MQ-2, the grove gas sensor is mainly used to detect leakage of gas from home and industry. It can detect different gases like H2, CH4, LPG, CO, alcohol, smoke and propane. It is very fast in taking actions because it has very high sensitivity and very fast response time. It is a metal oxide semiconductor gas sensor and also known as chemiresistor because gas detection is done by measuring change in resistance when gas comes in contact with sensor material. To detect different concentrations of gas, voltage divider network can be used. This sensor works on 5 V DC proper supply. The MQ-2 sensor has total six pins, where four pins are used for signal fetching and two for current conduction.
Sensor consists of two layers of stainless steel known as anti-explosion mesh network. Its role is to ensure that heater element which is inside the sensor does not cause any explosion as sensing process of flammable gases is going on (Figure 9.5).
In air at high temperature, when tin dioxide is heated, oxygen content is absorbed from the surface. Donor electrons are attracted towards oxygen which is absorbed from surface of sensing material in clean air and prevents the flow of electric current.
Applications
- Domestic gas leakage detector
- Industrial combustible gas detector
- Portable gas detector
- Air-quality check
- Gas leakage alarm
- To maintain environment standards in hospitals
Some conditions must be avoided:
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