"If/else" code does not work on relay

[nuggexts]

Basically, this project aims to control a relay with a temperature. What I would like to do is when the temperature is below 38°C, the relay turns on and when the temperature exceeds 38°C, it will turn off. But, what happens is that the relay doesn't turn off even if the temperature exceeds 38°C.

For reference, I am using DHT11 for the temperature sensor. The setup is working just fine, it's just the condition where I'm having problems

Here's the code:

#include <Wire.h>
#include <DHT.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,  16, 2);

#define DHTPIN 7
#define DHTTYPE DHT11

int relay1 = 3;
int relay2 = 4;
int temp = 7;

DHT dht(DHTPIN, DHTTYPE);

void setup() {

Serial.begin(9600);

pinMode(relay1, OUTPUT);
pinMode(relay2, OUTPUT);

dht.begin();

lcd.init();
lcd.clear();
lcd.backlight();

}

void loop() {

  one();
//relay and motion connection
  delay(2000);
  }
  void one() {
    float dhtHumidity = dht.readHumidity();
    float dhtTemperature = dht.readTemperature();

    delay(1000);

  lcd.setCursor(0,0);

  lcd.print("Temp: ");
  lcd.print(dhtTemperature);
  lcd.print(" C");

  lcd.setCursor(0,1);
  lcd.print("Humid: ");
  lcd.print(dhtHumidity);
  lcd.print(" H");
  }

  void two() {
    temp = dht.readTemperature();
      if (temp < 38) {
      digitalWrite(relay1, LOW);
      }
      else {
      digitalWrite(relay1, HIGH);
      }
     }

Note:

1. The LCD Display is working just fine as well.
2. I accidentally bought a 2 channel relay, but I will not use the 2nd channel.

[anshu]

Maybe because the code to trigger the relay is under function "two()" which is never called?

[nuggexts]

Hi! I'm kind of new to Arduino language (I'm doing it just for a project) so I kind of don't get what you meant by "never called"

[anshu]

Based on the code you posted

#include <Wire.h>
#include <DHT.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,  16, 2);

#define DHTPIN 7
#define DHTTYPE DHT11

int relay1 = 3;
int relay2 = 4;
int temp = 7;

DHT dht(DHTPIN, DHTTYPE);

void setup() {

Serial.begin(9600);

pinMode(relay1, OUTPUT);
pinMode(relay2, OUTPUT);

dht.begin();

lcd.init();
lcd.clear();
lcd.backlight();

}

void loop() {

  one();  //Function controlling LCD is called here
  two(); //Function switching the relay is called here
  delay(2000);
  }
  void one() {
    float dhtHumidity = dht.readHumidity();
    float dhtTemperature = dht.readTemperature();

    delay(1000);

  lcd.setCursor(0,0);

  lcd.print("Temp: ");
  lcd.print(dhtTemperature);
  lcd.print(" C");

  lcd.setCursor(0,1);
  lcd.print("Humid: ");
  lcd.print(dhtHumidity);
  lcd.print(" H");
  }

  void two() {
    temp = dht.readTemperature();
      if (temp < 38) {
      digitalWrite(relay1, LOW);
      }
      else {
      digitalWrite(relay1, HIGH);
      }
     }

[nuggexts]

Thanks! It solved my problem, I know understand that I also have to declare "two()" after void loop