SONY SIRC Remote Controlled device using PIC Micro-controller and mikroC

In this article, we are going to make our own remote-controlled device using SONY SIRC remote protocol. In the previous article, we have learned the basic pattern of this protocol and now we will use that in our circuit. We’ll use PIC12F675 micro-controller and mikroC Pro for PIC compiler. Let’s start!

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About SONY SIRC:

In my previous article, I’ve explained this protocol. Please read that article first to learn about SONY SIRC. SIRC protocol is one of the most common protocols in the remote-controlled system. This protocol uses a start bit, then a command and then an address bit. All these are transmitted at 40KHz modulation. A remote sensor is used to receive that modulated signal and decode the pattern. After that, micro-controllers are used further to decode the command and address from that received signal.

Circuit Diagram:

MikroC Code with the library:

Here is the library of SONY SIRC remote decoder. I used mikroC pro for PIC with valid license. If you are having problem building the hex let me know.

sbit ir_rx at GP3_bit; // Sensor pin

// function prototypes
void get_mark_time(void);


// global variables
unsigned char counter = 0;
unsigned char bitcount;
unsigned char ir_address;
unsigned char ir_command;
unsigned int mark_time;

void interrupt() iv 0x0004 ics ICS_AUTO
{
    if (TMR0IF_bit)
    {
        counter++;              // increment counter
        TMR0IF_bit = 0;         // Clear Timer0 overflow interrupt flag
    }
}

void main() 
{
  CMCON = 0x07;                 // disable comparator
  ANSEL = 0x00;                 // disable analogue
  OPTION_REG = 0x03;            // TMR0 prescaler set to 1:16
  TRISIO = 0x08;                // IR GP3 = input, rest output
  GPIO = 0x00;                  // all outputs off
  
  // start timer 0 counting
  GIE_bit = 1;                  // Global interrupt enable
  T0IE_bit = 1;                 // Enable Timer0 overflow interrupt
  
  while(1)
  {
      
      
      ir_command = 0;
      ir_address = 0;
      get_mark_time();
      if ((mark_time > 120) && (mark_time < 200))  // set the frequency limit
      {
          for(bitcount = 0 ; bitcount < 7 ; bitcount++)
          {
              get_mark_time();                               // get a Sony IR bit
              ir_command >>= 1;                              // shift
              ir_command &= 0x7f;                            // top bit zero
              if (mark_time > 0x40)
              {
                  ir_command ^= 0x80;                        // top bit 1
              }
          }
          ir_command >>= 1;                                  // shift 1 unused bit
          ir_command &= 0x7F;                                // clear top bit

          for(bitcount = 0 ; bitcount < 5 ; bitcount++)
          {
              get_mark_time();                               // get a Sony IR bit
              ir_address >>= 1;                              // shift
              ir_address &= 0x7f;                            // top bit zero
              if (mark_time > 0x40)
              {
                  ir_address ^= 0x80;                        // top bit 1
              }
          }
          ir_address >>= 3;                                  // shift 3 unused bits
          ir_address &= 0x1F;                                // clear top 3 bits
      }
      
      
      
      
      
      
      if(ir_address == 1)
      {                                                      // TV
          if(ir_command == 0)
          {                                                  // button 1
              GP0_bit = ~GP0_bit;
          }
          if(ir_command == 1)
          {                                                  // button 2
              GP1_bit = ~GP1_bit;
          }
          if(ir_command == 2)
          {                                                  // button 3
              GP2_bit = ~GP2_bit;
          }
          
          Delay_ms(200);                                     // avoid double toggle
      }
      
      
      
      
      
      
  }
}

// get time of mark, then ignore space
void get_mark_time(void)
{
    while(ir_rx);                           // wait for a mark
    counter=0;
    TMR0 = 0;
    while(!ir_rx);                          // wait for space
    mark_time = (counter << 8) + TMR0;      // collect integer mark time
}

Download the hex file instead.

Test result:

I’ve made a video for this purpose. Please play this video.

Conclusion: