing the road safety there is work going on in the development of Intelligent Transportation System (ITS). But these works are not specifically directed in one direction. ITS applies various aspects like information processing, safety, comfort and efficiency of the transportation system. Whereas our system a specific solution to drinking and driving problem. There are devices to detect and avoid a collision. But stopping one of the root causes of collision is obviously much more helpful.

Some works which are related to our system are there. There are projects where PIC 16876A controller, an Alcohol sensor, LCD Display and Alarm system is used to notify driver only. IR LED 894 was used in one of the proposed devices. It produces high-intensity IR ray, which means it absorbs alcohol of only high content from the air, so this mechanism will work only when the driver is over drunk. In one case, it was monitoring the toxic gases such as CO2, LPG, and Alcohol from inside area of the vehicle. If there is a high content of gases then an SMS had been sent to the authorized person to notify only as it did not have any car stopping mechanism. GSM has been used to find the location of the car and send an SMS to the authority. There has been a fatigue monitor prototype. It basically had cameras to take pictures of the driver to learn if the driver is fatigued or not. So it employed image processing to recognize drowsiness of the driver.

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There are many ways in which car locking can be done. The most commonly used security system for a car namely steering wheel lock where locks are placed on the steering wheels. But here a simpler method of ignition locking is being used.

It is found that the existing systems mostly use PIC or AVR microcontrollers for this purpose. But a Raspberry pPi3 runs at 1.2 GHz speed which is faster than other boards like Arduino which has ATmega microcontrollers. Also, it is good for multitasking as the system will have to do many tasks together unlike the available systems.

Here the car, if running, when senses the driver is drunk will automatically stop running and if the car is off, then on sensing the drunken condition of the driver will not allow him to start the car and at the same time sends a SMS to the concerned authority which can be the local traffic police. We have already implemented and tested the system successfully.

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Hardware Components Required

The drunken driving detection system (Road Safety Solution) is implemented using a smart alcohol sensor, portable mini-computer, mobile communication systems. Here all of these parts are integrated to make the smart detection and ignition locking system along with an alerting system which uses the GSM cellular system

i) MQ3 Gas Sensor Module: To detect alcohol in the breath of the driver this module is used. It is a module which is made using an MQ3 gas sensor. This module is a low-cost semiconductor sensor. It can detect the presence of alcohol gases at concentrations from 0.05 mg/L to 10 mg/L. The module has both analog and digital output which gives a huge advantage for interfacing it with different microcontroller boards.

This module is helpful for detecting Ethanol, Benzine, CH4, Hexane, LPG, and CO. This module is very useful in the detection system because of high sensitivity and fast response time. This fast response time can be used to make the measurement as quickly as possible which in turn helps in stopping the car as early as possible. This provides a great performance advantage of the overall system.

The material which is used here for sensing is SnO2. It has a low conductivity in clean air and high conductivity when the concentration of alcohol gas increases in the air. Therefore it increases the current in the output when there is a high alcohol content in the air. The module has an adjustable load resistance the circuit which can be controlled from outside. This variable resistance will help in adjusting the threshold required for operating.  In the module, there is also an LM343 opamp which helps us giving a fixed digital output of 0V or 5V.

MQ3 Module Circuit Diagram
Fig1: MQ3 Module Circuit Diagram

ii) Raspberry Pi 3 model B: This is the main component of the drunken driving detection system. It is a single computer board. It has big advantage of the size which is of the size of a credit-card. It is just like another computer which supports different applications like word processing, gaming, spreadsheets etc. The cost of this computer is very low which helps us in making an overall low-cost solution. Also the lightweight feature of the device also helps in implementing the system as it will be easily integrated inside a vehicle. It has onboard WiFi, Bluetooth and USB boot capability. It uses a Broadcom BCM2837 SoC which has 1.2 GHz 64-bit quad-core ARM Cortex-A53 processor. It also has a 1GB RAM which can help in multi-tasking.

It has 40 General Purpose Input Output (GPIO) pins unlike the previous versions of Raspberry Pi boards which had 28 GPIO pins. Because it is a computer it has its own operating system. The recommended version is Raspbian OS which is used here. Therefore a lot of devices can be interfaced with this computer. It supports different types of coding but popularly python programming is used because of the ease of coding. In this detection system also python programming is used. This board has various advantages over other boards available in the market and one of them is the ease of usability and multi-tasking ability of the board. The voltage output of the Raspberry pi is 0-3.3V.

The raspberry pi takes signals as input from the sensor and makes decisions about the ignition of the vehicle and can stop the vehicle ignition if required as it has the capability to stop the ignition. At the same time, it can send the SMS through a module. As it can take a maximum of 3.3V input so simple resistors can be used to interface it with some components giving 5V as output.

iii) A6 GSM GPRS module: This GSM module is a specialized type of modem. It accepts a SIM card and operates over a mobile operator network. This modem, when connected to a computer, can communicate over the GSM-GPRS network. It requires no special subscription for sending SMS. The operating voltage is 3.3V to 4.2 V. It supports four GSM bands and they are 850, 900, 1800, 1900 MHz. It supports standard GSM AT commands. It has two serial ports, one to transmit and another to receive AT commands. It has 24 pins. It can also be used for voice calls.

