Tuesday, January 15, 2013

Bluetooth Tutorial 1


Introduction:
The bluetooth shield used in this project is a great way to detach the Arduino from your computer. What is even better, is that the shield allows you to control your arduino from your mobile phone or other bluetooth enabled device through simple Serial commands. In this tutorial we will connect a Grove Chainable RGB LED to the bluetooth shield directly, and send simple commands using the Bluetooth SPP app on a Samsung Galaxy S2 to change the colour of the LED (Red , Green and Blue)



Parts Required:
Freetronics Eleven or any compatible Arduino.
Bluetooth shield
Grove Chainable RGB LED
Grove Wire connectors




The Video:





The Arduino Sketch:








Arduino Code:
You can download the Arduino IDE from this site.


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/* This project combines the code from a few different sources.
This project was put together by ScottC on the 15/01/2013
http://arduinobasics.blogspot.com/

Bluetooth slave code by Steve Chang - downloaded from :
http://www.seeedstudio.com/wiki/index.php?title=Bluetooth_Shield

Grove Chainable RGB code can be found here :
http://www.seeedstudio.com/wiki/Grove_-_Chainable_RGB_LED#Introduction

*/

#include <SoftwareSerial.h> //Software Serial Port

#define uint8 unsigned char
#define uint16 unsigned int
#define uint32 unsigned long int

#define RxD 6 // This is the pin that the Bluetooth (BT_TX) will transmit to the Arduino (RxD)
#define TxD 7 // This is the pin that the Bluetooth (BT_RX) will receive from the Arduino (TxD)

#define DEBUG_ENABLED 1


int Clkpin = 9; //RGB LED Clock Pin (Digital 9)
int Datapin = 8; //RGB LED Data Pin (Digital 8)

SoftwareSerial blueToothSerial(RxD,TxD);

/*----------------------SETUP----------------------------*/
void setup() {
Serial.begin(9600); // Allow Serial communication via USB cable to computer (if required)
pinMode(RxD, INPUT); // Setup the Arduino to receive INPUT from the bluetooth shield on Digital Pin 6
pinMode(TxD, OUTPUT); // Setup the Arduino to send data (OUTPUT) to the bluetooth shield on Digital Pin 7
pinMode(13,OUTPUT); // Use onboard LED if required.
setupBlueToothConnection(); //Used to initialise the Bluetooth shield

pinMode(Datapin, OUTPUT); // Setup the RGB LED Data Pin
pinMode(Clkpin, OUTPUT); // Setup the RGB LED Clock pin

}

/*----------------------LOOP----------------------------*/
void loop() {
digitalWrite(13,LOW); //Turn off the onboard Arduino LED
char recvChar;
while(1){
if(blueToothSerial.available()){//check if there's any data sent from the remote bluetooth shield
recvChar = blueToothSerial.read();
Serial.print(recvChar); // Print the character received to the Serial Monitor (if required)

//If the character received = 'r' , then change the RGB led to display a RED colour
if(recvChar=='r'){
Send32Zero(); // begin
DataDealWithAndSend(255, 0, 0); // first node data
Send32Zero(); // send to update data
}

//If the character received = 'g' , then change the RGB led to display a GREEN colour
if(recvChar=='g'){
Send32Zero(); // begin
DataDealWithAndSend(0, 255, 0); // first node data
Send32Zero(); // send to update data
}

//If the character received = 'b' , then change the RGB led to display a BLUE colour
if(recvChar=='b'){
Send32Zero(); // begin
DataDealWithAndSend(0, 0, 255); // first node data
Send32Zero(); // send to update data
}
}

//You can use the following code to deal with any information coming from the Computer (serial monitor)
if(Serial.available()){
recvChar = Serial.read();

//This will send value obtained (recvChar) to the phone. The value will be displayed on the phone.
blueToothSerial.print(recvChar);
}
}
}


//The following code is necessary to setup the bluetooth shield ------copy and paste----------------
void setupBlueToothConnection()
{
blueToothSerial.begin(38400); //Set BluetoothBee BaudRate to default baud rate 38400
blueToothSerial.print("\r\n+STWMOD=0\r\n"); //set the bluetooth work in slave mode
blueToothSerial.print("\r\n+STNA=SeeedBTSlave\r\n"); //set the bluetooth name as "SeeedBTSlave"
blueToothSerial.print("\r\n+STOAUT=1\r\n"); // Permit Paired device to connect me
blueToothSerial.print("\r\n+STAUTO=0\r\n"); // Auto-connection should be forbidden here
delay(2000); // This delay is required.
blueToothSerial.print("\r\n+INQ=1\r\n"); //make the slave bluetooth inquirable
Serial.println("The slave bluetooth is inquirable!");
delay(2000); // This delay is required.
blueToothSerial.flush();
}


//The following code snippets are used update the colour of the RGB LED-----copy and paste------------
void ClkProduce(void){
digitalWrite(Clkpin, LOW);
delayMicroseconds(20);
digitalWrite(Clkpin, HIGH);
delayMicroseconds(20);
}

void Send32Zero(void){
unsigned char i;
for (i=0; i<32; i++){
digitalWrite(Datapin, LOW);
ClkProduce();
}
}

uint8 TakeAntiCode(uint8 dat){
uint8 tmp = 0;
if ((dat & 0x80) == 0){
tmp |= 0x02;
}

if ((dat & 0x40) == 0){
tmp |= 0x01;
}

return tmp;
}

// gray data
void DatSend(uint32 dx){
uint8 i;
for (i=0; i<32; i++){
if ((dx & 0x80000000) != 0){
digitalWrite(Datapin, HIGH);
} else {
digitalWrite(Datapin, LOW);
}

dx <<= 1;
ClkProduce();
}
}

// data processing
void DataDealWithAndSend(uint8 r, uint8 g, uint8 b){
uint32 dx = 0;

dx |= (uint32)0x03 << 30; // highest two bits 1,flag bits
dx |= (uint32)TakeAntiCode(b) << 28;
dx |= (uint32)TakeAntiCode(g) << 26;
dx |= (uint32)TakeAntiCode(r) << 24;

dx |= (uint32)b << 16;
dx |= (uint32)g << 8;
dx |= r;

DatSend(dx);
}

The code above was formatted using hilite.me

Notes:
You don't need to download a library to get this project running. But if you plan to use bluetooth shields to get 2 Arduinos to communicate to each other, then I would advise that you download the library files (which are just examples) from the Seeedstudio site : here.

Visit this site to setup your phone or laptop for bluetooth communication to the shield - here

The app used on my Samsung Galaxy S2 phone was "Bluetooth SPP"

You will initially need to enter a pin of '0000' to establish a connection to the Bluetooth shield - which will appear as "SeeedBTSlave" or whatever text you place on line 90 of the Arduino code above.





Warning !

Not all phones are compatible with the bluetooth shield.
If you have used this shield before - please let me know what phone you used - so that we can build a list and inform others whether their phone is likely to work with this project or not. Obviously - those phones that do not have bluetooth within - will not work :).
And I have not tried any other apps either

I got it to work very easily with my Samsung Galaxy S2 using the free Bluetooth SPP app from the google play store.

This was fun, but I want to make my own app !
Have a look at my latest 4-part tutorial which takes you step-by-step through the process of building your own app using the Processing/Android IDE.
You can build your own GUI interface on your Android Phone and get it to communicate via Bluetooth to your Arduino/Bluetooth Shield. Click on the links below for more information:




 
 



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