IR Transmitter not working for sending signal to Air Conditioning

Using Arduino Sensors
1

Greetings to all of you brilliant people,

I am humbly asking for help with my Final Year Project. My IR LED transmitter does not want to send the signal to AC. I even turn on my phone's camera to see if there is any flickering light through my camera, but there is none. I have had to debug this problem for almost ten months now, and I am at a dead end. My coding has no problems because it can upload to my Arduino Mega.

Btw, I also using TSOP1738 for decoding a signal from AC's remote control and all the outputs seem working for me. Again, I need your help to get IR LED Transmitter to be working.

below is my sketch circuit:
Circuit

And below is my coding part:

#include <IRremote.hpp>
#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include "DHT.h"
#include <IRremote.h>
IRsend irsend;

#define OLED_MOSI  3
#define OLED_CLK   4
#define OLED_DC    5
#define OLED_CS    6
#define OLED_RESET 7
Adafruit_SSD1306 display(OLED_MOSI, OLED_CLK, OLED_DC, OLED_RESET, OLED_CS);
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
#define SSD1306_LCDHEIGHT 64

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
//#define OLED_RESET     4 // Reset pin # (or -1 if sharing Arduino reset pin)
//Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

#define DHTPIN 48
#define DHTTYPE DHT22   // DHT 22  (AM2302), AM2321
DHT dht(DHTPIN, DHTTYPE);

#define PIEZO 8
#define ALARM  1000

#define LED 40

int Sound[] = {ALARM, ALARM};
int SoundNoteDurations[] = {4, 4};

#define playSound() playMelody(Sound, SoundNoteDurations, 2)

char inChar;
String inString;
#define Desired_temperature 23

int AC_Temp;
char temp_error = 2;
int Pev_value;
boolean AC = false;

void setup() {
  Serial.begin(9600);
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for (;;); // Don't proceed, loop forever
  }
  display.clearDisplay();
  dht.begin();
  pinMode(LED, OUTPUT);
}

void loop() {
  
  // Wait a few seconds between measurements.
  //delay(2000);

  // Reading temperature or humidity takes about 250 milliseconds!
  // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
  float h = dht.readHumidity();
  // Read temperature as Celsius (the default)
  float t = dht.readTemperature();
  // Read temperature as Fahrenheit (isFahrenheit = true)
  float f = dht.readTemperature(true);

  // Check if any reads failed and exit early (to try again).
  if (isnan(h) || isnan(t) || isnan(f)) {
    Serial.println(F("Failed to read from DHT sensor!"));
    return;
  }

  // Compute heat index in Fahrenheit (the default)
  float hif = dht.computeHeatIndex(f, h);
  // Compute heat index in Celsius (isFahreheit = false)
  float hic = dht.computeHeatIndex(t, h, false);

  if (hic >= 40) {
    displayOled();
    playSound();
  }
  else {
    displayOled();
    sendACsignal(); /***********Calling Send Signal to A/C Class Module**********/
    noTone(PIEZO);
  }

  Serial.print(F("Temperature: "));
  Serial.print(t);
  Serial.print(F("°C | Humidity: "));
  Serial.print(h);
  Serial.print(F("% "));
  Serial.print(F("  | Heat index: "));
  Serial.print(hic);
  Serial.print(F("°C | AC Temp: "));
  Serial.println(AC_Temp);                             
  delay(18000);
  
  digitalWrite(LED, HIGH);
  delay(200);
  digitalWrite(LED, LOW);
  delay(50);
  digitalWrite(LED, HIGH);
  delay(200);
   digitalWrite(LED, LOW);
  delay(50);
  digitalWrite(LED, HIGH);
  delay(200);
  digitalWrite(LED, LOW);
  
  delay(18000);
}

/***********OLED Display Module**********/
void displayOled() {

  // Read humidity
  float h = dht.readHumidity();
  // Read temperature as Celsius (the default)
  float t = dht.readTemperature();
  // Read temperature as Fahrenheit (isFahrenheit = true)
  float f = dht.readTemperature(true);
  // Compute heat index in Fahrenheit (the default)
  float hif = dht.computeHeatIndex(f, h);
  // Compute heat index in Celsius (isFahreheit = false)
  float hic = dht.computeHeatIndex(t, h, false);

  display.clearDisplay();
  display.setTextColor(WHITE);
  display.setTextSize(0.5);
  display.setCursor(0, 0);
  display.print("Temparature:");
  display.setCursor(77,0);
  display.print(t);
  display.print((char)247);
  display.print("C");
  display.setCursor(0, 10);
  display.print("Humidity   :");
  display.setCursor(77, 10);
  display.print(h);
  display.print(" %"); // degree symbol
  display.setCursor(0, 20);
  display.print("Heat Index :");
  display.setCursor(77, 20);
  display.print(hic);
  display.print((char)247); // degree symbol
  display.print("C");
  display.display();
  delay(18000);
}

