Introduction: ATtiny85 - Bluetooth

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In the last instructable I showed you how to program an ATiny85, in this instructable I will show you how to start serial communication with the ATiny85 over a Bluetooth network. For this instructable I will be using a HC05 Bluetooth module which can be purchased for cheap on eBay.

So lets get started....

Step 1: Tools and Components

Here is what you need -

Step 2: Circuit

Setup the connections between the ATiny and the Bluetooth as follows -

  • Bluetooth Module Rx --> ATiny85 Pin 1
  • Bluetooth Module Tx --> ATiny85 Pin 2
  • Bluetooth Module Gnd --> ATiny85 Pin 4
  • Bluetooth Module VCC --> ATiny85 Pin 8

Step 3: Code

Here is a test sketch you can run, connect a led at 6 and upload the code. Sending 1 from a serial terminal will turn on the LED and sending 0 will turn it off.

#include    //Software Serial Port
#define RxD 1
#define TxD 2
#define DEBUG_ENABLED  1
 
SoftwareSerial blueToothSerial(RxD,TxD);
int led = 4;
 
void setup() 
{ 
  pinMode(RxD, INPUT);
  pinMode(TxD, OUTPUT);
  setupBlueToothConnection();
  
  pinMode(led,OUTPUT);
  digitalWrite(led,HIGH);
 
} 
 
void loop() 
{ 
  char recvChar;
  while(1){
    //check if there's any data sent from the remote bluetooth shield
    if(blueToothSerial.available()){
      recvChar = blueToothSerial.read();
      
        if(recvChar == '1')
          digitalWrite(led,HIGH);  
       
        else
          digitalWrite(led,LOW); 
    }
  }
} 
 
void setupBlueToothConnection()
{
  blueToothSerial.begin(9600); //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=HC-05\r\n"); //set the bluetooth name as "HC-05"
  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 
  blueToothSerial.print("bluetooth connected!\n");
  
  delay(2000); // This delay is required.
  blueToothSerial.flush();
}