Temperature Controlled Fan Speed System using AT89S52

This embedded system automatically controls a DC fan based on ambient temperature using the AT89S52 microcontroller, ADC0804, and LM35 temperature sensor.
When the temperature exceeds 29°C, the fan turns ON automatically; otherwise, it remains OFF.

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🧩 Components Used

• AT89S52 microcontroller
• ADC0804 (Analog to Digital Converter)
• LM35 temperature sensor
• 16x2 LCD display
• BC547 transistor (fan driver)
• DC fan, resistors, capacitors, and 10k potentiometer

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🧰 Tools Used

• Keil µVision IDE – for Embedded C code
• Proteus Design Suite – for circuit simulation and testing

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⚙️ Circuit Diagrams

When Temperature > Threshold (Fan ON):

When Temperature < Threshold (Fan OFF):

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💡 Working Principle

1. LM35 senses ambient temperature and outputs an analog voltage.
2. ADC0804 converts the analog voltage into a digital signal.
3. AT89S52 processes the data and determines whether to activate the fan.
4. Temperature and fan status are displayed on the LCD.

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📜 License

This project is licensed under the MIT License. See the LICENSE file for more details.

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👨‍💻 Author

Sreyas Kishore