Controlling air conditioner temperature through Android phone
Working of the project
What is NodeMCU and how does it work
Setting up the Adafruit dashboard
Schematics
Diagram

Published July 11, 2019 © GPL3+

Controlling Air Conditioner temperature Through Internet

Learn how to make you air conditioner smart by allowing it to be controlled by your phone from anywhere in the world!

BeginnerFull instructions provided2 hours6,716

Controlling Air Conditioner temperature Through Internet

Things used in this project

Hardware components

NodeMCU ESP8266 Breakout Board

DHT11 Temperature & Humidity Sensor (4 pins)

Digilent 5V 2.5A Switching Power Supply

Adafruit Standard LCD - 16x2 White on Blue

I2c module

Single channel relay

Software apps and online services

Arduino IDE

Hand tools and fabrication machines

Hot glue gun (generic)

10 Pc. Jumper Wire Kit, 5 cm Long

Solder Wire, Lead Free

Story

Controlling air conditioner temperature through Android phone

In this project, we can monitor the current temperature of the air conditioner and control the temperature by moving the slider in Adafruit. The dashboard user interface is very simple and precise, everyone can use it seamlessly.

Working of the project

We can assign our desired temperature by moving the slider. Once the temp is set, the Arduino code compares the AC temp with current room temperature. In this project, a DHT11 is used to measure room temperature.

Suppose if we set the temperature to 24 degrees Celcius and the room temperature is 26 degrees. As the assigned temperature is less than the current temperature of the room, the AC will be running till it reaches the assigned temperature.

You can watch the working video.

I also have added an LCD display so that we can understand the condition of the air conditioner, whether it is on or off. It also shows the assigned temperature and current temperature of the room.

What is NodeMCU and how does it work?

We can say NodeMCU is a combination of Arduino Nano and ESP8266 WiFi module. It becomes a power module because of this combination, with this thing we can do all the projects related to Arduino and ESP8266.

In this project, we used a DHT11 to sense temperature. It sends the temperature value to Adafruit server and displays the value in the gauge. There is also a slider to control the temperature, the assigned temperature will also show in the gauge.

Setting up the Adafruit dashboard

Step 1: Create a account in adafruit.io

Step 2: Sign in to the account

Step 3: Create a dashboard

Give the dashboard name as AC. you can choose your desired name, but you need to change the name in the code as well.

Ac dashboard for assigning temperature and showing assigned temperature

Create another dashboard named "temp" for showing the room temperature. Follow the previous step to create dashboard.

Step 4: Add gauges and slider into the dashboard

Click on the + button to add gauges and slider.

Add gauge for showing assigned temperature.

Click on the gauge

When we click on the gauge it will ask for selecting the feed, select the AC feed.

After that, give the feed a name, set gauge minimum and maximum values, and update the block.

Create a slider for controlling the temperature.

When we click on the slider it will ask for selecting the feed, select the AC feed.

After that give the feed a name, set slider minimum and maximum values, and update the block.

NB: You can set the slider incremental value according as you wish. I'll set it as 1 degree.

Add a gauge for showing the air conditioner temperature, but in this case choose the feed as temp.

Click on the plus button.

Click on the gauge button.

Chosse the feed as temp.

Give the gauge a name and set the gauge maximum and minimum value.

Now the Adafruit dashboard setup is complete..

Step 5: Upload the code to NodeMCU

Before uploading the code, we need to add our WiFi name and password into the code, as well the Adafruit username and AIO key.

Adafruit username and AIO key can be obtained from the dashboard.

For that click on the key button in the dashboard.

And in the next window it shows the username and AIO key.

Copy this username, AIO key and add it into your code.

Step 6: Upload the code into NodeMCU by selecting the port, board name, etc.

How to program nodemcu

Schematics

For making the LCD connection easier iI used i2c module, you can learn how to connect I2C module to LCD display by watching this video:

Diagram

Connect SCL pin to D1

SDA to D2

DHT11 data pin to D3

Relay data in pin to D5

Connect the vcc, gnd of NodeMCU, relay, LCD display, DHT11 to power supply.

