{"id":81297,"date":"2024-06-25T23:50:05","date_gmt":"2024-06-26T03:50:05","guid":{"rendered":"https:\/\/www.engineersgarage.com\/?p=81297"},"modified":"2024-06-19T12:20:06","modified_gmt":"2024-06-19T16:20:06","slug":"how-to-build-an-alcohol-detector-with-the-mq3-gas-sensor","status":"publish","type":"post","link":"https:\/\/www.engineersgarage.com\/how-to-build-an-alcohol-detector-with-the-mq3-gas-sensor\/","title":{"rendered":"How to build an alcohol detector with the MQ3 gas sensor"},"content":{"rendered":"

Depending on the country, as many as 25 to 35% of motor vehicle accidents happen because of drunk driving every year. When drivers consume alcohol, they not only put themselves at risk but others on the road. Fortunately, such accidents are preventable <\/span>with a combination of<\/span> education, personal responsibility, and community efforts.<\/span><\/p>\n

There are also systems that can<\/span> provide additional support. We\u2019ll build one in this project.<\/span><\/p>\n

This circuit design includes an alcohol detection device with an engine locking system. It uses the property of conductivity in an MQ3 alcohol gas sensor.<\/span><\/p>\n

Working principle<\/span><\/strong><\/h3>\n

The MQ3 alcohol gas sensor is developed from a material called <\/span>SnO2<\/span><\/strong>, which detects alcohol gas. Connecting it to a microcontroller makes it possible to register the SnO2\u2019s change in voltage output in the presence of alcohol. Thanks to a relay, a vehicle\u2019s motor will automatically shut off based on the data from this sensor.<\/span><\/p>\n

Block diagram<\/span><\/strong><\/p>\n

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Figure 1.<\/strong> Block diagram<\/p><\/div>\n

Materials<\/h3>\n
    \n
  1. Arduino UNO (or a similar microcontroller board)<\/li>\n
  2. MQ-3 alcohol sensor<\/li>\n
  3. 5V relay<\/li>\n
  4. LED<\/li>\n
  5. Buzzer<\/li>\n
  6. BC547 transistor<\/li>\n
  7. Dual-shaft dc geared Mmotor 100 RPM<\/li>\n
  8. Pushbutton switch<\/li>\n
  9. Power supply (9-V battery or dc adapter)<\/li>\n
  10. Breadboard and jumper wires<\/li>\n
  11. Connecting cables<\/li>\n<\/ol>\n

    Circuit diagram<\/strong><\/h3>\n

     <\/p>\n

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    Figure 2.<\/strong> The circuit diagram of the alcohol detection system using an MQ3 gas sensor.<\/p><\/div>\n

    Step-by-step guide<\/strong><\/h3>\n

    Step 1. The components
    \n<\/strong>First gather all of the required materials and components. <\/span>Set up the Arduino UNO on a breadboard and connect the MQ-3 alcohol sensor, the relay module, and the switch according to the circuit diagram.<\/p>\n

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    Figure 3.\u00a0<\/strong> The alcohol sensor connections.<\/p><\/div>\n

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    Figure 4.<\/strong> The LED and buzzer connections.<\/p><\/div>\n

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    Figure 5.<\/strong> The transistor circuit connections.<\/p><\/div>\n

    Step 2. Program Arduino<\/strong><\/p>\n