So I've posted about a similar project before, but have moved on and need a bit of advice. I have an arduino UNO, a DS18B20 probe, an LCD and an MDFLY 4CH Relay Control Board - Optical-Coupler Isolated. I have the programming now so the device will read which relay is on or off, the temp set so the the corresponding relay will turn ON or OFF at above or below a certain temp, but I cannot get them turn off in the middle ground.

Basically, I want the heater (relay2) to turn ON at 77 and turn OFF at 78 and the fan (relay1)to turn ON at 80 and OFF at 79. Right now the heater stays on until the fan turns on at 80.

Here is the code:

#include <OneWire.h>
#include <Wire.h>
#include <DallasTemperature.h>
#include <LiquidCrystal_I2C.h>

//RGBLED
int bluePin1 = 10;                        //Digital Pin for blue LED1 in RGB-LED
int redPin1 = 12;                         //Digital Pin for red LED1 in RGB-LED

int redIn1 = 0;
int blueIn1 = 2;

int redVal1;
int blueVal1;

//Relays
int relPin1 = 2;                        //Digital Pin Relay1
int relPin2 = 3;                        //Digital Pin Relay2

//Heating Status
int heat1Val;
#define BACKLIGHT_PIN 13
#define ONE_WIRE_BUS 7
LiquidCrystal_I2C lcd(0x20,20,4);  // set the LCD address to 0x20 for a 20 chars and 4 line display
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);

void setup() {
  Serial.begin(9600);
  sensors.begin();
  lcd.init();                      // initialize the lcd
  lcd.backlight();
  pinMode(relPin1, OUTPUT);      //Output Mode for Relay1
  pinMode(relPin2, OUTPUT);      //Output Mode for Relay2
}

void loop() {
  sensors.requestTemperatures();
  float temperature1 = sensors.getTempFByIndex(0);
  lcd.setCursor(0, 0);
  lcd.print("Johnson's Reef");
  lcd.setCursor(0, 1);
  lcd.print("Aquarium: ");
  lcd.print(sensors.getTempFByIndex(0));
  lcd.print(" F ");

  //HEATER
  if(temperature1 < 77)
  {
    redVal1 = 0;
    blueVal1 = 5;
    digitalWrite(relPin1, LOW);  //FAN
    digitalWrite(relPin2, HIGH); //HEATER
    lcd.setCursor(0, 2);
    lcd.print("Heater:   ON ");
    lcd.setCursor(0, 3);
    lcd.print("Fan:      OFF ");
  }
  //FAN
  else if(temperature1 > 80)
  {
    redVal1 = 150;
    blueVal1 = 0;
    digitalWrite(relPin1, HIGH);  //FAN
    digitalWrite(relPin2, LOW);  //HEATER
    lcd.setCursor(0, 2);
    lcd.print("Heater:   OFF ");
    lcd.setCursor(0, 3);
    lcd.print("Fan:      ON ");
  }
  

  {
    analogWrite(redPin1, redVal1);
    analogWrite(bluePin1, blueVal1);

  }
}

 

Ok, I added some additional code at the bottom and it seems to work now. Is there anything anyone can see that I should change for any reason?

#include <OneWire.h>
#include <Wire.h>
#include <DallasTemperature.h>
#include <LiquidCrystal_I2C.h>

//RGBLED
int bluePin1 = 10;  //Digital Pin for blue LED1 in RGB-LED
int redPin1 = 12;  //Digital Pin for red LED1 in RGB-LED

int redIn1 = 0;
int blueIn1 = 2;

int redVal1;
int blueVal1;

//Relays
int relPin1 = 2;  //Digital Pin Relay1
int relPin2 = 3;  //Digital Pin Relay2

//Heating Status
int heat1Val;
#define BACKLIGHT_PIN 13
#define ONE_WIRE_BUS 7
LiquidCrystal_I2C lcd(0x20,20,4);  // set the LCD address to 0x20 for a 20 chars and 4 line display
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);

void setup() {
  Serial.begin(9600);
  sensors.begin();
  lcd.init();  // initialize the lcd
  lcd.backlight();
  pinMode(relPin1, OUTPUT);  //Output Mode for Relay1
  pinMode(relPin2, OUTPUT);  //Output Mode for Relay2
}

void loop() {
  sensors.requestTemperatures();
  float temperature1 = sensors.getTempFByIndex(0);
  lcd.setCursor(0, 0);
  lcd.print("Johnson's Reef");
  lcd.setCursor(0, 1);
  lcd.print("Aquarium: ");
  lcd.print(sensors.getTempFByIndex(0));
  lcd.print(" F ");

  //HEATER
  if(temperature1 < 77)
  {
  redVal1 = 0;
  blueVal1 = 5;
  digitalWrite(relPin1, LOW);  //FAN
  digitalWrite(relPin2, HIGH); //HEATER
  lcd.setCursor(0, 2);
  lcd.print("Heater:  ON ");
  lcd.setCursor(0, 3);
  lcd.print("Fan:  OFF ");
  delay(5000);
  }
  //FAN
  else if(temperature1 > 80)
  {
  redVal1 = 150;
  blueVal1 = 0;
  digitalWrite(relPin1, HIGH);  //FAN
  digitalWrite(relPin2, LOW);  //HEATER
  lcd.setCursor(0, 2);
  lcd.print("Heater:  OFF ");
  lcd.setCursor(0, 3);
  lcd.print("Fan:  ON ");
  delay(5000);
  }
  //HEATER
  else if(temperature1 = 78)
  {
  redVal1 = 0;
  blueVal1 = 0;
  digitalWrite(relPin1, LOW);  //FAN
  digitalWrite(relPin2, LOW);  //HEATER
  lcd.setCursor(0, 2);
  lcd.print("Heater:  OFF ");
  lcd.setCursor(0, 3);
  lcd.print("Fan:  OFF ");
  delay(5000);
  }
  //FAN
  else if(temperature1 = 79)
  {
  redVal1 = 0;
  blueVal1 = 0;
  digitalWrite(relPin1, LOW);  //FAN
  digitalWrite(relPin2, LOW);  //HEATER
  lcd.setCursor(0, 2);
  lcd.print("Heater:  OFF ");
  lcd.setCursor(0, 3);
  lcd.print("Fan:  OFF ");
  delay(5000);
  }
  {
  analogWrite(redPin1, redVal1);
  analogWrite(bluePin1, blueVal1);

  }
}