/***********Send Signal to A/C Module**********/
void sendACsignal(){
float t = dht.readTemperature()+temp_error;
int khz = 38; // 38kHz carrier frequency for the NEC protocol
unsigned int   ACon[]={3200,1550, 450,400, 450,1100, 450,400, 450,350, 450,1150, 450,400, 450,1150, 450,350, 450,400, 450,1150, 450,1150, 450,1150, 450,350, 450,1150, 450,400, 400,1150, 450,1150, 450,1150, 450,400, 450,350, 450,400, 450,350, 450,1150, 450,1150, 450,400, 450,1150, 450,1150, 450,350, 450,400, 450,1100, 450,400, 450,350, 450,1150, 450,400, 450,350, 450,1150, 450,1150, 450,400, 450,1150, 450,1100, 500,1100, 500,1150, 450,1100, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,400, 450,350, 450,400, 450,350, 450,400, 450,350, 450};  
unsigned int  ACoff[]={3200,1600, 450,350, 450,1150, 450,400, 400,400, 450,1150, 450,350, 450,1150, 450,400, 400,400, 450,1150, 450,1150, 450,1150, 450,400, 400,1150, 450,400, 400,1200, 400,1200, 400,1200, 400,400, 450,350, 450,400, 450,400, 400,1200, 400,1200, 400,400, 450,1150, 400,1200, 400,450, 400,400, 400,1200, 400,400, 450,400, 400,1150, 450,400, 450,350, 450,1150, 450,1150, 450,400, 400,1200, 400,1200, 400,1200, 400,1200, 400,1200, 400,1200, 400,1200, 400,1150, 450,1150, 450,1150, 450,400, 400,400, 450,400, 400,400, 450,400, 400,400, 450};
unsigned int Temp16[]={3150,1600, 450,350, 450,1200, 400,400, 450,350, 450,1150, 450,400, 400,1200, 400,400, 450,400, 400,1200, 400,1200, 400,1200, 400,400, 450,1150, 450,350, 450,1150, 450,1200, 400,1150, 450,400, 400,400, 450,400, 400,400, 450,1150, 450,1150, 450,400, 400,1150, 450,1150, 450,400, 450,350, 450,1150, 450,400, 400,450, 400,1150, 450,400, 400,400, 450,1150, 450,1150, 450,400, 400,1150, 450,1150, 450,1200, 400,1200, 400,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,400, 400,400, 450,400, 400,400, 400,450, 400,400, 400};
unsigned int Temp17[]={3200,1600, 450,350, 450,1150, 450,400, 450,350, 450,1150, 450,400, 450,1100, 500,350, 450,400, 450,1100, 450,1150, 450,1150, 450,400, 450,1150, 450,350, 450,1150, 450,1150, 450,1150, 450,400, 450,350, 450,400, 450,350, 450,1150, 450,1150, 450,400, 450,1100, 450,1150, 450,400, 450,350, 450,1150, 450,400, 450,350, 450,1150, 450,400, 450,350, 450,1150, 450,1150, 450,400, 450,1150, 450,1150, 450,1150, 450,1150, 450,1100, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,400, 450,350, 450,400, 450,350, 450,400, 450,350, 450};
unsigned int Temp18[]={3200,1600, 450,350, 450,1150, 450,400, 450,350, 450,1150, 450,400, 450,1150, 450,350, 450,400, 450,1150, 450,1150, 450,1100, 450,400, 450,1150, 450,350, 450,1150, 450,1150, 450,1150, 450,400, 450,350, 450,400, 450,350, 450,1150, 450,1150, 450,400, 450,1150, 450,1100, 450,400, 450,350, 450,1150, 450,400, 450,350, 450,1150, 450,400, 450,350, 450,1150, 450,1150, 450,400, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1100, 450,1150, 450,1150, 450,1150, 450,1150, 450,400, 450,350, 450,400, 450,350, 450,400, 450,350, 450};
unsigned int Temp19[]={3150,1600, 400,400, 450,1150, 450,400, 400,400, 450,1150, 450,350, 450,1150, 450,400, 450,400, 400,1200, 400,1200, 400,1200, 400,400, 450,1150, 450,350, 450,1150, 450,1150, 450,1150, 450,350, 450,400, 450,350, 450,400, 450,1150, 450,1150, 400,400, 450,1150, 450,1150, 450,400, 400,400, 450,1150, 450,400, 400,400, 450,1150, 450,400, 400,400, 450,1150, 450,1150, 450,350, 450,1150, 450,1150, 450,1150, 450,1200, 400,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,350, 450,400, 450,350, 450,400, 450,350, 450,400, 450};
unsigned int Temp20[]={3200,1600, 450,350, 450,1150, 450,350, 450,400, 400,1200, 450,350, 450,1150, 450,400, 450,350, 450,1150, 450,1150, 450,1150, 450,400, 400,1200, 450,350, 450,1150, 450,1150, 450,1150, 450,350, 450,400, 400,400, 450,400, 450,1150, 400,1200, 400,400, 450,1150, 450,1150, 450,400, 400,400, 450,1150, 450,350, 500,350, 450,1150, 400,400, 450,400, 400,1200, 400,1200, 400,400, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 400,1200, 400,1200, 400,1200, 400,1200, 400,400, 450,400, 400,400, 450,400, 400,400, 450,400, 400};
unsigned int Temp21[]={3200,1550, 450,400, 450,1150, 450,350, 450,400, 400,1150, 500,350, 450,1150, 450,350, 450,400, 450,1150, 400,1200, 400,1200, 400,400, 450,1150, 450,400, 400,1200, 450,1100, 450,1200, 450,350, 450,350, 500,350, 450,350, 450,1150, 450,1150, 450,400, 450,1150, 400,1200, 450,350, 450,400, 400,1150, 450,400, 450,350, 450,1150, 500,350, 450,400, 400,1150, 450,1150, 450,400, 450,1150, 400,1200, 400,1200, 450,1100, 450,1150, 450,1200, 400,1150, 450,1150, 450,1150, 450,1150, 450,400, 450,350, 450,400, 400,400, 450,400, 400,400, 450};  
