tsop4838 - constant signaling

Other Hardware Sensors
1

Hi,

I am building an IR beacon and a receiving sensor for my robot.
I built the sender out of five IR LEDs a transistor and some caps.

As receiver I want to use two IR Receivers TSOP4838(http://www.produktinfo.conrad.com/datenblaetter/150000-174999/171115-da-01-en-IR_EMPFAENGER_MODUL_TSOP_4838__VIS.pdf) in tubes to get a directional sensor. (need to find the correct angle between them so they both receive if pointed directly to the beacon)
To not produce too much overhead and to get a (timing wise) steady signal I do not want to decode any IR remote signals. I just count rising or falling signals on external interrupt pins as long as I need the sensor. Then I compare the results from both sensors.

So far sender and both receivers work as long as I use the IRremote library for sending valid IR remote signals. When I simply generate a 38kHz modulated signal, the receivers seem to give up after some time. As far as I read that’s part of the logic for noise filtering.

What is required to bypass this and keep the sensors constantly outputting signals? I think it can be concluded from the statements at the end of page 5. But I have difficoulties stranslating it into code.
Especially combining the modulation and the signaling. I think I don't get very far here with the tone library.

Thanks
Robert

Code of the receiver/sensor:

volatile long counter0 = 0;
volatile long counter1 = 0;
long wait = millis();
long countexp0 = 0;
long countexp1 = 0;

void setup()
{
  Serial.begin(115200);
  attachInterrupt(1, count1, FALLING);
  attachInterrupt(0, count0, FALLING);
  pinMode(2,INPUT_PULLUP);
  pinMode(3,INPUT_PULLUP);

}

void loop()
{
  if (millis() - wait > 100){
  countexp0 = counter0;
  countexp1 = counter1;
  counter0 = 0;
  counter1 = 0;
  
  Serial.print(countexp0);
  Serial.print(",");
  Serial.println(countexp1);

  wait = millis();
  }
}

void count1()
{
  counter1++;
}
void count0()
{
  counter0++;
}

The sender code which works:

#include <IRremote.h>

IRsend irsend;

void setup()
{}

void loop() {
      irsend.sendRC6(0xa90, 50);
}

Code of the sender with only the modulated signal (it will be a dedicated sender, so no fancy things with timer or interrupts are needed):

void setup ()
{
tone (3, 38000);
}
void loop () {}
2

OK, I now do it like this:

#define IRledPin 3

void setup (){}

void loop() {

  for(int i = 0; i <= 10; i++) {
    digitalWrite(IRledPin, HIGH);
    delayMicroseconds(13);
    digitalWrite(IRledPin, LOW);
    delayMicroseconds(13);
  }
  delayMicroseconds(3000); // sometimes the sensors don't resync if the delay is shorter
}

It works. But certainly isn't the optimum.

If someone has a better idea or other experience which may help .. it's very welcome.

Thanks
Robert