Dev JhaJames WarrenCarlos Rodriguez
Published

Weather Monitoring System

A weather monitor system that uses sensors to show the temperature, humidity, and air quality.

IntermediateFull instructions provided81
Weather Monitoring System

Things used in this project

Hardware components

Argon
Particle Argon
×1
DHT11 Temperature & Humidity Sensor (3 pins)
DHT11 Temperature & Humidity Sensor (3 pins)
×1
Grove - Gas Sensor(MQ2)
Seeed Grove - Gas Sensor(MQ2)
×1
Grove - Air quality sensor v1.3
Seeed Grove - Air quality sensor v1.3
×1
LDR, 5 Mohm
LDR, 5 Mohm
×1
Resistor 1k ohm
Resistor 1k ohm
×1

Software apps and online services

ThingSpeak API
ThingSpeak API
Particle Build Web IDE
Particle Build Web IDE

Story

Read more

Schematics

Circuit Schematic

Code

Argon Weather Monitor Code

Arduino
#include "Adafruit_DHT.h"

#define DHTPIN 2     // what pin we're connected to

#define DHTTYPE DHT11		// DHT 11 



DHT dht(DHTPIN, DHTTYPE);

SYSTEM_MODE(AUTOMATIC);

void setup() {
    pinMode(A0,INPUT); //LDR PIN
    pinMode(A1,INPUT); //MQ2 PIN
    pinMode(A2,INPUT); //MQ135 PIN
	Serial.begin(115200); 
	dht.begin();
}

void loop() {
    
    // Wait a few seconds between measurements.
    delay(2000);
    // very slow sensor)
	float h = dht.getHumidity();
    // Read temperature as Celsius
	float t = dht.getTempCelcius();
	
	//Get Light Level
	float LDR=analogRead(A0);
	//Read MQ2 Level
	float MQ2=analogRead(A1);
	//Read MQ135 Level
	float MQ135=analogRead(A2);
  
    // Check if any reads failed and exit early (to try again).
	// if (isnan(h) || isnan(t) || isnan(f)) {
	if (isnan(h)) {
		Serial.println("Failed to read from DHT sensor!");
		h=t=0;
	}
	
	//Convert the Sensor Data into JSON Response For  Webhooks which will send the data to ThingSpeak & Zapier for further process
	
	String Data="{\"field1\":\""+String(t)+"\","; //Temp
	Data+="\"field2\":\""+String(h)+"\","; //Humdity
	Data+="\"field3\":\""+String(LDR)+"\","; //LDR
	Data+="\"field4\":\""+String(MQ135)+"\","; //MQ135
	Data+="\"field5\":\""+String(MQ2)+"\"}"; //MQ2
	

	Particle.publish("WeatherData", Data, PUBLIC);
	
	Serial.print("Humid: "); 
	Serial.print(h);
	Serial.print("% - ");
	Serial.print("Temp: "); 
	Serial.print(t);
	Serial.println("*C");
	Serial.print("LDR: ");
	Serial.println(LDR);
	Serial.print("MQ2: ");
	Serial.println(MQ2);
	Serial.print("MQ135: ");
	Serial.println(MQ135);
	Serial.println(Time.timeStr());
	// Wait a few 30 seconds between measurements.
	delay(300000);
}

Argon Weather Monitor SubCode 1

Arduino
#include "Adafruit_DHT.h"

DHT::DHT(uint8_t pin, uint8_t type, uint8_t count) {
	_pin = pin;
	_type = type;
	_count = count;
	firstreading = true;
}

void DHT::begin(void) {
// set up the pins!
	pinMode(_pin, INPUT);
	pinSetFast(_pin);
	_lastreadtime = 0;
}

float DHT::readTemperature() {
	float f;

	if (read()) {
		switch (_type) {
			case DHT11:
				f = data[2];
				return f;
			case DHT22:
			case DHT21:
				f = data[2] & 0x7F;
				f *= 256;
				f += data[3];
				f /= 10;
				if (data[2] & 0x80)
					f *= -1;
				return f;
		}
	}
	return NAN;
}

float DHT::getHumidity() {
	return readHumidity();
}

float DHT::getTempCelcius() {
	return readTemperature();
}

float DHT::getTempFarenheit() {
	return convertCtoF(readTemperature());
}

float DHT::getTempKelvin() {
	return convertCtoK(readTemperature());
}

float DHT::getHeatIndex() {
	return convertFtoC(computeHeatIndex(convertCtoF(readTemperature()), readHumidity()));
}

float DHT::getDewPoint() {
	return computeDewPoint(readTemperature(), readHumidity());
}

float DHT::convertFtoC(float f) {
	return (f - 32) * 5 / 9;
}

float DHT::convertCtoF(float c) {
	return c * 9 / 5 + 32;
}

float DHT::convertCtoK(float c) {
	return c + 273.15;
}

float DHT::readHumidity(void) {
	float f;

