Gas Level Indicator with LEDs using Arduino

 Project Overview:

This project uses an Arduino to monitor gas levels with a gas sensor. Based on the detected gas concentration, different LEDs light up to indicate safe, warning, or dangerous levels of gas in the environment.

Components List:

• Arduino Uno (or compatible)
• 1 x Gas Sensor (e.g., MQ-2)
• 1 x Green LED
• 1 x Yellow LED
• 2 x Red LEDs
• 4 x 220Ω Resistors (for the LEDs)
• Breadboard and Jumper Wires

Circuit Connection:

1. Gas Sensor:

• Connect the analog output pin of the gas sensor to the Arduino’s analog pin A1.

1. LEDs Setup:

• Connect the Green LED to digital pin 7.
• Connect the Yellow LED to digital pin 6.
• Connect the first Red LED to digital pin 5.
• Connect the second Red LED to digital pin 4.
• Place a 220Ω resistor in series with each LED to limit the current.

Project Code:

int PINO_SGAS = A1;         // Pin connected to gas sensor
int LED_VERDE = 7;          // Green LED pin
int LED_AMARELO = 6;        // Yellow LED pin
int LED_VERMELHO1 = 5;      // First Red LED pin
int LED_VERMELHO2 = 4;      // Second Red LED pin

void setup() {
    pinMode(LED_VERDE, OUTPUT);       // Set LED pins as outputs
    pinMode(LED_AMARELO, OUTPUT);
    pinMode(LED_VERMELHO1, OUTPUT);
    pinMode(LED_VERMELHO2, OUTPUT);
}

void loop() {
    int valor = analogRead(PINO_SGAS);    // Read the gas sensor value
    valor = map(valor, 300, 750, 0, 100); // Map sensor value to a percentage (0-100)

    // Control the LEDs based on the mapped value
    digitalWrite(LED_VERDE, HIGH);              // Green LED always on
    digitalWrite(LED_AMARELO, valor >= 30 ? HIGH : LOW);   // Yellow LED on if value >= 30
    digitalWrite(LED_VERMELHO1, valor >= 50 ? HIGH : LOW); // First Red LED on if value >= 50
    digitalWrite(LED_VERMELHO2, valor >= 80 ? HIGH : LOW); // Second Red LED on if value >= 80
    
    delay(250);  // Small delay to prevent flickering
}

Explanation of the Code:

1. Setup Function:

• Configures the LED pins as outputs.

1. Loop Function:

• Reads the analog value from the gas sensor and maps it to a range between 0 and 100.
• The Green LED is always on, indicating the system is running.
• The Yellow LED lights up if the gas level reaches 30% or higher, indicating a warning.
• The first Red LED lights up if the gas level reaches 50% or higher, signaling a potential danger.
• The second Red LED lights up if the gas level reaches 80% or higher, indicating a critical situation.

Summary:

This project is useful in environments where gas leakage detection is critical. The LEDs provide a visual indication of the gas levels, allowing for quick response in case of dangerous concentrations. The setup can be modified for different gas sensors and thresholds depending on the application.