Wow, the project is complete! You can watch the working of the project down below.

For making this project a success, I will give you some tips:

Split this project into parts.
First of all, try to monitor the sensor data into Adafruit.
After that, check whether the slider is working.
Then set up the LCD display. The library may vary according to which LCD display used. Actually, the LCD display is not required. The choice is yours!
If you have any doubts regarding this project, you can ask me in the comment section. I am always here to help.

Send me your valuable feedback to this project!

Have a great day, hacksters!

Insanescience

Code

Air conditioner

#include <LiquidCrystal_I2C.h>//link to liquid crytal library file:///C:/Users/ajith/Downloads/LiquidCrystal_I2C-master%20(2).zip
#include <ESP8266WiFi.h>

#include <DHT.h>//link to dht 11 library https://www.electronicwings.com/download/attachment=Fri-08-17-20-48-58.NodeMCU_DHT11.zip
#define DHT11_PIN 2
DHT DHT(DHT11_PIN,DHT11);


   //pin where the dht11 is connected

#include <Wire.h>
LiquidCrystal_I2C lcd(0x3F, 16, 2);

#include "Adafruit_MQTT.h"
#include "Adafruit_MQTT_Client.h"
#define relay D5
#define DHT11_PIN 0
/************************* WiFi Access Point *********************************/

#define WLAN_SSID       "Your wifi ssid"
#define WLAN_PASS       "Your wifi password"

/************************* Adafruit.io Setup *********************************/

#define AIO_SERVER      "io.adafruit.com"
#define AIO_SERVERPORT  1883                   // use 8883 for SSL
#define AIO_USERNAME    "adafruit username"
#define AIO_KEY         "aio key"

/************ Global State (you don't need to change this!) ******************/

// Create an ESP8266 WiFiClient class to connect to the MQTT server.
WiFiClient client;
// or... use WiFiFlientSecure for SSL
//WiFiClientSecure client;

// Setup the MQTT client class by passing in the WiFi client and MQTT server and login details.
Adafruit_MQTT_Client mqtt(&client, AIO_SERVER, AIO_SERVERPORT, AIO_USERNAME, AIO_KEY);

const char SLIDER_FEED[] PROGMEM = AIO_USERNAME "/feeds/temp";
Adafruit_MQTT_Subscribe temp = Adafruit_MQTT_Subscribe(&mqtt, AIO_USERNAME "/feeds/Temperature_control");
/****************************** Feeds ***************************************/

// Setup a feed called 'photocell' for publishing.
// Notice MQTT paths for AIO follow the form: <username>/feeds/<feedname>


// Setup a feed called 'onoff' for subscribing to changes.
Adafruit_MQTT_Subscribe onoffbutton = Adafruit_MQTT_Subscribe(&mqtt, AIO_USERNAME "/feeds/Ac");

Adafruit_MQTT_Publish ac = Adafruit_MQTT_Publish(&mqtt, AIO_USERNAME "/feeds/temp");
/*************************** Sketch Code ************************************/

// Bug workaround for Arduino 1.6.6, it seems to need a function declaration
// for some reason (only affects ESP8266, likely an arduino-builder bug).

void MQTT_connect();

void setup() {
  pinMode(relay, OUTPUT);
  Serial.begin(115200);
  delay(10);


  Serial.println(F("Adafruit MQTT demo"));

  // Connect to WiFi access point.
  Serial.println(); Serial.println();
  Serial.print("Connecting to ");
  Serial.println(WLAN_SSID);

Wire.begin(D2, D1);
lcd.home();
 lcd.setCursor(0, 0);
  lcd.print("Scanning wifi");
  delay(2000);
  lcd.clear();
  lcd.print("Connecting to ");
  delay(2000);
   lcd.setCursor(0, 1);
 lcd.print(WLAN_SSID);
  WiFi.begin(WLAN_SSID, WLAN_PASS);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println();

