CogWikiEditor: /* Arduino Program */

2026-10-07T16:00:19Z

Arduino Program

← Older revision		Revision as of 16:00, 7 October 2026
Line 142:		Line 142:
	== Arduino Program ==		== Arduino Program ==

	<~~syntaxhighlight lang="cpp"~~>		<pre>
	const int gasPin = A0;		const int gasPin = A0;
	const int ledPin = 8;		const int ledPin = 8;
Line 182:		Line 182:
	delay(1000);		delay(1000);
	}		}
	</~~syntaxhighlight~~>		</pre>

	== Code Explanation ==		== Code Explanation ==

CogWikiEditor: Created page with " = Experiment: Gas Leakage Detection Using Arduino UNO = == Aim == To develop a gas leakage detection application using an Arduino UNO and an MQ-2 gas sensor to monitor the surrounding environment and generate an alert when the sensor reading exceeds a predefined threshold. == Objectives == * To understand the working principle of the MQ-2 gas sensor. * To interface a gas sensor with the Arduino UNO. * To read analog sensor values using the ADC of the Arduino. * To i..."

2026-10-02T14:39:07Z

Created page with " = Experiment: Gas Leakage Detection Using Arduino UNO = == Aim == To develop a gas leakage detection application using an Arduino UNO and an MQ-2 gas sensor to monitor the surrounding environment and generate an alert when the sensor reading exceeds a predefined threshold. == Objectives == * To understand the working principle of the MQ-2 gas sensor. * To interface a gas sensor with the Arduino UNO. * To read analog sensor values using the ADC of the Arduino. * To i..."

New page

= Experiment: Gas Leakage Detection Using Arduino UNO =

== Aim ==

To develop a gas leakage detection application using an Arduino UNO and an MQ-2 gas sensor to monitor the surrounding environment and generate an alert when the sensor reading exceeds a predefined threshold.

== Objectives ==

* To understand the working principle of the MQ-2 gas sensor.
* To interface a gas sensor with the Arduino UNO.
* To read analog sensor values using the ADC of the Arduino.
* To implement threshold-based gas detection.
* To activate an alert using an LED and buzzer when the sensor reading exceeds the set threshold.

== Components Required ==

{| class="wikitable"
|-
! Sr. No.
! Component
! Quantity
|-
| 1
| Arduino UNO Development Board (COG-U1)
| 1
|-
| 2
| MQ-2 Gas Sensor (COG-MSBA)
| 1
|-
| 3
| LED bar
| 1
|-
| 4
| Buzzer
| 1
|-
| 5
| USB data cable
| 1
|-
| 6
| Patch cords
| As required
|-
| 7
| Computer with Arduino IDE
| 1
|}

== Theory ==

=== Gas Leakage Detection ===

Gas leakage detection is an important application in homes, industries, laboratories, and other environments where combustible gases may be present. A gas sensor detects changes in the surrounding gas concentration and generates an electrical signal that can be processed by a microcontroller.

=== MQ-2 Gas Sensor ===

The MQ-2 is a semiconductor gas sensor commonly used for detecting combustible gases and smoke. It is sensitive to gases such as LPG, propane, methane, hydrogen, and smoke.

The sensor contains a sensing element whose electrical resistance changes in the presence of certain gases. The sensor module converts this change into an electrical output.

Common MQ-2 module interfaces include:

* '''VCC:''' Power supply input.
* '''GND:''' Ground connection.
* '''AO:''' Analog output voltage related to the sensor response.
* '''DO:''' Digital output from an onboard comparator, often with an adjustable threshold.

In this experiment, the analog output is used to read sensor values through the Arduino UNO's analog input.

=== Analog-to-Digital Conversion ===

The Arduino UNO has a 10-bit analog-to-digital converter (ADC). The analogRead() function converts the analog input voltage into a digital value ranging from 0 to 1023 when using the default reference.

=== Threshold-Based Detection ===

The Arduino continuously reads the analog output of the MQ-2 sensor. The measured value is compared with a predefined threshold.

* If the sensor reading is below the threshold, the system indicates normal operation.
* If the sensor reading is equal to or above the threshold, the system activates the alert LED and buzzer.

The threshold used in this experiment is a demonstration value and must be adjusted based on actual sensor readings. It does not represent a calibrated gas concentration.

== Pin Connections ==

{| class="wikitable"
|-
! Arduino UNO Pin
! MQ-2 / Output Connection
! Description
|-
| 5V
| MQ-2 VCC
| Sensor power supply
|-
| GND
| MQ-2 GND
| Common ground
|-
| A0
| MQ-2 AO
| Analog sensor output
|-
| D8
| LED bar input
| Visual alert output
|-
| D9
| Buzzer input
| Audible alert output
|}

'''Note:''' These connections assume that the MQ-2 board exposes an analog output compatible with the Arduino UNO and that the LED bar and buzzer accept active-HIGH digital control. Verify the actual pin labels and interface of your Cognifront sensor and output boards before connecting.

