🔥 Automatic Air Control System using PIC18F45K22

An embedded system that intelligently monitors and controls air temperature using the PIC18F45K22 microcontroller. The system compares user-defined temperature input with real-time sensor readings to activate either a heater or a fan, ensuring optimal environmental conditions.

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🖼️ System Circuit Diagram

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📌 Project Overview

This project allows users to set a reference temperature through a keypad. Based on this reference, the system continuously reads ambient temperature using an LM35 sensor. It reacts accordingly:

• If the actual temperature is lower than desired → it activates the heater.
• If it's higher → it turns on the fan.
• If it's equal → both remain off.

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🧠 System Features

• Real-time temperature monitoring.
• Automatic switching between heating and cooling.
• User-defined temperature input.
• Visual feedback via LCD screen.
• Warnings for extreme temperatures.

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🧰 Hardware Components

Component	Description
PIC18F45K22	Main microcontroller
LM35	Analog temperature sensor
16x2 LCD	Displays values and system status
4x4 Keypad	User input for reference temp
Fan + Relay	Cooling system
Heater + Relay	Heating system
Transistors	Switching control for relays
Power Supply	5V regulated

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🔁 System Logic Flow

1. Startup screen → "Welcome to Temperature System"
2. User Input → Set desired temperature via keypad.
3. Comparison → Actual vs. Reference.
4. Control:
   • Turn ON heater if too cold.
   • Turn ON fan if too hot.
   • Turn both OFF if stable.
5. Alerts:
   • Displays "So Hot" or "So Cold" for critical cases.

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⚙️ How Temperature is Calculated

temp = ADC_Read(0);                  // Read analog voltage
mV = temp * 5000.0 / 1024.0;         // Convert to mV
ActualTemp = mV / 10.0;              // LM35 = 10mV/°C

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💻 Software Tools

• MPLAB X / MikroC – For code development.
• Proteus 8 – For circuit simulation and testing.
• Pickit3 – For programming the microcontroller.

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📦 Repository Contents

File	Description
AutomaticControlSystem.c	Main embedded C code
file_2025-05-02_09.35.42.png	System diagram screenshot (Proteus)
README.md	Project documentation

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👥 Contributors

Special thanks to the project team:

• Hedra-Nabil
• [nagham959](https://github.com/nagham959)

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🚀 Future Improvements

• Add buzzer alert for critical temp conditions.
• Interface with Bluetooth for mobile control.
• Store last-used temperature in EEPROM.
• Replace LCD with OLED for better visuals.
• Implement automatic fan speed control using PWM.

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📄 License

This project is open-source and free for educational and personal use.

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💬 Contact

For feedback or collaboration:

• GitHub: github.com/Hedra-Nabil