•

yardentd

Published July 28, 2021 © MIT

Keep Your Home a Safe Place

An indoor air quality monitoring system with dust and air pollution sensors which operates a fan independently

IntermediateProtip392

Things used in this project

Hardware components

Arduino Oplà IoT Kit

Seeed Studio Grove - Dust Sensor（PPD42NS）

Seeed Studio Grove - Air quality sensor v1.3

Axial Fan, 12 V

Story

Approximately 334 million people worldwide are suffering from asthma. Exposure to air pollution, dust, environmental allergens, and dust mites increases the risk of an asthma attack for those who have asthma. Our goal is to make the air around these people safer by developing a system that can detect dust and alert when air pollution levels are increasing. By installing our system inside asthma patients' homes, we can monitor the air quality in real time and activate the air filtration well in advance.

About the code:

First we need to include thingsProperties.h and Arduino_MKRIoTCarrier.h libraries. We will begin by creating the carrier object by using the MKRIoTCarrier carrier command. Next step we define some variables:Display colors for the led screen, sensors variables and boolean variable.

The void setup() of this program:

The first thing we do is to set the serial communication at a baud rate of 9600, which is a standard rate. We also include the command while(ArduinoCloude); which basically means that unless we connect the device to the cloud nothing will happen. After it, we use the command CARRIER_CASE = false;, which indicates that we are not using the plastic enclosure. Finally we use the commands pinMode in order to define our input channels and then use carrier.begin() to initialize the carrier.

the void loop() of this program:First we will read the temperature and the humidity sensors on the MKR IoT Carrier, Then we would like to print the values in the Serial Monitor.

Every 3s we will take a measurement of the dust sensor and the air quality sensor, this will be done by putting the if statement if ( (millis() - start_time) > sample_time_ms).

Based on the formula provided on the official Grove Sensors website, we can calculate the concentration of dust circulating in the air.

Our next step will be to examine the air quality using if statements:

Very High Pollution → current_quality >= 1000

High Pollution → current_quality >= 700

Low Pollution → current_quality >= 300

Fresh air → current_quality < 300

In order to display air quality and give the user immediate feedback, we will use 5 if else statements. In each statement we will display on the carrier screen the message according to the concentration and the current_quality.

The last part of the code enables the user to turn on and off the fan, using onTouchDown trigger and boolean variable fan_flag

1 / 2

1 / 3

Code

Code

//#include"AirQuality.h"
#include "thingProperties.h"
#include <Arduino_MKRIoTCarrier.h>
MKRIoTCarrier carrier;

//Colors
uint32_t noColor = carrier.leds.Color( 0, 0, 0); // no color
uint32_t colorRed = carrier.leds.Color(0, 255, 0);   //RED
uint32_t colorGreen = carrier.leds.Color(255, 0, 0);  //GREEN
uint32_t colorWhite = carrier.leds.Color( 255, 255, 255); // WHITE
uint32_t colorYellow = carrier.leds.Color( 255, 255, 0); // yellow
uint32_t colorBlue = carrier.leds.Color( 0, 0, 255); // blue
uint32_t colorPurple = carrier.leds.Color( 255, 0, 255); // purple

//int pir_movement = A4;
int pir_movement_state = 0;

int pir_dust = A6;
int air_quality_sensor = A5 ;


unsigned long duration;
unsigned long start_time;
unsigned long sample_time_ms = 3000;//sample 3s ;
unsigned long low_pulse_occupancy = 0;
float ratio = 0;

void setup() {
  // Initialize serial and wait for port to open:
  Serial.begin(9600);
 
  // Defined in thingProperties.h
  initProperties();
 
  // Connect to Arduino IoT Cloud
  ArduinoCloud.begin(ArduinoIoTPreferredConnection);
  //Get Cloud Info/errors , 0 (only errors) up to 4
  setDebugMessageLevel(2);
  ArduinoCloud.printDebugInfo();
 
  //Wait to get cloud connection to init the carrier
  while (ArduinoCloud.connected() != 1) {
    ArduinoCloud.update();
    delay(500);
  }
 
  delay(500);
  CARRIER_CASE = false;
  carrier.begin();
  carrier.display.setRotation(0);
  delay(1000);
  pinMode(A5, INPUT);
  pinMode(A6, INPUT);
  //pinMode(A4, INPUT);
  
  start_time = millis();
}

void loop() {
  ArduinoCloud.update();
  carrier.Buttons.update();

  temperature = carrier.Env.readTemperature();
  humidity = carrier.Env.readHumidity();
  Serial.print("Temperature: ");
  Serial.print(temperature);
  Serial.print(", Humidity: ");
  Serial.println(humidity);
  
  
  duration = pulseIn(pir_dust, LOW);
  low_pulse_occupancy = low_pulse_occupancy + duration;
 
  if ((millis()-start_time) > sample_time_ms)//if the sampel time == 3s
  {
      // operations on the dust sensor
      ratio = low_pulse_occupancy / (sample_time_ms*10.0);  // Integer percentage 0=>100
      concentration = 1.1*pow(ratio,3)-3.8*pow(ratio,2)+520*ratio+0.62; // using spec sheet curve
      Serial.print("concentration = ");
      Serial.print(concentration);
      Serial.println(" pcs/0.01cf  - ");
      low_pulse_occupancy = 0;
      start_time = millis();
      
