Code to trigger photos with arduino (ESP8266) and infrared to control a Nikon D5300.

Nikon_D5300_ESP8266.ino

// inspiration: https://www.christidis.info/index.php/personal-projects/arduino-nikon-infrared-command-code

const int LEDpin = D3;
const int delay_us = 13; // 38 KHz

int i;

void setup() {
  pinMode(LEDpin, OUTPUT);
}

void loop() {
  takePhoto();
  delay(1000);
}


void takePhoto(void) {
  for (i = 0; i < 76; i++) {
    digitalWrite(LEDpin, HIGH);
    delayMicroseconds(delay_us);
    digitalWrite(LEDpin, LOW);
    delayMicroseconds(delay_us);
  }

  delayMicroseconds(27880);

  for (i = 0; i < 16; i++) {
    digitalWrite(LEDpin, HIGH);
    delayMicroseconds(delay_us);
    digitalWrite(LEDpin, LOW);
    delayMicroseconds(delay_us);
  }

  delayMicroseconds(1486);

  for (i = 0; i < 16; i++) {
    digitalWrite(LEDpin, HIGH);
    delayMicroseconds(delay_us);
    digitalWrite(LEDpin, LOW);
    delayMicroseconds(delay_us);
  }

  delayMicroseconds(3484);

  for (i = 0; i < 16; i++) {
    digitalWrite(LEDpin, HIGH);
    delayMicroseconds(delay_us);
    digitalWrite(LEDpin, LOW);
    delayMicroseconds(delay_us);
  }
}

Schematics example:
https://cdn.instructables.com/FGC/3H3P/IJAACJL3/FGC3H3PIJAACJL3.LARGE.jpg

Logic analyser visualization (top = pulsed light // bottom = envelop):