MQ 3 Gas Sensor Module

 MQ 3 gas sensor module is designed to detect the presence of alcohol vapors in the air. Here’s a detailed description:

Working Principle:

The MQ 3 gas sensor module is a metal oxide semiconductor (MOS) type sensor, also known as a chemiresistor. It contains a sensing material, typically tin dioxide (SnO2), which changes its resistance when exposed to alcohol vapors. When the sensor is heated, oxygen molecules adsorb on the surface of the sensing material3. In the presence of alcohol vapors, these oxygen molecules react with the alcohol, reducing the surface density of adsorbed oxygen and allowing current to flow through the sensor. The resulting analog voltage values are measured to determine the concentration of alcohol vapors3.

Operating Voltage: 5V DC

Detection Range: 25-500 ppm (parts per million)

Output: Analog voltage (0-5V) and digital output (TTL logic)

Preheat Duration: Approximately 20 seconds

Sensitivity: Can be adjusted using a potentiometer

Breathalyzers: Detecting alcohol levels in breath for DUI checks.

Gas Leak Detection: Used in homes and industries to detect alcohol leaks.

Environmental Monitoring: Monitoring air quality in various environments.

Safety Systems: Ensuring safety in sensitive environments like laboratories.

Non-Specific: The MQ-3 sensor cannot distinguish between different gases; it only detects their presence.

Accuracy: While effective for detecting gas presence, it is not suitable for precise measurement of gas concentrations without additional calibration