There are many other GSM modules in the market but this one of the fastest of all of them. Also, another reason which stands it out is the power consumption which is lower than any other GSM module in the market. The module can be powered up by using only a mobile charger as it has OTP port for power.

Block Diagram of the proposed System
Fig 2: Block Diagram of the Proposed System for Road Safety Solution
Circuit Diagram of the prototype for Road Safety Solution
Fig 3: Circuit Diagram of the prototype for Road Safety Solution

iv) LCD 16×2 Alphanumeric display: It is one of the most popular display device used. This is a 16×2 (16 Characters on 2 lines) LCD with Black font and Yellow Backlight. In this LCD each character is displayed in the 5×7 pixel matrix. There are many readily available libraries for interfacing it with Arduino, Raspberry Pi or other Development Boards and Micro-Controllers/Processors. This can be operated in either 8 Bit or 4 Bit mode of operation. In the 4 Bit mode, it’ll only require 6 Control pins from the Microcontroller. It has an operating voltage of 3.3V-5V. The contrast and brightness of the display can be adjusted using potentiometers or variable resistors.

Fig. 2 shows the block diagram of the drunken driving detection system where the different devices interfaced to the raspberry pi can be seen and how the signal flows from one component to another component is also shown. Fig. 3 is the diagram of an actual prototype circuit of the drunken driving detection system. This prototype has a dc motor in place of a real car for representation purpose. Also, a push-button switch is there to represent the ignition key. This prototype has been implemented and tested successfully in the laboratory.

Fig 4: Flowchart of the code
Fig 4: Flowchart of the code
Fig 5: The prototype circuit for Road Safety Solution
Fig 5: The prototype circuit for Road Safety Solution

Fig. 4 shows the flowchart of the coding. The code is written in python. It can be seen here that the algorithm for the system is very simple. Here the Raspberry pi continuously checks the digital output of the alcohol sensor at a delay of Td=0.5 sec. This is possible due to the high speed of operation of both Raspberry Pi and MQ3 alcohol sensor. The sensor gives a high output when the BrAC exceeds a predetermined threshold. Then the ignition is locked and an SMS text message is sent to the registered mobile number. Here AT commands are used for communicating over the GSM network.  Also at the same time, the driver and vehicle status is shown in the LCD 16×2 alphanumeric display.

Fig. 6. The result of the system showing driver status
Fig. 6a. The result of the system showing driver status
Fig. 6. The result of the system showing driver status
Fig. 6b. The result of the system showing driver status


The prototype of the drunken driving detection with car ignition locking and alerting through SMS has given the results for which it is made. The results are satisfactory as it gives a very fast response to the alcohol content. The fast performance is necessary for avoiding any type of fatality. It also has a high sensitivity to the alcohol content. When the alcohol goes above the threshold level which is predetermined, led in the MQ3 module glows and the ignition is locked. An SMS text message is sent to the registered number and 16×2 LCD module shows that alcohol is detected. The sensing of alcohol and stopping the motor happens within a second of time.

The drunken driver detection system with car ignition lock and alerting system through SMS is a smart system that can stop drunken driving. The system has a high level of accuracy and at the same time, it has fast response. It can detect the drunkenness at two different situations. One is initially at the time of starting the car and the other is when the car is running. Both the time the system has given reliable performance.

The high performance of the system is possible due to two main reasons. One is the Raspberry Pi3 model which has 1.2 GHz processor. Another reason is the A6 GSM module which gives high speed. A6 GSM module is the cheapest GSM module in the market, making the overall system a cheap one. At the same time, it takes only 5V power supply comparing other 12V modems. Therefore the system is also power efficient. Also, it will not cause any unnecessary heating.

This unit can be mounted inside the vehicle very easily due to its small size. If made mandatory by the authority, it can save a lot of lives every year across the globe. The lifetime of the system also matches the average car model lifetime. The low cost of the device is also going to attract a lot of users. This system has the potential to replace the breath analyzer used by the police manually.

Future Scope

This Road Safety Solution has a few future scopes for improvement. One of them is that the message can contain the location of the driver. This can be done using any GPS module available in the market. The other improvement can be the adjustment of the threshold according to the Indian law. One more improvement can be the use a camera to detect drowsiness of a drive.




  1. Can you please send me the code for this project with a working video of the prototype. I have read the above article and this project will be amazing. Even i was thinking of implementing this as my Mini Project. Its an request if you can help me out with this.

  2. Can you please send me the code for this project with a working video of the prototype. I have read the above article and this project will be amazing. Even i was thinking of implementing this as my Mini Project. Its an request if you can help me out with this.

    • can i know why do u want it to do this project ,bcoz it irritates the driver,and also the police officials ,nearly 35% of indians drink alcohol and 25% drink daily,for some reasons ,do u think there are enough police in ur area to stop the drunken people without driving,its practically not possible


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