Hello, I have been working on a project where I have rewired the IR receiver module of an existing device to connect to an arduino, the arduino then filters for certain commands, and consumes them, while repeating all other commands. The repeated commands are to be sent to the existing device through a direct connection. Currently, I am testing the concept between 2 arduino nanos, both running the same code, but I am still struggling to get this concept to work.

I'm not sure if I have missed an important #define somewhere that would cause this to work properly (see code below), but here are my observations:

1. The base signal of the real IR receiver is HIGH (~5v). The base signal coming out of my arduino's send pin is (~0.4v, which happens to match the unused pins).
2. The active signal of the real IR receiver drops LOW, with my slow multimeter it reads to an average of ~3.8v. The "active" signal coming from the arduino does not change.
3. It seems that

References for this behavior:
#1229

New features of version 3.x
...
Allows for the generation of non PWM signal to just simulate an active low receiver signal for direct connect to existent receiving devices without using IR.
...

https://wolfgang-ziegler.com/blog/faking-ir-signal-with-arduino

Here is my code. (note, some of the other includes I have tried, in combination, commented out)

(edit: I have adjusted the code to be functional, so that people in the future can use it as a reference)

#define USE_NO_SEND_PWM
#define USE_ACTIVE_LOW_OUTPUT_FOR_SEND_PIN 

#define IR_RECEIVE_PIN 5
#define IR_SEND_PIN 6


//it's critical for these definitions to be done before the library is included


#include <IRremote.hpp>

void setup()
{
  Serial.begin(115200);
  
  IrReceiver.begin(IR_RECEIVE_PIN, ENABLE_LED_FEEDBACK);
}
void loop() {
  if (IrReceiver.decode()) {
    //prints for debugging
    Serial.println(IrReceiver.decodedIRData.decodedRawData, HEX); // Print "old" raw data
    IrReceiver.printIRResultShort(&Serial); // Print complete received data in one line
    IrReceiver.printIRSendUsage(&Serial);   // Print the statement required to send this data

    IrSender.sendNEC(IrReceiver.decodedIRData.address, IrReceiver.decodedIRData.command, 3);
    Serial.println("Sent NEC signal");

    IrReceiver.restartAfterSend();

    IrReceiver.resume();
  }
}