unsigned int Temp22[]={3150,1650, 450,350, 450,1150, 450,350, 450,400, 450,1150, 450,350, 450,1150, 450,400, 450,350, 450,1150, 450,1150, 450,1150, 450,400, 450,1150, 450,350, 450,1150, 450,1150, 450,1150, 450,350, 450,400, 450,350, 450,400, 450,1150, 450,1150, 450,350, 450,1150, 450,1150, 450,400, 450,350, 450,1150, 450,400, 450,350, 450,1150, 450,400, 400,400, 450,1150, 450,1150, 450,350, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,350, 450,400, 400,400, 450,400, 450,350, 450,400, 450};  
unsigned int Temp23[]={3200,1600, 400,400, 450,1150, 450,400, 400,400, 450,1150, 450,350, 450,1150, 450,400, 450,350, 450,1150, 450,1150, 450,1150, 450,400, 450,1150, 450,350, 450,1150, 450,1150, 450,1150, 450,400, 400,400, 450,400, 400,400, 450,1150, 450,1150, 450,350, 450,1150, 450,1150, 450,400, 450,350, 450,1150, 450,400, 450,350, 450,1150, 450,400, 450,350, 450,1150, 450,1150, 450,350, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,350, 450,400, 450,350, 450,400, 450,350, 450,400, 450};  
unsigned int Temp24[]={3200,1600, 400,400, 450,1150, 450,350, 450,400, 450,1150, 450,350, 450,1150, 450,400, 400,400, 450,1150, 450,1150, 450,1150, 450,400, 400,1200, 400,400, 450,1150, 450,1150, 450,1150, 400,400, 450,400, 400,450, 400,400, 400,1200, 400,1200, 400,400, 450,1150, 450,1150, 450,400, 400,400, 450,1150, 450,400, 400,400, 450,1150, 450,350, 450,400, 450,1150, 400,1200, 400,450, 400,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 400,1200, 400,400, 450,400, 400,400, 450,400, 400,400, 450,400, 400};  
unsigned int Temp25[]={3200,1600, 400,400, 450,1150, 450,400, 400,400, 450,1150, 450,400, 400,1150, 450,400, 400,400, 450,1150, 450,1150, 450,1150, 450,400, 400,1150, 450,400, 450,1150, 450,1150, 400,1200, 400,400, 450,400, 400,450, 400,400, 400,1200, 400,1200, 400,400, 450,1150, 450,1150, 450,350, 450,400, 450,1150, 450,350, 450,400, 450,1150, 400,450, 400,400, 400,1200, 450,1150, 450,350, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 400,1200, 450,1150, 450,350, 450,400, 450,350, 450,400, 400,400, 450,400, 400};  
unsigned int Temp26[]={3200,1600, 400,400, 450,1150, 400,450, 400,400, 400,1200, 400,400, 450,1150, 450,400, 400,400, 450,1150, 450,1150, 450,1150, 450,400, 400,1200, 400,400, 400,1200, 400,1200, 400,1200, 400,400, 450,400, 400,400, 450,400, 450,1150, 400,1200, 400,400, 450,1150, 450,1150, 400,450, 400,400, 400,1200, 400,400, 450,400, 450,1150, 400,400, 450,400, 400,1200, 400,1200, 400,400, 450,1150, 450,1150, 400,1200, 400,1200, 450,1150, 400,1150, 450,1200, 400,1200, 450,1150, 450,1150, 400,400, 450,400, 400,400, 450,400, 400,400, 450,400, 400};
unsigned int Temp27[]={3200,1600, 450,350, 450,1150, 450,400, 450,350, 450,1150, 450,400, 450,1100, 500,350, 450,400, 450,1100, 500,1100, 500,1100, 450,400, 450,1150, 450,350, 450,1150, 450,1150, 450,1150, 450,400, 450,350, 450,400, 450,350, 450,1150, 450,1150, 450,400, 400,1150, 450,1150, 450,400, 450,350, 450,1150, 450,400, 450,350, 450,1150, 450,400, 450,350, 450,1150, 450,1150, 450,400, 400,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,350, 450,400, 450,350, 450,400, 450,350, 450,400, 450};  
unsigned int Temp28[]={3150,1600, 450,350, 450,1150, 450,400, 400,400, 450,1150, 450,400, 400,1200, 400,400, 450,400, 400,1200, 400,1200, 400,1150, 450,400, 450,1150, 450,350, 450,1150, 450,1150, 450,1150, 450,400, 400,400, 450,400, 400,400, 450,1150, 450,1150, 450,400, 400,1150, 450,1150, 450,400, 450,350, 450,1150, 450,400, 450,350, 450,1150, 450,400, 400,400, 450,1150, 450,1150, 450,400, 400,1200, 400,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,350, 450,400, 450,400, 400,400, 450,350, 450,400, 450};
unsigned int Temp29[]={3150,1600, 400,400, 450,1150, 450,400, 400,400, 450,1150, 450,400, 400,1200, 400,400, 450,400, 400,1150, 450,1150, 450,1150, 450,400, 450,1150, 450,350, 450,1200, 400,1200, 400,1150, 450,400, 400,450, 400,400, 400,400, 450,1150, 450,1150, 450,400, 400,1200, 400,1150, 450,400, 450,350, 450,1150, 450,400, 450,350, 450,1150, 450,400, 450,350, 450,1150, 450,1150, 450,400, 400,1200, 400,1200, 400,1200, 400,1200, 400,1200, 400,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,400, 400,400, 450,400, 400,400, 450,400, 400,400, 450};
unsigned int Temp30[]={3200,1600, 400,400, 450,1150, 450,400, 400,400, 450,1150, 450,350, 450,1150, 450,400, 450,350, 450,1150, 450,1150, 450,1150, 450,400, 400,1200, 400,400, 450,1150, 450,1150, 450,1150, 450,400, 400,400, 450,400, 400,400, 450,1150, 450,1150, 450,350, 450,1150, 450,1150, 450,400, 450,400, 400,1200, 400,400, 400,400, 450,1150, 450,400, 400,400, 450,1150, 450,1150, 450,400, 400,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,1150, 450,350, 450,400, 450,350, 450,400, 450,350, 450,400, 450};

