//========================================================================================================
// Simple example of alive character sent to a BT receiver 
// Date 08/05/20220
// Rev. 0
//========================================================================================================
// Arduino UNO board
// Serial line toward PC for debugging purposes
// SoftwareSerial used to exchange data toward the BT (MIT AI2 code for the phone App)
// The circuit:
// RX is digital pin 2 (connect to TX of other device)
// TX is digital pin 3 (connect to RX of other device)
// it is supposed thet the HC05 (or HC06)shield is programmed with 9600 baud toward the Arduino
// (sometimes, by default, they are programmed @38400 : check before setting the myserial baudrate)
// The alive character shall be sent with a trailing CRLF characters pair, using a println(), because
// the MIT AI2 code requires a LF terminator
//========================================================================================================
#include <SoftwareSerial.h>
#define REFRESH 2000
#define RX 2
#define TX 3


 
SoftwareSerial myserial(RX,TX);

unsigned long parte = 0;
  

void setup(){
  Serial.begin(9600);
  myserial.begin(9600);
  parte = millis();  
}

void loop()
{
  DoMyStuff();
  if ((millis() - parte) >= (unsigned long)REFRESH)     // elapsed 2 seconds, then sends a $ to the phone (alive character)
     {
              parte = millis();                         // restarts the alive timer
              ToThePhone('$');                          // alive to the phone                            
     }
  }
/////////////////////////  Functions  /////////////////////////////////

void ToThePhone(char charaliv)         // Sends the alive
{
  Serial.println(charaliv);       // for debug purposes only, to be commented out when done
  myserial.println(charaliv);     // sends the alive char to the phone by the BT line  
}


//==========================================================================================
// mainn functions performed in the loop()
void DoMyStuff()
{}