The RobotDYN MQ4 gas sensor offers strong sensitivity to methane gas and low sensitivity to other gases. An output signal will be produced based on the CH4 concentration that has been measured in the surrounding area. The effectiveness of this sensor in alarm systems, gas detection circuits, coal mines, etc. has been confirmed.

Package Includes:

• 1x RobotDYN MQ4 CH4 Sensor Module

Features:

• Straightforward drive circuit
• Long-lasting & Quick response time
• Inconsequential smoke and alcohol sensitivity
• Has high sensitivity for Methane (CH4)and natural gas
• Wide range coverage.
• Semiconductor type sensor
• More than 24 hour of preheat time
• 20Ω load resistance
• Lower than 95%RH(Related humidity)
• 750 MW ≥ heat consumption
• 14 to 122 degrees Fahrenheit operating temperature
• 1 TTL Compatible interface output (ALR) and 1 TTL compatible interface input (HSW)
• 200ppm to 10000ppm gas detection concentration
• 5V±0.1 VCC power requirement
• 5V and 0.1 DO Output
• 0.1V to 0.3V AO output
• 21% oxygen concentration ( when in standard condition)

Description:

The RobotDYN MQ4 gas sensor offers strong sensitivity to methane gas and low sensitivity to other gases. An output signal will be produced based on the CH4 concentration that has been measured in the surrounding area. The effectiveness of this sensor in alarm systems, gas detection circuits, coal mines, etc. has been confirmed. An AL2O3 micro-ceramic tube, a Tin Dioxide sensitive layer, a measuring electrode, and a heater are fixed into a crust composed of plastic and stainless steel net in the RobotDYN MQ4 gas sensor's structure and design. The heater provides the very bare minimum in terms of working conditions for the usage of fragile components. The sensor is made up of six pins. the other four are used to gather signals, while the other two are there to deliver heating current.

Principle of Work:

The power LED turns on when the module is powered. The MQ-4 operates by detecting the amount of methane in the environment. The sensor's analog pin then provides an analog signal corresponding to the concentration of CH4 in the environment. The majority of MCUs have an integrated ADC that can be used to read the analog output of a methane gas sensor and perform signal processing to transform the observed analog voltage into the amount of methane in the air. We can take the appropriate actions, such as setting off an alarm, based on this measurement. The RobotDYN MQ4 methane sensor's digital output pin is the same. The digital pin turns HIGH and the built-in light for the digital output illuminates when methane gas is detected.

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 gas.

the RobotDYN MQ4 Gas 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. 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:

Environmental Monitoring Systems

The environmental air monitoring system can provide a suitable monitoring method that uses an MQ-4 sensor. This is a lightweight, customer-friendly, and low-cost air monitoring device that can measure Methane gas we can use this anywhere

Methane Testing/Detecting Devices

Through this system, we can immediately collect information on methane, and we can also display other gases which can be processed by any microcontroller, and the results on the OLED display

Gas Leakage Detecting Equipment

The goal of detecting a gas leak is to prevent the worst potential causes of the gas leak, using the above type of MQ sensor. The choice of the MQ-4 sensor is because of the nature of MQ-4 which is suitable for detecting natural gas.

Circuit:

Connect and integrate the RobotDYN MQ4 Gas alcohol Sensor with the Arduino UNO using the circuit shown above. By copying and pasting the code, you may upload it to your Arduino IDE. The next step is to upload the code to the Arduino UNO. watch the readings on the Serial monitor. Take the instrument someplace with CH4to check the abrupt changes in readings. As a result, the adjustments are visible on the serial monitor. and the LED will turn on if the value of the digital out is 1.

Library:

This Module doesn't need any Library to function.

Code:

#define RobotDYN MQ4pin 0
float sensorValue; //variable to store sensor value
void setup() {
 pinMode(13,1);
 Serial.begin(9600); // sets the serial port to 9600
 Serial.println("RobotDYN RobotDYN MQ4 warming up!");
 delay(20000); // allow the RobotDYN RobotDYN MQ4 to warm up
}
void loop() {
 sensorValue = analogRead(RobotDYN RobotDYN MQ4pin); // 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: 5V±0.1
• Heating voltage: 5V±0.1
• Load Resistance: 2K
• Sensing Resistance Range: 10 – 60K
• CH4 Sensing Range: 300 – 10000 ppm
• Sensor Heat Consumption: ≤ 950 mW
• Relative Humidity: >95% RH
• Standard Oxygen concentration: 21%
• Output Analog Voltage: 2.5 – 4 Volts (5000 ppm CH4)
• Preheating Time: Over 48 Hours

Resources:

Tutorial

Tutorial2

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). the RobotDYN MQ4 IS sensing range of 300-10000 PPM is suitable for methane gas leak detection and also for also to Propane and Butane but the MQ5 Sensor can detect LPG (Liquified Petroleum Gas), methane, propane, butane, natural gas and city gas, with low sensitivity to alcohol and smoke so we prefer using MQ5 with gas detections systems in homes.