Controlling Home Ventilation Fan with Arduino UNO Rev.03, TMP36 and Bi-Stable Relay

In order to maintain a cozy and healthy indoor climate, a home ventilation fan controller is essential. It enables homeowners to control the ventilation and airflow in their houses, which can provide a number of significant advantages:

1. Improve indoor air quality: Improved indoor air quality is a result of proper ventilation, which helps get rid of pollutants including dust, allergens, volatile organic compounds (VOCs), and odors. A ventilation fan controller ensures that fresh air is consistently circulated throughout the house by managing the fan speed and timing, reducing the concentration of pollutants and raising indoor air quality.

2. Moisture Control: Excessive moisture in the house can result in mold, mildew, and other moisture-related problems, which can be harmful to both the residents’ health and the building’s structural integrity. By regulating fan speed either automatically or manually in response to moisture levels, a ventilation fan controller enables homeowners to manage humidity levels effectively. This lessens the possibility of mold growth by preventing moisture buildup.

3. Energy Efficiency: Homeowners can reduce the amount of energy used by their ventilation system by using a ventilation fan controller. Energy consumption can be decreased when full ventilation capacity is not needed by regulating the fan speed according to the particular requirements of each room or area. Over time, this may lead to energy savings and decreased electricity costs.

4. Comfort and Temperature Control: A ventilation fan controller can help control the temperature and the general comfort of a home in addition to maintaining air quality. It can help distribute cold air from air conditioning systems or improve natural ventilation for cooling by altering the fan speed and airflow. The occupants’ living space is made more comfortable by this control over air flow.

5. Noise reduction: Some ventilation fans produce a lot of noise, especially when they’re operating quickly. When noise reduction is required, such as during sleeping hours or when engaging in activities that call for little background noise, homeowners can use a fan controller to lower the fan speed.

One option for ventilation fan systems is to purchase those equipped with a heat exchanger, which can recover heat from the air being extracted from the house. This method is highly efficient, but it comes with a higher cost and installation complexity. In contrast, we have introduced a straightforward fan system that utilizes a humidity sensing device to decrease the airflow rate when the indoor humidity levels are low. The fan control mechanism involves using a relay to switch the fan on and off.

Required Components

1x Arduino UNO Rev.03

1x USB-B Cable

1x 5V relay

1x Alphanumeric LCD (16 x 2 Characters)

1x TMP36

1x Diode: 1N4007

1x 9V DC Fan

1x 9V Battery

1x 9V Battery Snap

1x BC547

Code

//https://www.eementor.co

//Libraries
#include <LiquidCrystal_I2C.h>
#include <Wire.h>

//Here, libraries are called

//Constants
#define TMP36 A0                     //Define analog pin 0 of UNO for TMP36’s data pin.
#define Relay 7                      //Define digital pin 7 of UNO for relay driving pin.
LiquidCrystal_I2C lcd(0x3F, 16, 2);  //Define LCD type.

//Variables
float voltage, degreesC, degreesF;

void setup() {
  Serial.begin(9600);
  lcd.init();  // initializing the lcd
  lcd.backlight();
  lcd.setBacklight(HIGH);
}

//This is void setup, set the baud rate firstly. Then initialize the LCD and backlight.Then enter into void loop

void loop() {

  voltage = getVoltage(TMP36);

  // Now we'll convert the voltage to degrees Celsius.
  // This formula comes from the temperature sensor datasheet:

  degreesC = (voltage - 0.5) * 100.0;

  // While we're at it, let's convert degrees Celsius to Fahrenheit.
  // This is the classic C to F conversion formula:

  degreesF = degreesC * (9.0 / 5.0) + 32.0;

  Serial.print("  deg C: ");
  Serial.println(degreesC);
  // Serial.print("  deg F: ");
  // Serial.println(degreesF);

  lcd.setCursor(0, 0);
  lcd.print("Temperature: ");
  lcd.print(degreesC);
  lcd.print((char)0xDF);
  lcd.print("C");

  if (degreesC > 24) {
    digitalWrite(Relay, HIGH);  // Turn the fan on
    lcd.setCursor(0, 1);
    lcd.print("Fan: ");
    lcd.print("On");
  } else {
    digitalWrite(Relay, LOW);  // Turn the fan off
    lcd.setCursor(0, 1);
    lcd.print("Fan: ");
    lcd.print("Off");
  }

  delay(3000);  // repeat once per 3min (change as you wish!)

  //Set the cursor for Temperature printing on LCD and print it on 2nd row and from 1st column. Here, ‘lcd.print((char)0xDF);’ used to print Degree on the LCD.

  lcd.clear();

  //Delay for 3 second and clear the whole LCD

  lcd.setCursor(0, 0);
  lcd.print("www.EEmentor.co");
  delay(2000);
  lcd.clear();
}

float getVoltage(int pin) {
  return (analogRead(pin) * 0.004882814);
}