 if ((t <= (Desired_temperature-7)) && AC == true){ //20*=off If AC is turned on and temperature is less than 3 degree of Desired value #24 turn off
  irsend.sendRaw(ACoff, sizeof(ACoff) / sizeof(ACoff[0]), khz);  
  delay(3000);//Send signal to Turn Off the AC
  AC_Temp = 0; AC=false;
 }
 if ((t >= Desired_temperature+5) && AC == false){ //27*=on If AC is off and measured Temp is greater than Desired Temp
  irsend.sendRaw(ACon, sizeof(ACon) / sizeof(ACon[0]), khz); 
  delay(2000); //Send Signal to Turn On the AC 
  delay(3000);
  irsend.sendRaw(Temp23, sizeof(Temp23) / sizeof(Temp23[0]), khz); //Send signal to set 23*C
  AC_Temp = 23; AC=true;
 }
if ( t != Pev_value){ //Change the temperature only if the measured voltage value changes

    if (t == Desired_temperature+3){ //26*==23 If AC is ON and measured temp is very high than desired
       irsend.sendRaw(Temp23, sizeof(Temp23) / sizeof(Temp23[0]), khz); 
       delay(3000);//Send signal to set 25*C
      AC_Temp = 23; 
    }
    if (t == Desired_temperature+2){ //25*==24 If AC is ON and measured temp is very high than desired
       irsend.sendRaw(Temp24, sizeof(Temp24) / sizeof(Temp24[0]), khz); delay(2000);//Send signal to set 26*C
      AC_Temp = 24; 
    }
    if (t == 23 ){ //23*==23 If AC is ON and measured temp is desired value
      irsend.sendRaw(Temp23, sizeof(Temp23) / sizeof(Temp23[0]), khz); //Send signal to set 27*C
      AC_Temp = 23; 
    }
    if (t == Desired_temperature-6){ //16*=+26 If AC is ON and measured temp is low than desired value
      irsend.sendRaw(Temp26, sizeof(Temp26) / sizeof(Temp26[0]), khz); delay(2000);//Send signal to set 28*C
      AC_Temp = 26; 
    }
    if (t == Desired_temperature-3){ //20*=+25 If AC is ON and measured temp is low than desired value
      irsend.sendRaw(Temp25, sizeof(Temp25) / sizeof(Temp25[0]), khz); delay(2000);//Send signal to set 28*C
      AC_Temp = 25; 
    }
  }
  Pev_value = t;
}