      // operations on the air-pollution sensor
      current_quality = analogRead(air_quality_sensor);
      if (current_quality >= 1000){
        Serial.println("Very High Pollution!");
      }
      else if (current_quality >= 700){
        Serial.println("High pollution!");
      }
      else if (current_quality >= 300){
        Serial.println("Low pollution!");
      }
      else{
        Serial.println("Fresh air");
      }
      
      if((concentration > 6000) || (current_quality >= 1000)){
        carrier.display.fillScreen(ST77XX_BLACK); //black background
        carrier.display.setTextColor(ST77XX_BLUE); //blue text
        carrier.display.setTextSize(3); //medium sized text
        //sets position for printing (x and y)
        carrier.display.setCursor(45, 70);
        carrier.display.println("HAZARD!");
        carrier.leds.fill(colorBlue, 0, 5);
        carrier.leds.show();
        
      }
      
      else if((concentration > 4500 && concentration < 10000) || (current_quality <= 1000 && current_quality >= 700)){
        carrier.display.fillScreen(ST77XX_BLACK); //black background
        carrier.display.setTextColor(ST77XX_RED); //red text
        carrier.display.setTextSize(3); //medium sized text
        //sets position for printing (x and y)
        carrier.display.setCursor(50, 70);
        carrier.display.println("HEAVY");
        carrier.leds.fill(colorRed, 0, 5);
        carrier.leds.show();
        
      }
      
      else if ((concentration > 3000 && concentration < 8000) || (current_quality <= 700 && current_quality >= 500)){
        carrier.display.fillScreen(ST77XX_BLACK); //black background
        carrier.display.setTextColor(ST77XX_YELLOW); //yellow text
        carrier.display.setTextSize(3); //medium sized text
        //sets position for printing (x and y)
        carrier.display.setCursor(30, 70);
        carrier.display.println("ACCEPTABLE");
        carrier.leds.fill(colorYellow, 0, 5);
        carrier.leds.show();
        
      }
      
      else if ((concentration > 1500 && concentration < 6000) || (current_quality <= 500 && current_quality >= 300)) {
        carrier.display.fillScreen(ST77XX_BLACK); //black background
        carrier.display.setTextColor(ST77XX_GREEN); //green text
        carrier.display.setTextSize(3); //medium sized text
        //sets position for printing (x and y)
        carrier.display.setCursor(55, 70);
        carrier.display.println("GOOD");
        carrier.leds.fill(colorGreen, 0, 5);
        carrier.leds.show();
      }    
      
      else{
        carrier.display.fillScreen(ST77XX_BLACK); //black background
        carrier.display.setTextColor(ST77XX_WHITE); //white text
        carrier.display.setTextSize(3); //medium sized text
        //sets position for printing (x and y)
        carrier.display.setCursor(55, 70);
        carrier.display.println("CLEAN");
        carrier.leds.fill(colorWhite, 0, 5);
        carrier.leds.show();
      }
      
      if(fan_flag){
        if(concentration > 6000 || current_quality >= 500) carrier.Relay1.open();
        else carrier.Relay1.close(); 
      } 
      
  }
  
  // motion check
  //pir_movement_state = digitalRead(pir_movement); 
   
  //if(pir_movement_state == HIGH) { // if motion detected
  //  onMovementEventChange();
  //}
  
  if(carrier.Button0.onTouchDown()) { // button press
	  fan_flag = !fan_flag;
	  carrier.display.fillScreen(ST77XX_BLACK);
    carrier.display.setTextColor(colorPurple);
    carrier.display.setTextSize(2);
	  if(fan_flag){
      carrier.display.print("fan mode is active");
	  }
	  else{
	     carrier.display.print("fan mode is off");
	  }
  }
}

void onMovementEventChange() {
    carrier.leds.fill(colorPurple, 0, 5);
    carrier.leds.show();  
    carrier.display.fillScreen(ST77XX_BLACK); //black background
    carrier.display.setTextColor(colorPurple); //purple text
    carrier.display.setTextSize(2); //medium sized text
    //sets position for printing (x and y)
    carrier.display.setCursor(20, 40);
    carrier.display.print("Temperature: ");
    carrier.display.println(temperature);
    carrier.display.setCursor(20, 60);
    carrier.display.print("Humidity: ");
    carrier.display.println(humidity);
    carrier.display.setCursor(20, 80);
    carrier.display.print("concentration: "); 
    carrier.display.print(concentration);
    carrier.display.println(" pcs/0.01cf");
    carrier.display.setCursor(20, 100);
    carrier.display.print("Air-Pollute measure: "); 
    carrier.display.print(current_quality);
    delay(3000);
}

void onHumidityChange() {
  
}

void onTemperatureChange() {
  // Do something
}

void onConcentrationChange() {
  // Do something
}

void onCurrentQualityChange() {
  // Do something
}

void onFanFlagChange() {
  // Do something
}

Credits

michwa15

1 project • 1 follower

yardentd

1 project • 2 followers

Keep Your Home a Safe Place

Things used in this project

Hardware components

Story

Schematics

Demo

Code

Code

Credits

michwa15

yardentd

Comments

Embed the widget on your own site

Keep Your Home a Safe Place

Keep Your Home a Safe Place

Things used in this project

Hardware components

Story

Schematics

Demo

Code

Code

Credits

michwa15

yardentd

Comments

Related channels and tags