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Complete features and working of mq-6

http://www.engineersgarage.com/contribution/gsm-based-industrial-automation?page=11

with all CODE information about mq-2 and mq-6 connections and features

http://www.thaieasyelec.com/Review-Product-Article/Gas-Sensor-Getting-Started.html

MQ-2

http://www.technobotsonline.com/flammable-gas-and-smoke-sensor-mq-2.html

Overview

This flammable gas and smoke sensor from Pololu detects the concentrations of combustible gas in the air and ouputs its reading as an analog voltage. The sensor can measure concentrations of flammable gas of 300 to 10,000 ppm.The sensor can operate at temperatures from -20 to 50°C and consumes less than 150 mA at 5 V. Please read the MQ-2 datasheet (184k pdf) below for more information about the sensor.

Feature- Power requirements: 5 VDC @ ~160mA- Interface Type: Resistive- Dimensions: 0.75" diameter x 0.65" tall excluding leads (19.1mm diameter x 16.55mm tall excluding leads)- Operating temp range: -4 to +122 °F (-20 to +50 °C)

Connections

Connecting five volts across the heating (H) pins keeps the sensor hot enough to function correctly. Connecting five volts at either the A or B pins causes the sensor to emit an analog voltage on the other pins. A resistive load between the output pins and ground sets the sensitivity of the detector. Please note that the picture in the datasheet for the top configuration is wrong. Both configurations have the same pinout consistent with the bottom configuration.The resistive load should be calibrated for your particular application using the equations in the datasheet, but a good starting value for the resistor is 20 kOhms.

We offer breakout boards that make it easier to interface with these sensors, see related products links below.

MQ-6

http://www.technobotsonline.com/lpg-isobutane-propane-gas-sensor-mq-6.html

Overview

This propane gas sensor detects the concentrations of LPG, isobutane, and propane in the air and ouputs its reading as an analog voltage. The sensor can measure concentrations of 300 to 10,000 ppm.The sensor can operate at temperatures from -10 to 50°C and consumes less than 150 mA at 5 V. Please read the MQ-6 datasheet (178k pdf) below for more information about the sensor.

Connections

Connecting five volts across the heating (H) pins keeps the sensor hot enough to function correctly. Connecting five volts at either the A or B pins causes the sensor to emit an analog voltage on the other pins. A resistive load between the output pins and ground sets the sensitivity of the detector. Please note that the picture in the datasheet for the top configuration is wrong. Both configurations have the same pinout consistent with the bottom configuration.The resistive load should be calibrated for your particular application using the equations in the datasheet, but a good starting value for the resistor is 20 kOhms.

We offer breakout boards that make it easier to interface with these sensors, see related products links below.

http://wineyard.in/academics/major-projects

Re: MQ2 gas/smoke sensor

// int room[] = { 1,2,3,4,5,6 };int room[] = { 7,8,9,10,11,12 };

void setup(){  Serial.begin(115200);  Serial.begin("Smoke monitor");}

void loop(){  for (Int i = 0; i< 6; i++)  {     int x = analogRead(i);     if (x < 500 || x > 700)      {        Serial.print("Battery low in room ");        Serial.println( room[i] );        // doBUZZ();

     }     delay(100);  }}

Air Quality MQ135 sensor similar to gas sensor

int sensorValue;

void setup(){ Serial.begin(9600); // sets the serial port to 9600}

void loop(){ sensorValue = analogRead(0); // read analog input pin 0 Serial.println(sensorValue, DEC); // prints the value read delay(100); // wait 100ms for next reading}

air quality measured by the sensor. The value read is printed to the serial monitor

Sensor calibration

Get the maximum and minimum value from a sensor to help finding its operation range at current conditions. Any analog sensor, (photoresistor or potentiometer) connected to analog pin 0 will be fine.int sensorValue = 0; // The sensor valueint sensorMin = 1023; // Minimum sensor valueint sensorMax = 0; // Maximum sensor value

void setup(){ Serial.begin(9600); // Open the serial at 9600 Serial.println("Starting calibration for 10 seconds"); // calibrate during the first five seconds

while (millis() < 10000) { sensorValue = analogRead(0); // read sensor connected to analog pin 0

if (sensorValue > sensorMax) // save the maximum sensor value found { sensorMax = sensorValue; }

if (sensorValue < sensorMin) // save the minimum sensor value found { sensorMin = sensorValue; } } Serial.println("Finished calibration");}

void loop(){ // read sensor connected to analog pin 0 sensorValue = analogRead(0);

// use the calibration to print values between 0 and 100 sensorValue = map(sensorValue, sensorMin, sensorMax, 0, 100);

// keep the value in the desired range sensorValue = constrain(sensorValue, 0, 100);

// fade the LED using the calibrated value: Serial.println(sensorValue, DEC);}

http://www.dfrobot.com/wiki/index.php?title=Analog_Gas_Sensor%28MQ2%29_%28SKU:SEN0127%29

Description :

MQ-2  Semiconductor Sensor for Combustible Gas

Sensitive material of MQ-2 gas sensor is SnO2, which with lower conductivity in clean air. When the target combustible gas exist, The sensors conductivity is more higher along with the gas concentration rising. Please use simple electrocircuit, Convert change of conductivity to correspond output signal of gas concentration.

MQ-2 gas sensor has high sensitity to LPG, Propane and Hydrogen, also could be used to Methane and other combustible steam, it is with low cost and suitable for different application. Character :

1、High sensitivity to Combustible gas in wide range

2、High sensitivity to LPG, Propane and Hydrogen

3、Fast response

4、Wide detection range

5、Stable performance、long life、low cost    

6、Simple drive circuit

Application :                      

1)  Domestic gas leakage detector

2)  Industrial Combustible gas detector

3)  Portable gas detector

4)  They are used in gas leakage detecting equipments in family and industry, are suitable for detecting of LPG, i-butane, propane, methane ,alcohol, Hydrogen, smoke.

http://www.dfrobot.com/wiki/index.php/Analog_Gas_Sensor%28MQ2%29_%28SKU:SEN0127%29

http://microcontrollershop.com/product_info.php?products_id=5510