Sunday, August 31, 2014

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

Sunday, August 10, 2014

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.

AT CommandREply from HC-06COMMENTs
ATOKUsed to verify communication
AT+VERSIONOKlinvorV1.8The firmware version
AT+NAMEmyBTOKsetnameSets the module name to “myBT”
AT+PIN1234OKsetPINSets the module PIN to 1234
AT+BAUD1OK1200Sets the baud rate to 1200
AT+BAUD2OK2400Sets the baud rate to 2400
AT+BAUD3OK4800Sets the baud rate to 4800
AT+BAUD4OK9600Sets the baud rate to 9600
AT+BAUD5OK19200Sets the baud rate to 19200
AT+BAUD6OK38400Sets the baud rate to 38400
AT+BAUD7OK57600Sets the baud rate to 57600
AT+BAUD8OK115200Sets the baud rate to 115200
AT+BAUD9OK230400Sets the baud rate to 230400
AT+BAUDAOK460800Sets the baud rate to 460800
AT+BAUDBOK921600Sets the baud rate to 921600
AT+BAUDCOK1382400Sets 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
  //Send command to set name of HC06 module, with the below command name will change to "forcetronics"
  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] =; //read in char
        if(count == 9) break; //after we get all 9 char break out of loop
  //Send AT command to change baud rate to 115200
  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] =; 
        if(count == 8) break; 
  //print out each message to make sure it worked

void loop() {
 //do nothing

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

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