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Outcome

Intention

To build a humidifier that can make people’s life easier by adopting remote control and connection with phone. User can customize the machine’s operation with smartphone.

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Context

In this assignment, I want to build a smart humidifier with sensor that can detect the humidity of the room and turn on and off automatically to keep the humidity level consistent. With sending message to the phone, the device can notify you if the water level is low in the machine so you can refill the water in time.

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Components

Particle Photon

LCD light

Humidity/temperature sensor module

Switch

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Process

The goal of this device is to detect the humidity level and using light to notify users when the level reach a certain number. When the level reach 30, the LED will light up; When it is lower than 30, the light will turn off.

First step:

I connected the photon with a DHT22 humidity sensor.

Second step:

Inserted a switch so I can turn on and off the sensor.

Third step:

Installed the LED light and input the code so it will react to the number produced by the sensor.

The challenge I have found was to make the LED light works. I have to change the code and input some of the serious to make the light turn on and off when the number goes up and down.

Billing of parts:

Photon: $19.00

Humidity Sensor: $9.95

LED: $0.5

BreadBoard: $5.00

Jumper Wire: $1.95

Power Switch: $1.50

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#include "HttpClient/HttpClient.h"

// This #include statement was automatically added by the Particle IDE.
#include "Adafruit_DHT/Adafruit_DHT.h"

// Example testing sketch for various DHT humidity/temperature sensors
// Written by ladyada, public domain

#define DHTPIN D2     // what pin we're connected to


// Uncomment whatever type you're using!
//#define DHTTYPE DHT11		// DHT 11
#define DHTTYPE DHT22		// DHT 22 (AM2302)
//#define DHTTYPE DHT21		// DHT 21 (AM2301)

// Connect pin 1 (on the left) of the sensor to +5V
// Connect pin 2 of the sensor to whatever your DHTPIN is
// Connect pin 4 (on the right) of the sensor to GROUND
// Connect a 10K resistor from pin 2 (data) to pin 1 (power) of the sensor

DHT dht(DHTPIN, DHTTYPE);



/**
* Declaring the variables.
*/
unsigned int nextTime = 0;    // Next time to contact the server
HttpClient http;

// Headers currently need to be set at init, useful for API keys etc.
http_header_t headers[] = {
    //  { "Content-Type", "application/json" },
    //  { "Accept" , "application/json" },
    { "Accept" , "*/*"},
    { NULL, NULL } // NOTE: Always terminate headers will NULL
};

http_request_t request;
http_response_t response;

int LedIn = D0;

void setup() {
	Serial.begin(9600);
	Particle.publish("DEBUG","DHT22 test!");
  pinMode(LedIn, OUTPUT);

	dht.begin();
}

void loop() {
// Wait a few seconds between measurements.

	delay(1000);

// Reading temperature or humidity takes about 250 milliseconds!
// Sensor readings may also be up to 2 seconds 'old' (its a
// very slow sensor)
	float h = dht.getHumidity();
// Read temperature as Celsius
	float t = dht.getTempCelcius();
// Read temperature as Farenheit
	float f = dht.getTempFarenheit();


  	Serial.println("\nHumid:");
  	Serial.print(h);
    /*Serial.println("\nTemC: ");
    Serial.print(t);
    Serial.println("\nTemF: ");
    Serial.print(f);*/

// Check if any reads failed and exit early (to try again).
	if (isnan(h) || isnan(t) || isnan(f)) {
		Particle.publish("DEBUG","Failed to read from DHT sensor!");
		return;
	}

  if (h > 30) {
      digitalWrite(LedIn, HIGH);
  }
  if ( h < 30){
      digitalWrite(LedIn, LOW);
  }
// Compute heat index
// Must send in temp in Fahrenheit!
	float hi = dht.getHeatIndex();
	float dp = dht.getDewPoint();
	float k = dht.getTempKelvin();

	//Serial.print("Humid: ");
	//Serial.print(h);
	//Serial.print("% - ");
	//Serial.print("Temp: ");
	//Serial.print(t);
	//Serial.print("*C ");
	//Serial.print(f);
	//Serial.print("*F ");
	//Serial.print(k);
	//Serial.print("*K - ");
	//Serial.print("DewP: ");
	//Serial.print(dp);
	//Serial.print("*C - ");
	//Serial.print("HeatI: ");
	//Serial.print(hi);
	//Serial.println("*C");
	//Serial.println(Time.timeStr());

	//cast floats to string
	String sf(f, 2);
	String sh(h, 2);

	//pblish tests
	//Spark.publish("faranheight",f,60,PRIVATE);
	Particle.publish("TEMP",sf);
	Particle.publish("HUMIDITY",sh);

	//post to dweet
	request.hostname = "dweet.io";
    request.port = 80;
    request.path = "/dweet/for/particlehumiditysesor?temp=" + sf + "&humidity=" + sh;

	//json body doesn't work
	//request.body = "{\"humidity\":\"43%\",\"temp\":\"45f\"}"; //"{\"key\":\"value\"}";

	Particle.publish("DEBUG",request.body);

    // Get request
    http.get(request, response, headers);
    //Spark.publish("DEBUG","Application Response status: ");
    //Particle.publish("DEBUG",response.status);

    //Spark.publish("DEBUG","Application HTTP Response Body: ");
    Particle.publish("DEBUG",response.body);
}

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Reflection

From this assignment, I have learned how the code can be used to produce varied functions that can help us with our daily life. The most difficult part is that when there is no outcome, it is hard to find out whether it is the problem of the connection or the code.

One thing I would like to spend more time on is the understand what exactly each code means and the logic of the order, since I just copied and pasted the code from the tutorial.

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Outcome

Intention

Context

Components

Process

Attribution

Attribution

Attribution

Reflection