This blog will discuss the integration of the required materials stated in Blog #2 and Blog #3. Below are the steps for integrating all the materials to develop our Seeeduino SAMD21-based Indoor Caron Dioxide Monitoring Device.
- Prepare the required materials discussed in Blog #2.
- Connect your sensors to the SAMD21 Microcontroller pins. Kindly follow the wiring diagram below.
- Connect your Seeeduino XIAO SAMD21 Microcontroller to your PC or Laptop via a USB Type-C Cable.
- Create a new Arduino Sketch and paste the following program below.
#include "Wire.h"
#include <MQ135.h>
#include <DHT.h>
#include <RGBLed.h>
#include <LiquidCrystal_I2C.h>
#define PIN_MQ135 A1
#define DHTTYPE DHT20
#define BUZZER 3
#define REDLED 10
#define GREENLED 9
#define BLUELED 8
LiquidCrystal_I2C lcd(0x27, 20, 4);
MQ135 mq135_sensor(PIN_MQ135);
DHT dht(DHTTYPE);
RGBLed led(REDLED, GREENLED, BLUELED, RGBLed::COMMON_ANODE);
unsigned long readMillis;
unsigned long currentMillis;
const unsigned long readPeriod = 2000;
int redcolor = 0;
int greencolor = 0;
int bluecolor = 0;
void setup() {
analogReadResolution(12);
Serial.begin(115200);
lcd.init();
Wire.begin();
dht.begin();
lcd.backlight();
lcd.setCursor(1, 0);
lcd.print("Indoor Air Quality");
lcd.setCursor(1, 1);
lcd.print("Monitoring Device");
lcd.setCursor(0, 2);
lcd.print("System Initializing");
lcd.setCursor(0, 3);
for (int i = 0; i < 20; i++)
{
lcd.print(".");
delay(100);
}
lcd.setCursor(0, 3);
for (int i = 0; i < 20; i++)
{
lcd.print(" ");
delay(100);
}
lcd.setCursor(8, 3);
lcd.print("DONE");
delay(100);
//lcd.setCursor(0, 0);
//lcd.print("Real-time Air Status");
readMillis = millis();
}
void loop() {
currentMillis = millis();
if (currentMillis - readMillis >= readPeriod) {
float temp_hum_val[2] = {0};
if (!dht.readTempAndHumidity(temp_hum_val)) {
// do nothing
}
float rzero = mq135_sensor.getRZero();
float correctedRZero = mq135_sensor.getCorrectedRZero(temp_hum_val[1], temp_hum_val[0]);
float resistance = mq135_sensor.getResistance();
float ppm = mq135_sensor.getPPM();
float correctedPPM = mq135_sensor.getCorrectedPPM(temp_hum_val[1], temp_hum_val[0]);
/*
Serial.print("MQ135 RZero: ");
Serial.print(rzero);
Serial.print("\t Corrected RZero: ");
Serial.print(correctedRZero);
Serial.print("\t Resistance: ");
Serial.print(resistance);
Serial.print("\t PPM: ");
Serial.print(ppm);
Serial.print("\t Corrected PPM: ");
Serial.print(correctedPPM);
Serial.println("ppm");
*/
lcd.clear();
//delay(100);
lcd.setCursor(3, 1);
lcd.print("PPM: ");
lcd.print(correctedPPM);
lcd.print(" ppm");
lcd.setCursor(0, 2);
lcd.print("Temperature: ");
lcd.print(temp_hum_val[1]);
lcd.print(" C");
lcd.setCursor(2, 3);
lcd.print("Humidity: ");
lcd.print(temp_hum_val[0]);
lcd.print("%");
float pm_sensor_reading = correctedPPM;
if (pm_sensor_reading >= 0.0 && pm_sensor_reading <= 50.0) {
lcd.setCursor(7, 0);
lcd.print("Good");
//aqi_cat[] = s"Good";
redcolor = 0;
greencolor = 228;
bluecolor = 0;
led.setColor(redcolor, greencolor, bluecolor); //green
digitalWrite(BUZZER, LOW);
Serial.println(F("Good"));
}
else if (pm_sensor_reading >= 51.0 && pm_sensor_reading <= 100.0) {
lcd.setCursor(6, 0);
lcd.print("Moderate");
//aqi_cat = "Moderate";
redcolor = 255;
greencolor = 255;
bluecolor = 0;
led.setColor(redcolor, greencolor, bluecolor); //yellow
digitalWrite(BUZZER, LOW);
Serial.println(F("Moderate"));
}
else if (pm_sensor_reading >= 101.0 && pm_sensor_reading <= 150.0) {
lcd.setCursor(3, 0);
lcd.print("Unhealthy for");
lcd.setCursor(2, 1);
lcd.print("Sensitive Groups");
//aqi_cat = "Unhealthy for Sensitive Groups";
redcolor = 255;
greencolor = 126;
bluecolor = 0;
led.setColor(redcolor, greencolor, bluecolor); //orange
digitalWrite(BUZZER, LOW);
Serial.println(F("Unhealthy for Sensitive Group"));
}
else if (pm_sensor_reading >= 251.0 && pm_sensor_reading <= 200.0) {
lcd.setCursor(5, 0);
lcd.print("Unhealthy");
//aqi_cat = "Unhealthy";
redcolor = 255;
greencolor = 0;
bluecolor = 0;
led.setColor(redcolor, greencolor, bluecolor); //red
digitalWrite(BUZZER, HIGH);
Serial.println(F("Unhealthy"));
}
else if (pm_sensor_reading >= 201.0 && pm_sensor_reading <= 300.0) {
lcd.setCursor(3, 0);
lcd.print("Very Unhealthy");
//aqi_cat = "Very Unhealthy";
redcolor = 143;
greencolor = 63;
bluecolor = 151;
led.setColor(redcolor, greencolor, bluecolor); //purple
digitalWrite(BUZZER, HIGH);
Serial.println(F("Very Unhealthy"));
}
else if (pm_sensor_reading >= 301.0 && pm_sensor_reading <= 500.0) {
lcd.setCursor(5, 0);
lcd.print("Hazardous");
//aqi_cat = "Hazardous";
redcolor = 126;
greencolor = 0;
bluecolor = 35;
led.setColor(redcolor, greencolor, bluecolor); //maroon
digitalWrite(BUZZER, HIGH);
Serial.println(F("Hazardous"));
}
else if (pm_sensor_reading >= 501.0) {
lcd.setCursor(5, 0);
lcd.print("Hazardous");
//aqi_cat = "Hazardous";
redcolor = 126;
greencolor = 0;
bluecolor = 35;
led.setColor(redcolor, greencolor, bluecolor); //maroon
digitalWrite(BUZZER, HIGH);
Serial.println(F("Hazardous"));
}
else {
redcolor = 0;
greencolor = 0;
bluecolor = 0;
led.setColor(redcolor, greencolor, bluecolor);
digitalWrite(BUZZER, LOW);
lcd.setCursor(8, 0);
lcd.print("None");
//aqi_cat = "None";
}
readMillis = millis();
}
}
- Save the Arduino sketch.
- Upload the demo. If you do not know how to upload the code, please check how to upload the code.
- Open the Serial Monitor of Arduino IDE by clicking Tool-> Serial Monitor. Or tap the CTRL+SHIFT+M keyboard keys at the same time. if everything goes well, you will get the readings.
Top Comments