Copy and paste the code below into the Arduino Editor, then compile and upload it to your board. 

Download: file
/* CIRC17 - IR Replay
 * Requires: IRLib 2.x Library
 * record.ino by Chris Young
 * modified by Brent Rubell for Adafruit Industries for the for the Metro (and Metro Express) Experimenters Guide.  Support Open Source, buy Adafruit!

/* IRLib */
#include <IRLibDecodeBase.h>  //We need both the coding and
#include <IRLibSendBase.h>    // sending base classes
#include <IRLib_P01_NEC.h>    //Lowest numbered protocol 1st
#include <IRLib_P02_Sony.h>   // Include only protocols you want
#include <IRLib_P03_RC5.h>
#include <IRLib_P04_RC6.h>
#include <IRLib_P05_Panasonic_Old.h>
#include <IRLib_P07_NECx.h>
#include <IRLib_HashRaw.h>    //We need this for IRsendRaw
#include <IRLibCombo.h>       // After all protocols, include this
// All of the above automatically creates a universal decoder
// class called "IRdecode" and a universal sender class "IRsend"
// containing only the protocols you want.
// Now declare instances of the decoder and the sender.
IRdecode myDecoder;
IRsend mySender;

// Include a receiver either this or IRLibRecvPCI or IRLibRecvLoop
#include <IRLibRecv.h>
IRrecv myReceiver(2); //pin number for the receiver

// Storage for the recorded code
uint8_t codeProtocol;  // The type of code
uint32_t codeValue;    // The data bits if type is not raw
uint8_t codeBits;      // The length of the code in bits

//These flags keep track of whether we received the first code 
//and if we have have received a new different code from a previous one.
bool gotOne, gotNew; 

/* Buttons */ 
// button -> pin number
const int playBtn = 8;
const int recBtn = 9;
// hold the button states 
int playBtnState = 0;
int recBtnState = 0;

// status LED
const int ledPin = 13;

void setup() {
  gotOne=false; gotNew=false;
  /* BTNS AND LED */
  pinMode(ledPin, OUTPUT);
  digitalWrite(ledPin, LOW);
  pinMode(playBtn, INPUT);
  pinMode(recBtn, INPUT);
  Serial.println(F("Send a code from your remote and we will record it."));
  Serial.println(F("Type any character and press enter. We will send the recorded code."));
  Serial.println(F("Type 'r' special repeat sequence."));
  myReceiver.enableIRIn(); // Start the receiver

// Stores the code for later playback
void storeCode(void) {
  gotNew=true;    gotOne=true;
  codeProtocol = myDecoder.protocolNum;
  Serial.print(F("Received "));
  if (codeProtocol==UNKNOWN) {
    Serial.println(F(" saving raw data."));
    codeValue = myDecoder.value;
  else {
    if (myDecoder.value == REPEAT_CODE) {
      // Don't record a NEC repeat value as that's useless.
      Serial.println(F("repeat; ignoring."));
    } else {
      codeValue = myDecoder.value;
      codeBits = myDecoder.bits;
    Serial.print(F(" Value:0x"));
    Serial.println(codeValue, HEX);
void sendCode(void) {
  if( !gotNew ) {//We've already sent this so handle toggle bits
    if (codeProtocol == RC5) {
      codeValue ^= 0x0800;
    else if (codeProtocol == RC6) {
      switch(codeBits) {
        case 20: codeValue ^= 0x10000; break;
        case 24: codeValue ^= 0x100000; break;
        case 28: codeValue ^= 0x1000000; break;
        case 32: codeValue ^= 0x8000; break;
  if(codeProtocol== UNKNOWN) {
    //The raw time values start in decodeBuffer[1] because
    //the [0] entry is the gap between frames. The address
    //is passed to the raw send routine.
    //This isn't really number of bits. It's the number of entries
    //in the buffer.
    Serial.println(F("Sent raw"));
  if(codeProtocol==UNKNOWN) return;
  Serial.print(F("Sent "));
  Serial.print(F(" Value:0x"));
  Serial.println(codeValue, HEX);

void loop() {

  recBtnState = digitalRead(recBtn);
  playBtnState = digitalRead(playBtn);
  if(recBtnState == HIGH ) {
    digitalWrite(ledPin, LOW);
    // Re-enable receiver
    digitalWrite(ledPin, HIGH);

  if(playBtnState == HIGH) {
    // check for stored signal
    if(gotOne) {
      // send the IR Code
      // re-enable receiver
      digitalWrite(ledPin, LOW);

Not Working?

I don't see the LED lighting up

Try opening the Arduino Serial Monitor. There are Serial.print() statements in this code to help you debug.

I can receive but not send IR signals

Make sure your NPN Transistor is hooked up correctly, it is required for this circuit.

This guide was first published on Aug 18, 2017. It was last updated on Aug 18, 2017.

This page (Code) was last updated on Feb 16, 2021.

Text editor powered by tinymce.