API for the MQ3 Gas Sensor. More...

Detailed Description

ID: mq3
Name: Grove MQ3 Gas Sensor
Category: gaseous
Manufacturer: seeed
Connection: analog

The Grove MQ3 Gas Sensor module is useful for gas leakage detection (in home and industry). It can detect alcohol vapors and benzine. It's highly sensitive but has a long warm-up time of about 1 minute. It's detection range is 0.04-4 mg/L Alcohol.

int
main(int argc, char **argv)
{
    // Attach gas sensor to A0
    sensor = new upm::MQ3(0);
    signal(SIGINT, sig_handler);
    thresholdContext ctx;
    ctx.averageReading = 0;
    ctx.runningAverage = 0;
    ctx.averagedOver   = 2;
    // Infinite loop, ends when script is cancelled
    // Repeatedly, take a sample every 2 milliseconds;
    // find the average of 128 samples; and
    // print a running graph of the averages using a resolution of 5
    while (!is_running) {
        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 ....
            }
        }
    }
    std::cout << "exiting application" << std::endl;
    delete sensor;
    return 0;
}

Public Member Functions
	MQ3 (int gasPin)

	~MQ3 ()

std::string	name ()

Public Member Functions inherited from Gas
	Gas (int gasPin)

	~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)