← Back to Home

June 11, 2026

void setup() {
  // PB4 (Physical Pin 3) is Arduino pin 4
  pinMode(4, OUTPUT); 
}

void mark(uint32_t time) {
  // 38kHz carrier logic for 8MHz ATtiny85
  // Shifted to use Channel B for PB4 (OC1B) output
  TCCR1 = _BV(CTC1) | _BV(CS10);     // CTC mode, no prescaler
  GTCCR = _BV(PWM1B) | _BV(COM1B1);  // Enable PWM B, clear on match

  // 8,000,000 / 38,000 = 210.5
  OCR1C = 210; // Timer resets at 210 to hit 38kHz
  OCR1B = 105; // Duty cycle is exactly half of OCR1C (50%) for Channel B
  
  customDelay(time);
}

void space(uint32_t time) {
  TCCR1 = 0; // Turn off main timer
  GTCCR = 0; // Turn off PWM Channel B
  digitalWrite(4, LOW); // Ensure PB4 stays low
  
  customDelay(time);
}

// Handles durations longer than 16383us which delayMicroseconds fails at
void customDelay(uint32_t us) {
  while (us > 15000) {
    delayMicroseconds(15000);
    us -= 15000;
  }
  delayMicroseconds(us); // Handle the remainder
}

void loop() {
  for (uint8_t i = 0; i < totalCodes; i++) {
    
    // 1. Get pointer to the current code array
    const uint8_t* currentCode = (const uint8_t*)pgm_read_word(&(allCodes[i]));
    
    // 2. Get the length and base unit for this specific code
    uint8_t len = codeLengths[i];
    uint16_t baseUnit = baseUnits[i];

    // 3. Repeat each code exactly twice
    for (uint8_t rep = 0; rep < 2; rep++) {
      
      for (uint8_t j = 0; j < len; j++) {
        // Read the 8-bit multiplier from PROGMEM
        uint8_t multiplier = pgm_read_byte(&currentCode[j]);
        
        // Calculate actual duration
        uint32_t duration = (uint32_t)multiplier * baseUnit;

        if (j % 2 == 0) mark(duration); // Even = Pulse
        else space(duration);           // Odd = Gap
      }
      space(0); // Ensure off
      
      // Standard 150ms gap between identical blasts so the TV recognizes them
      delay(150); 
    }

    // 100ms gap before moving to the next TV brand
    delay(100); 
  }
  
  // No delay here; the list immediately starts over from the beginning
}

↑ Back to top