IR bridge that maps Samsung TV Vol+/Vol−/Mute to Integra/Onkyo AVR commands using an Adafruit Metro Mini 328 V2 and IRremote.

IRConvertor.ino

// Metro Mini 328 V2 / Arduino Uno
// Wiring:
//   PIN2 → TSOP38238 OUT
//   GND  → TSOP38238 GND
//   5V   → TSOP38238 VCC
//   5V   → 0.1µF capacitor → TSOP38238 VCC
//   PIN3 → 1kΩ → PN2222 base
//   GND  → PN2222 emitter
//   PN2222 collector → IR LED cathode (short lead)
//   IR LED anode (long lead) → 50Ω → 5V

#include <IRremote.hpp>

const uint8_t IR_RECEIVE_PIN = 2;     // TSOP38238 OUT
const uint8_t IR_SEND_PIN = 3;        // -> 1k -> PN2222 base
const uint8_t LED_PIN = LED_BUILTIN;  // On-board LED (D13 on Metro Mini/Uno)

// Samsung 32-bit raw values (as seen in ReceiveDump)
const uint32_t SAMSUNG_VOL_UP_RAW = 0xF8070707;
const uint32_t SAMSUNG_VOL_DOWN_RAW = 0xF40B0707;
const uint32_t SAMSUNG_MUTE = 0xF00F0707;

// Integra / Onkyo (NEC) address + commands
const uint16_t ONKYO_ADDR = 0x6DD2;
const uint8_t CMD_VOL_UP = 0x02;
const uint8_t CMD_VOL_DOWN = 0x03;
const uint8_t CMD_MUTE = 0x05;

// Rate limit so we don't spam the AVR (ms between transmissions).
// NEC frames are ~67 ms; 70–90 ms feels natural for volume ramp.
const uint16_t MIN_SEND_INTERVAL_MS = 800;
uint32_t lastSendMs = 0;

// Tiny, non-blocking LED pulse
inline void pulseLED(uint8_t ms = 10) {
  digitalWrite(LED_PIN, HIGH);
  delay(ms);  // 10 ms is short; safe here
  digitalWrite(LED_PIN, LOW);
}

inline bool canSendNow() {
  uint32_t now = millis();
  if (now - lastSendMs >= MIN_SEND_INTERVAL_MS) {
    lastSendMs = now;
    return true;
  }
  return false;
}

void setup() {
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW);

  // Start IR without library LED feedback; we control LED ourselves
  IrReceiver.begin(IR_RECEIVE_PIN, ENABLE_LED_FEEDBACK);
  IrSender.begin(IR_SEND_PIN);
  IrSender.enableIROut(38);  // NEC uses 38 kHz

  Serial.begin(115200);
  Serial.println(F("Samsung -> Integra volume translator with LED blinks"));
  Serial.println(F("Blink 1x = received any IR; Blink + another 1x = matched & re-sent"));
}

void loop() {
  // blinkOnce();
  if (!IrReceiver.decode()) return;

  Serial.println(F("Received Signal"));

  // Copy out what we need, then resume ASAP to keep receiver ready
  auto d = IrReceiver.decodedIRData;
  bool isSamsung = (d.protocol == SAMSUNG);
  uint32_t raw = d.decodedRawData;
  bool held = d.flags & IRDATA_FLAGS_IS_REPEAT;

  if (isSamsung) {
    bool matched = true;
    uint16_t command = 0;
    uint8_t repeats = held ? 2 : 1;  // ramp when holding

    switch (raw) {
      case SAMSUNG_VOL_UP_RAW:
        // send Onkyo/Integra VOL+
        command = CMD_VOL_UP;
        Serial.println(F("Matched: SAMSUNG VOL+ -> Sent ONKYO VOL+"));
        break;
      case SAMSUNG_VOL_DOWN_RAW:
        // send Onkyo/Integra VOL-
        command = CMD_VOL_DOWN;
        Serial.println(F("Matched: SAMSUNG VOL- -> Sent ONKYO VOL-"));
        break;
      case SAMSUNG_MUTE:
        command = CMD_MUTE;
        Serial.println(F("Matched: SAMSUNG MUTE -> Sent ONKYO MUTE"));
        break;
      default:
        // Not a key we care about; ignore.
        matched = false;
        break;
    }

    if (matched && canSendNow()) {
      // avoid IR interference
      delay(100);
      IrSender.sendNEC(ONKYO_ADDR, command, 0);
      delay(200);
      Serial.println(F("Signal Sent"));
    }
  }
  IrReceiver.resume();  // free the receiver quickly
}