Temperature Controlled Fan

[azx1209]

Hi! Im new here and I'm not really sure how to use this site yet, although I have a question that I hope someone can answer right away!

So I have this project in my school and I only based this of a youtube video and his works perfectly, https://youtu.be/eg8AlYlV0PM?feature=shared

However, instead of a 5v fan I used a 12v dc fan. I also am not so sure how high the resistance is for the potentiometer and used a 50k one

THE PROBLEM : After I plug every wiring, and input the coding needed, my lcd should say "Temp : (the number) C ", but instead it says "Temp: nanC". When I searched it, it said "Not a number" so I am not sure what that means. Another problem is when the fan turns on always, and the speed doesnt really change so I'm gonna need help with that also. I also need help with the potentiometer. Is there something wrong with the code?

here's the wirings

and here's the code

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

#define DHTPIN 2
#define DHTTYPE DHT11

DHT dht(DHTPIN, DHTTYPE);

const int potPin = A0;
const int fanPin = 3; // Connect the fan to this pin

LiquidCrystal_I2C lcd(0x27, 16, 2); // Set the LCD address and dimensions

void setup() {
  dht.begin();
  pinMode(fanPin, OUTPUT);
  lcd.init();                      // Initialize the LCD
  lcd.backlight();                 // Turn on the backlight
  lcd.setCursor(0, 0);
  lcd.print("Temp Fan Control");
  lcd.setCursor(0, 1);
  lcd.print("by Your Name");
  delay(2000);
  lcd.clear();
}

void loop() {
  int threshold = map(analogRead(potPin), 0, 1023, 20, 40); // Map potentiometer value to temperature range

  float temperature = dht.readTemperature();

  if (temperature > threshold) {
    digitalWrite(fanPin, HIGH); // Turn on the fan
  } else {
    digitalWrite(fanPin, LOW); // Turn off the fan
  }

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Temp: ");
  lcd.print(temperature);
  lcd.print("C");

  lcd.setCursor(0, 1);
  lcd.print("Threshold: ");
  lcd.print(threshold);
  lcd.print("C");

  delay(1000);
}

[ruilviana]

nan means que o numero lido não é valido : Not A Number.
No seu projeto Istto é causado porque não está conseguindo cessar o DHT11.
Reveja as ligações do seuu DHT11 ou até o substitua.

[jim-p]

@azx1209

and his works perfectly,

At least untill the Uno burns out from drawing to much current.
You will need a separate 12V power supply for the fan and a relay or transistor to drive it.

[PaulRB]

@azx1209

here's the wirings

Don't follow those wirings. They will damage the Arduino.

@azx1209

and here's the code

Based on the wirings, I suggest the Youtuber is of a similar level of knowledge and experience as yourself, so I would not trust that the code is correct.

Begin by connecting only the sensor and the Arduino and try the example sketch from the DHT library.

[ruilviana]

I tested your code in the simulator.
The code worked correctly, showing the temperature value.

Follow the instructions on powering your project

and check the connections of your sensor or replace it.