== Connection Diagram ==

<pre>
MQ-2 Gas Sensor
+---------------+
| |
| VCC ---------+---- 5V
| GND ---------+---- GND
| AO ---------+---- A0
+---------------+

Arduino UNO
+------------------+
| |
| A0 <--- MQ-2 AO |
| |
| D8 ------------+---- LED Bar Input
| |
| D9 ------------+---- Buzzer Input
| |
| GND ------------+---- Common GND
+------------------+
</pre>

== Arduino Program ==

<syntaxhighlight lang="cpp">
const int gasPin = A0;
const int ledPin = 8;
const int buzzerPin = 9;

// Demonstration threshold; calibrate for your setup
const int gasThreshold = 400;

int gasValue = 0;

void setup() {
Serial.begin(9600);

pinMode(ledPin, OUTPUT);
pinMode(buzzerPin, OUTPUT);

digitalWrite(ledPin, LOW);
digitalWrite(buzzerPin, LOW);

Serial.println("MQ-2 Gas Detection System");
}

void loop() {
gasValue = analogRead(gasPin);

Serial.print("Gas Sensor Value: ");
Serial.println(gasValue);

if (gasValue >= gasThreshold) {
digitalWrite(ledPin, HIGH);
digitalWrite(buzzerPin, HIGH);
Serial.println("WARNING: Gas level threshold exceeded!");
} else {
digitalWrite(ledPin, LOW);
digitalWrite(buzzerPin, LOW);
Serial.println("Status: Normal");
}

delay(1000);
}
</syntaxhighlight>

== Code Explanation ==

{| class="wikitable"
|-
! Statement
! Description
|-
| const int gasPin = A0;
| Defines analog pin A0 as the gas sensor input.
|-
| const int ledPin = 8;
| Defines digital pin D8 as the LED control output.
|-
| const int buzzerPin = 9;
| Defines digital pin D9 as the buzzer control output.
|-
| const int gasThreshold = 400;
| Sets a demonstration threshold for gas detection.
|-
| analogRead(gasPin)
| Reads the analog output of the gas sensor and returns a value from 0 to 1023.
|-
| Serial.println(gasValue)
| Displays the sensor reading on the Serial Monitor.
|-
| if (gasValue >= gasThreshold)
| Checks whether the sensor reading has reached or exceeded the threshold.
|-
| digitalWrite(ledPin, HIGH)
| Activates the LED alert output.
|-
| digitalWrite(buzzerPin, HIGH)
| Activates the buzzer alert output.
|-
| delay(1000)
| Pauses the program for one second before the next reading.
|}

== Procedure ==

# Connect the MQ-2 sensor's VCC and GND pins to the Arduino UNO's 5V and GND, respectively.
# Connect the sensor's analog output (AO) to the Arduino analog input A0.
# Connect the LED bar input to D8 and the buzzer input to D9, ensuring that the output interfaces are compatible.
# Connect the Arduino UNO to the computer using the USB data cable.
# Open the Arduino IDE and select the Arduino UNO board and appropriate COM port.
# Enter the program and upload it to the Arduino UNO.
# Open the Serial Monitor and set the baud rate to 9600.
# Allow the MQ-2 sensor to warm up and stabilize according to its datasheet and module instructions.
# Observe the sensor readings under the available ambient conditions.
# Adjust the demonstration threshold based on observed readings, if required.
# Observe the LED and buzzer response when the reading crosses the configured threshold.

'''Safety precaution:''' Do not intentionally release LPG, lighter gas, smoke, or other combustible gases to test the circuit. This is an educational demonstration, not a certified gas alarm or safety system. Conduct any controlled sensor testing only with appropriate laboratory safety procedures.

== Observations ==

{| class="wikitable"
|-
! Sr. No.
! Sensor Reading
! Condition
! LED
! Buzzer
|-
| 1
| Below threshold
| Normal
| OFF
| OFF
|-
| 2
| Equal to or above threshold
| Threshold exceeded
| ON
| ON
|}

The readings and alert response should be recorded during the experiment. The table describes expected behavior, not measured results.

== Result ==

An Arduino UNO-based gas detection demonstration was developed using an MQ-2 sensor. The sensor's analog output was read and compared against a predefined threshold. An LED and buzzer were programmed to provide alerts when the reading exceeded the threshold.

== Viva Questions ==

# What is the purpose of a gas sensor?
# What is the working principle of the MQ-2 sensor?
# Which gases can the MQ-2 sensor detect?
# What is the difference between the analog and digital outputs of an MQ-2 module?
# What is the resolution of the Arduino UNO ADC?
# What is the purpose of the analogRead() function?
# Why is a threshold used in gas detection?
# Why does an MQ-2 sensor require a warm-up period?
# Can an MQ-2 sensor directly measure gas concentration in parts per million without calibration?
# What are the limitations of a threshold-based gas detection system?
# How can this project be extended to send gas alerts through an IoT cloud platform?

MDM331AID/Experiment 4 - Revision history

CogWikiEditor: /* Arduino Program */