Building a Smart Thermostat Part 2

This is part 2 of the Smart Thermostat project. In part 2 we add the following features to our thermostat design:

• Bluetooth control so the thermostat can be controlled remotely so you can control the temperature of your home from the comfort of your couch or bed
• Mount the project so it is in a much more usable and aesthetically pleasing form then the prototype form it we saw in part 1
• A power save mode to cut down on the utility costs 

In part three we will create the Android app and add a power supply to run it off of the 24 VAC signal coming from the HVAC system. To download the Arduino code follow the GitHub link below. Please share your comments!

Arduino code from GitHub

Smart Thermostat Part 2

Getting Started with the HC-06 Bluetooth Module

In this video we look at how to get started with the HC-06 Bluetooth transceiver module. The HC-06 is a great low cost way to add wireless communication to any project. Since the HC-06 uses a serial line to communicate it is easy to pair it with an Arduino.

Watch Video on Youtube: https://www.youtube.com/watch?v=ZdvKh3c_yoQ

AT Command	REply from HC-06	COMMENTs
AT	OK	Used to verify communication
AT+VERSION	OKlinvorV1.8	The firmware version
AT+NAMEmyBT	OKsetname	Sets the module name to “myBT”
AT+PIN1234	OKsetPIN	Sets the module PIN to 1234
AT+BAUD1	OK1200	Sets the baud rate to 1200
AT+BAUD2	OK2400	Sets the baud rate to 2400
AT+BAUD3	OK4800	Sets the baud rate to 4800
AT+BAUD4	OK9600	Sets the baud rate to 9600
AT+BAUD5	OK19200	Sets the baud rate to 19200
AT+BAUD6	OK38400	Sets the baud rate to 38400
AT+BAUD7	OK57600	Sets the baud rate to 57600
AT+BAUD8	OK115200	Sets the baud rate to 115200
AT+BAUD9	OK230400	Sets the baud rate to 230400
AT+BAUDA	OK460800	Sets the baud rate to 460800
AT+BAUDB	OK921600	Sets the baud rate to 921600
AT+BAUDC	OK1382400	Sets the baud rate to 1382400

Method 1 Setup

/*This sketch Configures the name and baud rate of an HC 06 Bluetooth module */

char message1[10];//need length of chars being read +1 for null character

char message2[9];

void setup() {

  // set baud rate then delay to give user time to open serial monitor

  Serial.begin(9600);

  delay(5000);

  //Send command to set name of HC06 module, with the below command name will change to "forcetronics"

  Serial.print("AT+NAMEForceT");

  delay(600); //HC06 requires 500 msec for reply

  int8_t count = 0; //declare and intialize count 

  while(1) { //loop until OKsetname is read and cleared from buffer

    if(Serial.available()) {

        message1[count] = Serial.read(); //read in char

        count++; 

        if(count == 9) break; //after we get all 9 char break out of loop

    }

    delay(10);

  }

  

  //Send AT command to change baud rate to 115200

  Serial.print("AT+BAUD8");

  delay(600); //HC06 requires 500 msec for reply

  count = 0; //intialize count

  while(1) { //loop until OK115200 is read and cleared from buffer

    if(Serial.available()) {

        message2[count] = Serial.read(); 

        count++; 

        if(count == 8) break; 

    }

    delay(10);

  }

  

  //print out each message to make sure it worked

  Serial.println("");

  Serial.println(message1);

  Serial.println(message2);

}

void loop() {

 //do nothing

  delay(50);

}

Method 2 Setup

//Example code for testing a serial bluetooth device using Arduino and a serial terminal on a computer

void setup() {

  // set baud rate to match BT module

  Serial.begin(115200);

}

void loop() {

  

  String t; //string to hold data from BT module 

  while(Serial.available()) { //keep reading bytes while they are still more in the buffer

    t += (char)Serial.read(); //read byte, convert to char, and append it to string

  }

  

  if(t.length()) { //if string is not empty do the following

    

    if(t == "Hi Uno\r\n") { Serial.print("Hello Neil\n"); } //say hello

    else if(t == "Meaning of life?\r\n") { //find out the meaning of life

      delay(1000);

      Serial.print("Money. ");

      delay(1000);

      Serial.print("Guns. ");

      delay(1000);

      Serial.print("Hoes.\n");

      delay(1000);

      Serial.print("Arduino.\n");

   }

   else { Serial.print("Syntax Error\n"); } //send this for any other string

  }

   delay(20);

}