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MQ 7 Carbon Monoxide Sensor Module (HCSENS0023) 
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Post MQ 7 Carbon Monoxide Sensor Module (HCSENS0023)
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The MQ-7 carbon monoxide sensor module allows for the sensing of CO concentrations in the air. This module can detect CO gas concentrations from anywhere between 20 and 2000ppm.

The sensor is highly sensitive and has a quick response time. It uses analogue resistance as an output and is extremely easy to connect with the use of Arduino.

Please note: This module has an adjustable sensitivity and is not calibrated.




Pinout
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Technical Data
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Schematic
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CONDITIONS TO AVOID
The following conditions must be avoided in order to maintain optimum working conditions for the sensor and also to avoid invalid readings from the sensor.

Exposure to organic silicon steam, silicon bond, fixature, silicon latex, putty or plastic containing silicon.

High Corrosive gas. If the sensor is exposed to high concentrations of corrosive gas (such as H2Sz, SOX,Cl2,HCl etc), it will not only result in corrosion of the sensors structure, but will also cause sincere sensitivity attenuation.

Alkali, Alkali metal salt, halogen pollution as the sensors performance will be changed badly if the sensor is sprayed and thus polluted by alkali metal salt, especially brine, or be exposed to halogen such as fluorin.

Water. The high sensitivity of the sensors will be reduced if it becomes wet or is emerged in water.

Freezing. Avoid ice coming into contact with the sensors surface. This can cause the sensor to lose sensitivity.

Voltage. Be sure that the applied voltage is correct as overloading the sensor will cause damage and may potentially damage the sensor irreparably.

Connections. Avoid applying voltage to the wrong pins. A correct pinout can be seen above.




Example Arduino Sketch

Code:
/* FILE:    MQ7_Carbon_Monoxide_Sensor_Module_Example
   DATE:    18/08/16
   VERSION: 0.1

This is a simple example of how to use the Hobby Components MQ-7 Carbon Monoxide Sensor 
module.

SENSOR PINOUT:
PIN 1: VCC
PIN 2: GND
PIN 3: Digital Out
PIN 4: Analogue Out

You may copy, alter and reuse this code in any way you like, but please leave
reference to HobbyComponents.com in your comments if you redistribute this code.
This software may not be used directly for the purpose of selling products that
directly compete with Hobby Components Ltd's own range of products.

THIS SOFTWARE IS PROVIDED "AS IS". HOBBY COMPONENTS MAKES NO WARRANTIES, WHETHER
EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ACCURACY OR LACK OF NEGLIGENCE.
HOBBY COMPONENTS SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR ANY DAMAGES,
INCLUDING, BUT NOT LIMITED TO, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES FOR ANY
REASON WHATSOEVER.

/* Selects the input pin for the sensors analogue output. */
#define MQ7_ANA_OUT A0     
                                 
/* Selects the input pin for the sensors digital output. */
#define MQ7_DIG_OUT_DIO 2       
                                 


/* Initialises serial and DIO */
void setup()
{
  /* Sets up the serial port for displaying the status of the sensor */
  Serial.begin(9600);
 
  /* Configures the DIO pin the sensors digital output will be connected to */
  pinMode(MQ7_DIG_OUT_DIO, INPUT);
}


/* Main program loop */
void loop()
{
  /* Reads the sensors analogue output and sends it to the serial port */
  Serial.print("Sensor Value: ");
  Serial.print(analogRead(MQ7_ANA_OUT));
 
  /* Reads the status of the sensors digital output and if it is high
     then sends an alert to the UART */
  if (digitalRead(MQ7_DIG_OUT_DIO))
  {
    Serial.println(" LEVEL TRIGGERED!");
  }else
  {
    Serial.println();
  }
   
}




Disclaimer: Libraries, example code, and diagrams are provided as an additional free service by Hobby Components and are not sold as part of this product. We do no provide any guarantees or warranties as to their accuracy or fitness for purpose.

Descriptions and diagrams on this page are copyright Hobby Components Ltd and may not be reproduced without permission.


Wed Aug 17, 2016 2:36 pm
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