LDT0028 Class Reference

API for LDT0-028 PZT film-based sensors, such as a Grove Piezo Vibration sensor. More...

Detailed Description

• ID: ldt0028
• Name: LDT0-028 Piezo Vibration Sensor
• Other Names: Grove Piezo Vibration Sensor
• Category: flexfor
• Manufacturer: seeed
• Connection: analog

This module defines the LDT0-028 interface for libupm-ldt0028

    const int NUMBER_OF_SECONDS = 10;
    const int MICROSECONDS_PER_SECOND = 1000000;
    const int SAMPLES_PER_SECOND = 50;
    const int THRESHOLD = 100;

    // Create the LDT0-028 Piezo Vibration Sensor object using AIO pin 0
    upm::LDT0028* sensor = new upm::LDT0028(0);

    // Read the signal every 20 milliseconds for 10 seconds
    std::cout << "For the next " << NUMBER_OF_SECONDS << " seconds, " 
              << SAMPLES_PER_SECOND << " samples will be taken every second." 
              << std::endl << std::endl;
    uint16_t* buffer = new uint16_t[NUMBER_OF_SECONDS * SAMPLES_PER_SECOND];
    for (int i=0; i < NUMBER_OF_SECONDS * SAMPLES_PER_SECOND; i++) {
        buffer[i] = (uint16_t) sensor->getSample();
        usleep(MICROSECONDS_PER_SECOND / SAMPLES_PER_SECOND);
    }

    // Print the number of times the reading was greater than the threshold
    int count = 0;
    for (int i=0; i < NUMBER_OF_SECONDS * SAMPLES_PER_SECOND; i++) {
        if (buffer[i] > THRESHOLD) {
            count++;
        }
    }
    std::cout << sensor->name() << " exceeded the threshold value of " <<
        THRESHOLD << " a total of " << count << " times," << std::endl
        << "out of a total of " << NUMBER_OF_SECONDS*SAMPLES_PER_SECOND 
        << " readings." << std::endl << std::endl;

    // Print a graphical representation of the average value sampled
    // each second for the past 10 seconds, using a scale factor of 15
    std::cout << "Now printing a graphical representation of the average reading "
        << std::endl << "each second for the last " 
        << NUMBER_OF_SECONDS << " seconds." << std::endl;
    const int SCALE_FACTOR = 15;
    for (int i=0; i < NUMBER_OF_SECONDS; i++) {
        long sum = 0;
        for (int j=0; j < SAMPLES_PER_SECOND; j++) {
            sum += buffer[i*SAMPLES_PER_SECOND + j];
        }
        double average = (double) sum / (double) SAMPLES_PER_SECOND;
        int stars_to_print = (int) round(average / SCALE_FACTOR);
        std::cout << "(" << std::setw(4) << (int) round(average) << ") | ";
        for (int j=0; j<stars_to_print; j++) {
            std::cout << "*";
        }
        std::cout << std::endl;
    }

    // Delete the sensor object
    delete sensor;

Public Member Functions
	LDT0028 (unsigned int pin)
	~LDT0028 ()
std::string	name ()
int	getSample ()

Protected Attributes
std::string	m_name
	name of this sensor
mraa_aio_context	m_pin
	AIO pin.

Constructor & Destructor Documentation

LDT0028

(

unsigned int

pin

)

LDT0028 constructor

Parameters

pin	AIO pin where the sensor is connected

~LDT0028

(

)

LDT0028 destructor

Member Function Documentation

std::string name

(

)

Returns the name of this sensor

Returns

Name of this sensor

int getSample

(

)

Returns one sample from this sensor

Returns

One value from this sensor

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The documentation for this class was generated from the following files:

• /iotdk/jenkins/workspace/upm-doc-stable/src/ldt0028/ldt0028.h
• /iotdk/jenkins/workspace/upm-doc-stable/src/ldt0028/ldt0028.cxx