MQ-8 Gas Sensor Module Documentation
The MQ-8 Gas Sensor Module is a highly sensitive and reliable gas detector module designed to detect hydrogen gas concentrations in the air. This module is based on the MQ-8 gas sensor, which is a tin dioxide (SnO2) semiconductor sensor. The module provides an analog output that varies proportionally to the concentration of hydrogen gas present in the environment.
The MQ-8 Gas Sensor Module has the following pinout:
| Pin | Function |
| --- | --- |
| VCC | Power Supply (5V) |
| GND | Ground |
| OUT | Analog Output |
The MQ-8 gas sensor detects hydrogen gas by measuring the changes in resistance that occur when the gas comes into contact with the sensor's surface. The sensor's resistance decreases in the presence of hydrogen gas, causing the output voltage to increase.
### Example 1: Basic Analog Reading using Arduino
In this example, we will connect the MQ-8 Gas Sensor Module to an Arduino board and read the analog output using the `analogRead()` function.
```cpp
const int sensorPin = A0; // Connect the OUT pin of the MQ-8 module to Analog Input A0 on the Arduino board
void setup() {
Serial.begin(9600);
}
void loop() {
int sensorValue = analogRead(sensorPin);
float voltage = sensorValue (5.0 / 1023.0);
Serial.print("Analog Output: ");
Serial.print(voltage);
Serial.println(" V");
delay(500);
}
```
### Example 2: Hydrogen Gas Detection using Raspberry Pi and Python
In this example, we will connect the MQ-8 Gas Sensor Module to a Raspberry Pi board and use Python to read the analog output using the `RPi.GPIO` library.
```python
import RPi.GPIO as GPIO
import time
# Set up GPIO library
GPIO.setmode(GPIO.BCM)
# Define the MQ-8 module's OUT pin as an input
sensorPin = 17
GPIO.setup(sensorPin, GPIO.IN)
try:
while True:
# Read the analog output using the ADC converter
reading = GPIO.input(sensorPin)
voltage = reading (5.0 / 1023.0)
print("Analog Output: {:.2f} V".format(voltage))
time.sleep(0.5)
except KeyboardInterrupt:
# Clean up GPIO on exit
GPIO.cleanup()
```
### Example 3: MQ-8 Gas Sensor Module with LCD Display using ESP32 and MicroPython
In this example, we will connect the MQ-8 Gas Sensor Module to an ESP32 board and use MicroPython to read the analog output and display the hydrogen gas concentration on an LCD display.
```python
import machine
import utime
# Set up the LCD display
lcd = machine_LCD.LCD(22, 21, 18, 19, 23, 5)
# Define the MQ-8 module's OUT pin as an analog input
sensorPin = machine.ADC(machine.Pin(32))
while True:
# Read the analog output
sensorValue = sensorPin.read()
voltage = sensorValue (5.0 / 4095.0)
gasConcentration = voltage 1000 # Convert voltage to gas concentration (ppm)
# Display the gas concentration on the LCD
lcd.fill(0)
lcd.text("Hydrogen Gas Concentration:", 0, 0)
lcd.text("{:.2f} ppm".format(gasConcentration), 0, 1)
lcd.show()
Note: In these examples, the analog output voltage is assumed to be directly proportional to the hydrogen gas concentration. However, in a real-world application, you may need to calibrate the sensor and convert the analog output to a meaningful gas concentration value using a calibration curve or formula specific to your environment and use case.
