FYP 2 Week 9

Alhamdulillah, now I finally found the code that works for my circuit. It works beautifully as I have expected. Here is the code:

#include <LiquidCrystal.h>

int pin = 0;                // analog pin

int tempc = 0,tempf=0;      // temperature variables

int samples[8];             // variables to make a better precision

int maxi = -100,mini = 100; // to start max/min temperature

int i;

int TIP122pin = 9;

int fanspeed = 0;

int fanStemp = 0;

LiquidCrystal lcd(12, 11, 5, 4, 3, 2); // Customize for your connections.

void setup()

{

  Serial.begin(9600);       // start serial communication

  lcd.begin(16,2);          // set up the LCD's number of columns and rows

  pinMode(TIP122pin, OUTPUT); // Set pin for output to control TIP122 Base pin

  analogWrite(TIP122pin, 255); // control the fan speed by changing values from 0 to 255

  delay(200);

}

void loop()

{

  

tempc = 0;

for(i = 0;i<=7;i++){         // gets 8 samples of temperature

  samples[i] = ( 5.0 * analogRead(pin) * 100.0 ) / 1024.0;

  tempc = tempc + samples[i];

  delay(1000);

}

tempc = tempc/8;               // better precision

tempf = (tempc * 9)/ 5 + 32;     // converts to fahrenheit

if(tempc > maxi) {maxi = tempc;} // set max temperature

if(tempc < mini) {mini = tempc;} // set min temperature

 if ( tempc > 24 && tempc < 37 ) {

    fanStemp = tempc + 50;

    fanspeed = fanStemp + 100;

    analogWrite(9,fanspeed);

    Serial.print("Fan started at temp+50+100 speed\n");

    Serial.print(fanspeed,DEC);

    Serial.print("\n");

    delay(100);

  }

    else if ( tempc <= 24 ) {

    fanspeed = 0;

    analogWrite(9,fanspeed);

    Serial.print("Fan off\n");

    delay(100);

   }

   else{

     analogWrite(9,255);

     Serial.print("Fan started at full speed\n");

     delay(100);

   }

   

Serial.print(tempc,DEC); // serial print for debugging all serial.print commands

Serial.print(" Celsius, ");

Serial.print(tempf,DEC);

Serial.print(" fahrenheit -> ");

Serial.print(maxi,DEC);

Serial.print(" Max, ");

Serial.print(mini,DEC);

Serial.println(" Min");

lcd.setCursor(0, 0);  // set the cursor to (0,0)

lcd.print(tempc,DEC);  // print temp in C and F on the first row of the lcd

lcd.print(" C, ");

lcd.print(tempf,DEC);

lcd.print(" F");

lcd.setCursor(0, 1);  // set the cursor to (16,1)

lcd.print(maxi,DEC);   // Print max temp and min temp on the second row of lcd

lcd.print("  Max, ");

lcd.print(mini,DEC);

lcd.println(" Min.");

delay(1000);                   // delay before loop

}

These are the pictures of the constructed circuit on the breadboard:

The circuit before being plugged with power supply.

The circuit with the power supply, you can see the fan is moving and the LCD display is showing the temperature.