	if (read()) {
		switch (_type) {
			case DHT11:
				f = data[0];
				return f;
			case DHT22:
			case DHT21:
				f = data[0];
				f *= 256;
				f += data[1];
				f /= 10;
				return f;
		}
	}
	return NAN;
}

float DHT::computeHeatIndex(float tempFahrenheit, float percentHumidity) {

	return -42.379 + 
		 2.04901523 * tempFahrenheit + 
		10.14333127 * percentHumidity +
		-0.22475541 * tempFahrenheit * percentHumidity +
		-0.00683783 * pow(tempFahrenheit, 2) +
		-0.05481717 * pow(percentHumidity, 2) + 
		 0.00122874 * pow(tempFahrenheit, 2) * percentHumidity + 
		 0.00085282 * tempFahrenheit * pow(percentHumidity, 2) +
		-0.00000199 * pow(tempFahrenheit, 2) * pow(percentHumidity, 2);
}

float DHT::computeDewPoint(float tempCelcius, float percentHumidity) {
	double a = 17.271;
	double b = 237.7;
	double tC = (a * (float) tempCelcius) / (b + (float) tempCelcius) + log( (float) percentHumidity / 100);
	double Td = (b * tC) / (a - tC);
	return Td;
}

boolean DHT::read(void) {
	uint8_t laststate = HIGH;
	uint8_t counter = 0;
	uint8_t j = 0, i;
	unsigned long currenttime;

// Check if sensor was read less than two seconds ago and return early
// to use last reading.
	currenttime = millis();
	if (currenttime < _lastreadtime) {
// ie there was a rollover
		_lastreadtime = 0;
	}
	if (!firstreading && ((currenttime - _lastreadtime) < 2000)) {
		return true; // return last correct measurement
//		delay(2000 - (currenttime - _lastreadtime));
	}
	firstreading = false;
/*
	Serial.print("Currtime: "); Serial.print(currenttime);
	Serial.print(" Lasttime: "); Serial.print(_lastreadtime);
*/
	_lastreadtime = millis();

	data[0] = data[1] = data[2] = data[3] = data[4] = 0;
  
// pull the pin high and wait 250 milliseconds
	pinSetFast(_pin);
	delay(250);

// now pull it low for ~20 milliseconds
	pinMode(_pin, OUTPUT);
	pinResetFast(_pin);
	delay(20);
	noInterrupts();
	pinSetFast(_pin);
	delayMicroseconds(40);
	pinMode(_pin, INPUT);

// read in timings
	for ( i=0; i< MAXTIMINGS; i++) {
		counter = 0;
		while (pinReadFast(_pin) == laststate) {
			counter++;
			delayMicroseconds(1);
			if (counter == 255) {
				break;
			}
		}
		laststate = pinReadFast(_pin);

		if (counter == 255) break;

// ignore first 3 transitions
		if ((i >= 4) && (i%2 == 0)) {
// shove each bit into the storage bytes
			data[j/8] <<= 1;
			if (counter > _count)
				data[j/8] |= 1;
			j++;
		}
	}

	interrupts();

/*
	Serial.println(j, DEC);
	Serial.print(data[0], HEX); Serial.print(", ");
	Serial.print(data[1], HEX); Serial.print(", ");
	Serial.print(data[2], HEX); Serial.print(", ");
	Serial.print(data[3], HEX); Serial.print(", ");
	Serial.print(data[4], HEX); Serial.print(" =? ");
	Serial.println(data[0] + data[1] + data[2] + data[3], HEX);
*/

// check we read 40 bits and that the checksum matches
	if ((j >= 40) && 
	   (data[4] == ((data[0] + data[1] + data[2] + data[3]) & 0xFF)) ) {
		return true;
	}
 
	return false;

}	

Argon Weather Monitor SubCode 2

Arduino
#ifndef DHT_H
#define DHT_H

#include "application.h"
#include "math.h"

// how many timing transitions we need to keep track of. 2 * number bits + extra
#define MAXTIMINGS 85

#define DHT11 11
#define DHT22 22
#define DHT21 21
#define AM2301 21

class DHT {
	private:
		uint8_t data[6];
		uint8_t _pin, _type, _count;
		unsigned long _lastreadtime;
		boolean firstreading;
		float readTemperature();
		float convertFtoC(float);
		float convertCtoF(float);
		float convertCtoK(float);
		float computeHeatIndex(float tempFahrenheit, float percentHumidity);
		float computeDewPoint(float tempCelcius, float percentHumidity);
		float readHumidity(void);
		boolean read(void);

	public:
		DHT(uint8_t pin, uint8_t type, uint8_t count=6);
		void begin(void);
		float getHumidity();
		float getTempCelcius();
		float getTempFarenheit();
		float getTempKelvin();
		float getHeatIndex();
                float getDewPoint();

};
#endif

Credits

Dev Jha

Dev Jha

1 project • 0 followers
James Warren

James Warren

1 project • 0 followers
Carlos Rodriguez

Carlos Rodriguez

1 project • 0 followers

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