Alcohol Detector circuit using IC-555

Alcohol Detector

Alcohol Detector is used to sense alcohol. In this project if driver drive the vehicle by drinking alcohol then from speaker siren type sound is listen for information to the passenger. By this project we try to avoid accident which is created by drunken alcohol.

Use this simple circuit to detect the presence of Alcohol. This kind circuit is used by Police officials to prevent drunk driving. It gives a beep when it detects the Alcohol vapor. MQ3 Alcohol sensor is now readily available and you can make the device very easily. When the Sensor detects alcohol vapor, it gives output voltage depending on the concentration of alcohol molecules in the air.

Alcohol Detector Circuit:

BD_Alcohol detector
BD_Alcohol detector


It is use to sense alcohol smell and converted it into the corresponding electrical signal.


It is use to drive negative supply of siren circuit.


It is use to generate astable frequency like ambulance siren and that is connect to the speaker. It generate astable frequency like ambulance siren IC555 is use.


It is use to convert electrical signal obtain from ambulance siren circuit.

IC 555

General Description

The operation of SE/NE 555 timer directly depends on its internal function. The three equal resistors R1, R2, R3 serve as internal voltage divider for the source voltage. Thus one-third of the source voltage VCC appears across each resistor.



Alcohol Sensor Is Used To Detect Weather The Person Have Consumed The Alcohol Or Not. The Sensor Which We Have Used Is Mq3 Sensor. This Sensor Is An Analog Sensor And The Output Is In Analog Form.

Sensitive Material Of Mq-3 Gas Sensor Is Sno2, Which With Lower Conductivity In Clean A. When The Target Alcohol Gas Exist, The Sensor’s Conductivity Is More Higher Along With The Gas Concentration Rising.


ØBurglar alarm system

ØSmoke and fire alarm system

ØGarage door controllers

ØCar door controllers

ØCar alarm system

ØSecurity system

ØCordless telephones

ØOther remote control systems

Power Supply

The project requires a regulated 5 volt supply voltage. The circuit shown in Figure converts an unregulated supply of 9 volts to 5 volts for use.


Successfully built alcohol sensor project using IC-555.

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