  Serial.println("WiFi connected");
  delay(2000);
  lcd.clear();
  lcd.print("WiFi connected");
  Serial.println("IP address: "); Serial.println(WiFi.localIP());
  ////////////////////////
 
   lcd.setCursor(0, 1);
  lcd.print("IP:");
   lcd.setCursor(3, 1);
     lcd.print(WiFi.localIP());
delay(3000);

  mqtt.subscribe(&onoffbutton);

  mqtt.subscribe(&temp);

}

uint32_t x = 0;

void loop() {
  // Ensure the connection to the MQTT server is alive (this will make the first
  // connection and automatically reconnect when disconnected).  See the MQTT_connect
  // function definition further below.
  MQTT_connect();
  ////////////////////////////////////


  Serial.print(F("\nSending myValue "));
  ///////////////////////////////


 float t = DHT.readTemperature();
  ///////////////////////////////
  Serial.print("...");
  if (! ac.publish(t)) {
    Serial.println(F("Failed"));
  } else {
    Serial.println(F("OK!"));
     Serial.println(t);
  }
  float state = atoi((char *)onoffbutton.lastread);
 lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("C Temp=");
  lcd.setCursor(7, 0);
  lcd.print(t);
  lcd.setCursor(12, 0);
  lcd.print((char)223);
  lcd.setCursor(13, 0);
  lcd.print("c");
  lcd.setCursor(0, 1);
  lcd.println("R Temp=");
  lcd.setCursor(7, 1);
  lcd.print(state);
  lcd.setCursor(12, 1);
  lcd.print((char)223);
  lcd.setCursor(13, 1);
  lcd.print("c");
  Serial.println(state);

  //////////////////////////////////
  // this is our 'wait for incoming subscription packets' busy subloop
  // try to spend your time here

  Adafruit_MQTT_Subscribe *subscription;
  while ((subscription = mqtt.readSubscription(5000))) {
    uint16_t state = atoi((char *)onoffbutton.lastread);

  float t = DHT.readTemperature();
    if (state < t) {
      Serial.print(F("Relay state: "));
      Serial.println((char *)onoffbutton.lastread);


      Serial.println(state);
      Serial.println(t);
      digitalWrite(relay, LOW);
      void data();
        delay(3000);
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("PELTIER ON");
    }
    else if (state > t) {
      Serial.print(F("Relay state: "));
      digitalWrite(relay, HIGH);
    Serial.println(t);
     lcd.clear();
    void data();
 lcd.clear();
     
      lcd.setCursor(0, 0);
       lcd.print("PELTIER OFF");}
        
      ////////////////////////////////////


      ///////////////////////////

    
  }
}




void MQTT_connect() {
  int8_t ret;

  // Stop if already connected.
  if (mqtt.connected()) {
    return;
  }

  Serial.print("Connecting to MQTT... ");
  lcd.setCursor(0, 0);
  lcd.clear();
lcd.print("Connecting to MQTT");
  uint8_t retries = 3;
  while ((ret = mqtt.connect()) != 0) { // connect will return 0 for connected
    Serial.println(mqtt.connectErrorString(ret));
    Serial.println("Retrying MQTT connection in 5 seconds...");
    lcd.print("Retrying MQTT");
    mqtt.disconnect();
    delay(5000);  // wait 5 seconds
    retries--;
    if (retries == 0) {
      // basically die and wait for WDT to reset me
      while (1);
    }
  }
  Serial.println("MQTT Connected!");
  lcd.setCursor(0, 1);
  lcd.print("MQTT Connected!");
  lcd.clear();
}
void data()
{
   float t = DHT.readTemperature();
   float state = atoi((char *)onoffbutton.lastread);
    lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("C Temp=");
  lcd.setCursor(7, 0);
  lcd.print(t);
  lcd.setCursor(12, 0);
  lcd.print((char)223);
  lcd.setCursor(13, 0);
  lcd.print("c");
  lcd.setCursor(0, 1);
  lcd.println("R Temp=");
  lcd.setCursor(7, 1);
  lcd.print(state);
  lcd.setCursor(12, 1);
  lcd.print((char)223);
  lcd.setCursor(13, 1);
  lcd.print("c");
  Serial.println(state);
}