API for the MQ7 CO Gas Sensor. More...

Detailed Description

ID: mq7
Name: MQ7 Carbon Monoxide Sensor
Category: gaseous
Manufacturer: dfrobot
Connection: analog
Link: https://www.dfrobot.com/wiki/index.php/Carbon_Monoxide_Gas_Sensor(MQ7)_(SKU:SEN0132)

The Grove MQ7 Gas Sensor module is useful for detecting Carbon Monoxide (CO) concentrations in the air. It has a detection range of 20-2000 ppm.

For optimum use, it requires calibration after a pre-heat time of 48 hours. See the datasheet for details.

int main(int argc, char **argv)
{
  // Attach gas sensor to Analog A0
  upm::MQ7 *sensor = new upm::MQ7(0);
  signal(SIGINT, sig_handler);
  
  uint16_t buffer [128];
  thresholdContext ctx;
  ctx.averageReading = 0;
  ctx.runningAverage = 0;
  ctx.averagedOver   = 2;
  
  // Infinite loop, ends when script is cancelled
  // Repeatedly, take a sample every 2 microseconds;
  // find the average of 128 samples; and
  // print a running graph of asteriskss as averages
  while (shouldRun) 
    {
      int len = sensor->getSampledWindow (2, 128, buffer);
      if (len) {
        int thresh = sensor->findThreshold (&ctx, 30, buffer, len);
        sensor->printGraph(&ctx, 5);
        if (thresh) {
          // do something ....
        }
      }
    }
  
  cout << "Exiting" << endl;
  
  delete sensor;
  
  return 0;
}

Public Member Functions
	MQ7 (int gasPin)

	~MQ7 ()

std::string	name ()

Public Member Functions inherited from Gas
	Gas (int gasPin)

virtual	~Gas ()

virtual int	getSampledWindow (unsigned int freqMS, int numberOfSamples, uint16_t *buffer)

virtual int	findThreshold (thresholdContext ctx, unsigned int threshold, uint16_t buffer, int len)

virtual int	getSampledData (thresholdContext *ctx)

virtual int	getSample ()

virtual void	printGraph (thresholdContext *ctx, uint8_t resolution)