/***********Buzzer Module**********/
void playMelody(int *melody, int *noteDurations, int notesLength)
{
  pinMode(PIEZO, OUTPUT);

  for (int thisNote = 0; thisNote < notesLength; thisNote++) {
    int noteDuration = 1000 / noteDurations[thisNote];
    tone(PIEZO, melody[thisNote], noteDuration);
    int pauseBetweenNotes = noteDuration * 1.30;
    delay(pauseBetweenNotes);
    noTone(PIEZO);
  }
}
2

I have to ask if your camera can see other IR remotes flickering?

3

The current limiting resistor of the LED is missing. Your PWM pin is probably fried if it was activated once.

You don't set the output pin for the irsend object, so the code doesn't know which pin to use for the LED.

4

Yes, it can, I tried with my AC, TV, and fan remote control, and I can see the flickering purple light through the camera.

5

I'll put the resistor, and if you don't mind me asking. If I define the pin for the LED, where and what the line of code will be put?

6

In the constructor of the irsend object.

7

So it will be something like this, right?

IRsend irsend 9;

correct me if I'm wrong.

8

You need parentheses around the argument. Study the library examples and documentation for the details.

9

Can you give a line of an example of which and where, because I'm still learning this language, and my knowledge is not strong. I'm currently researching and reading the documentation, example and library

10

IRsend irsend(9);

11

If I'm doing something like this

#define IR_SEND_PIN 9
IRsend irsend(IR_SEND_PIN);

is it also represents the same method, right?

12

Yes, it does the same as the define is interpreted by the precompiler the compiler will see exactly the same.

13

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