Automatic exhaust fan control coupled to gas leak detection
ABSTRACT:
Sensitive material of MQ-6 gas sensor is SnO2, which with lower conductivity in clean
air. When the target combustible gas exist, the sensor’s conductivity is more higher along with
the gas concentration rising. Please use simple electro circuit, Convert change of conductivity to
correspond output signal of gas concentration. MQ-6 gas sensor has high sensitity to Propane,
Butane and LPG, also response to Natural gas. The sensor could be used to detect different
combustible gas, especially Methane; it is with low cost and suitable for different application.
Gas leak detection is the process of identifying potentially hazardous gas leaks by means of
various sensors. These sensors usually employ an audible alarm to alert people when a dangerous
gas has been detected. Common sensors used today include Infrared Point Sensor, Ultrasonic gas
detectors, Electrochemical gas detectors, and Semiconductor Sensors. These sensors are used for
a wide range of applications, and can be found in industrial plants, refineries, wastewater
treatment facilities, vehicles, and around the home.
Gas leak detection methods became a concern after the effects of harmful gases on
human health were discovered. Before modern electronic sensors, early detection methods relied
on less precise detectors. Through the 19th and early 20th centuries, coal miners would bring
canaries down to the tunnels with them as an early detection system against life threatening gases
such as carbon dioxide, carbon monoxide and methane. The canary, normally a very songful
bird, would stop singing and eventually die in the presence of these gases, signaling the miners to
exit the mine quickly. Before the development of electronic household carbon monoxide
detectors in the 1980s and 90s, carbon monoxide presence was detected with a chemically
For Details Contact: A.VINAY-9030333433, 0877-2261612
infused paper that turned brown when exposed to the gas. Since then, many technologies and
devices have been developed to detect, monitor, and alert the leakage of a wide array of gases.
In the kitchen where boiling water and cooking produces steam, the cooling steam turns into
water that can cause condensation on walls, ceilings and around windows. When this is
happening on a daily basis, especially during winter, mould and mildew can begin to form which
can have an unpleasant odour but can also be harmful to your health.
In this project we are going to design the circuit to control the exhaust fan speed
automatically according to the temperature in the room. Fan speed control is based on adjusting
the voltage which gets to the fan. Fan speed control has been possible for many decades by using
adjustable power resistors and adjustable transformers. Those methods have been used in movie
theatres, houses and other public places.
For Details Contact: A.VINAY-9030333433, 0877-2261612
Block Diagram:
Power Supply
Gas Sensor
Comparator
Switching Ckt
Exhaust Fan
POWER SUPPLY:
Step Down
T/F
Rectifier
Filter
Voltage
Regulator
For Details Contact: A.VINAY-9030333433, 0877-2261612
ADVANTAGES:
 .To protect from harmful gas leakage.
 .low cast.
 High sensitivity to Propane, Butane and LPG
APPLICATIONS:
 Used in homes an hotels.
 Used in industries.
 It has wide application in various security system
For Details Contact: A.VINAY-9030333433, 0877-2261612