The RobotDYN MQ3 alcohol sensor is sensitive to a variety of gases in addition to alcohol, like benzine, hexane, or LPG in the air. it is most frequently used as a breathalyzer (breath analyzer) for those who have ingested alcohol such as beer, wine, or other alcoholic beverages.

Package Includes:

• 1x RobotDYN MQ3 Alcohol Sensor Module

Features:

• The RobotDYN MQ3 alcohol sensor operates on 5V DC and consumes approximately 800mW. 
• Can Measure or detect Alcohol, benzine, hexane, or LPG
• Analog output voltage: 0V to 5V
• Digital Output Voltage: 0V or 5V (TTL Logic)
• Preheat duration 20 seconds
• Can be used as a Digital or analog sensor
• It can vary the Sensitivity of the Digital pin using the potentiometer
• Wide detecting Scope
• Fast response and High sensitivity
• Stable and long life Simple drive circuit
• detects the concentration of alcohol 25 to 500 ppm in the air
• If the sensor has recently been used, it will only take 5-10 minutes to fully warm up.
• When first used after a long period of storage (a month or more), the sensor must be fully warmed up for 24-48 hours to ensure maximum accuracy.

Description:

The RobotDYN MQ3 alcohol sensor is sensitive to a variety of gases in addition to alcohol, like benzine, hexane, or LPG in the air. the MQ3 alcohol sensor is most frequently used as a breathalyzer (breath analyzer) for those who have ingested alcohol such as beer, wine, or other alcoholic beverages. The RobotDYN MQ3 alcohol sensor, according to the datasheet, detects alcohol concentrations between 25 and 500 parts per million (ethane). Devices that are used as breath checkers to determine blood alcohol concentration are generally referred to as breathalyzers.

Principle of Work:

A heating element is necessary for the RobotDYN MQ3 gas sensor to effectively recognize Alcohol. Alcohol and hot elements should not be placed next to each other. In order to prevent explosions, the Sensor is constructed with two thin layers of stainless steel mesh. A heating element is built into this stainless steel mesh. In addition to shielding against dust and other suspended particles, this mesh structure also allows only gaseous elements from the environment to pass through. The sensor has two main parts, as can be seen when we disassemble it. The first one is a heating element made of nichrome wire, while the second one is a detecting element made of platinum wire that has been coated in tin dioxide. Alcohol Sensor RobotDYN MQ3 Requires Calibration The calibration of the RobotDYN MQ3 sensor may wonder if it is kept in storage for a long time because it is a heater-driven sensor. The sensor must be properly warmed up for 24-48 hours before usage following a lengthy period of storage (a month or more) in order to ensure maximum accuracy. If the sensor has recently been used, it will warm up completely within 5–10 minutes. The sensor normally reads high during the warm-up phase before progressively falling until it stabilizes. only if you want a precise measurement of the alcohol concentration is the 48-hour warm-up period necessary. Additionally, you'll require a reliable sensor calibration as well as a method for accounting for other environmental factors like temperature, humidity, and so on.

Pinout of the Module:

Pin Name	Description
VCC	supplies power for the module. You can connect it to 5V output from your Arduino.
GND	is the Ground Pin and needs to be connected to the GND pin on the Arduino.
D0	provides a digital representation of the presence of combustible gases.
A0	provides analog output voltage is proportional to the concentration of smoke/gas.

the RobotDYN MQ3 Gas and Smoke Sensor Module has 4 pins, two of which are for VCC and Gnd and the other two can output analog and digital data simultaneously. The module's working voltage range is 5V with a tolerance of 0.1%, so we are powering the circuit using the Arduino's 5V port. As can be seen in the image above, the module features two internal LEDs. The power LED turns on when the board is powered up, and the doubt LED turns on when the trigger value set by the potentiometer is reached. The analog signal from the gas sensor's input is converted to a digital signal on this board by the integrated comparator OP-Amp. We also have a Trim-pot that enables us to adjust the sensitivity of the device. We also have a number of resistor capacitors for decoupling and filtering.

Applications:

• Gas level over-limit alarm
• Breathalyzer
• Portable alcohol detector
• Stand-alone/background sensing device
• Environmental monitoring equipment

Circuit:

Using the above circuit, connect and interface the MQ3 Gas alcohol Sensor with the Arduino UNO. upload the code on your Arduino IDE by copying and pasting it. Upload the code into the Arduino UNO after that. observe the Serial monitor's readings. Take the device somewhere smokey to look at the sudden variations in readings. The modifications are consequently visible on the serial monitor. and if the value of the digital out is 1 the LED will light up.

Library:

This Module doesn't need any Library to function.

Code:

#define MQ3pin 0

float sensorValue;  //variable to store sensor value

void setup() {
  pinMode(13,1);
  Serial.begin(9600); // sets the serial port to 9600
  Serial.println("MQ3 warming up!");
  delay(20000); // allow the MQ3 to warm up
}

void loop() {
  sensorValue = analogRead(MQ3pin); // read analog input pin 0

  Serial.print("Sensor Value: ");
  Serial.println(sensorValue);
  if(digitalRead(8)){
    digitalWrite(13,1);
  }else{
        digitalWrite(13,0);

  }
  
  delay(2000); // wait 2s for next reading
}

Technical Details:

Operating Voltage	4.9-5.1V
Detecting Concentration	0.05-10mg/L
Current Consumption	150mA
DO Output	TTL digital 0 and 1
AO Output	0.1-0.3V
Load Resistance	200kΩ
Heater Resistance	33Ω
Heater Consumption	less than 750mW
Operating Temperature	-10 to 50°C
Dimensions:	36 x 20 x 21 mm (LxWxH)
Heater voltage:	5±0.2V (AC•DC)
Weight:	6gm

Resources:

 

Comparisons:

The MQ series Gas sensors are the most frequently used ones when it comes to measuring or detecting a specific Gas. Both the sensor and the module for these sensors are available for purchase. Since it includes an op-amp comparator and a digital out pin, you can purchase it as a module if all you're trying to do is detect the presence of a gas rather than measure its ppm. But it is advised to purchase the sensor alone if you intend to monitor a gas' ppm levels (without module). but as you see the sensor is sensitive to all these kinds of these gases, the MQ2 is somehow equivalent to the RobotDYN MQ3  in some gases ( Benzine, CH₄, Hexane, LPG, CO.) if want the sensor to be more sensitive to the alcohol then stay with RobotDYN MQ3 if you want to be more sensitive to CO2 - CO MQ2 is your choice