🔆 Automatic Room Lighting System

Date: October 30, 2021

Purpose: Energy conservation through automation using IR sensors and a microcontroller.

🔰 Introduction

Electricity is an indispensable part of modern life. However, with rising energy demands and depleting non-renewable resources, energy conservation has become a necessity. One major area where energy is often wasted is lighting—many people forget to switch off lights when leaving a room.

To address this, we’ve designed an Automatic Room Lighting System, which uses IR sensors and a microcontroller (ATmega32) to automatically switch lights ON or OFF based on room occupancy. This system not only helps reduce electricity bills but also promotes responsible energy usage.

🧠 Working Principle

Entry: Sensor 1 → Sensor 2 → Light ON + Counter++

Exit: Sensor 2 → Sensor 1 → Counter-- → Light OFF if Count = 0

This project is based on a bi-directional human detection mechanism using two IR sensors positioned at the entrance of a room. Here's how it works:

➕ When a person ENTERS the room:

• Sensor 1 (outside) is triggered first, followed by Sensor 2 (inside).
• This sequence tells the microcontroller to turn ON the lights/fans and increment the visitor count.

➖ When a person LEAVES the room:

• Sensor 2 (inside) is triggered first, followed by Sensor 1 (outside).
• The microcontroller decrements the visitor count. If count = 0, it turns OFF the lights/fans.

🧾 Components Required

#	Component	Quantity
1	ATmega32 Microcontroller	1
2	16 MHz Crystal Oscillator	1
3	IR Sensor Modules	2
4	0.1µF Ceramic Capacitors	10
5	18pF Ceramic Capacitors	4
6	10kΩ Resistors	10
7	330Ω Resistors	10
8	Red LEDs	6
9	Green LEDs	10
10	Seven-Segment Displays	2
11	Breadboard	1
12	Connecting Wires (5m)	As needed

Key Points:

• IR sensors are placed on either side of the door.
• The microcontroller processes IR input and controls relays for AC appliances.
• 7-segment display shows the live visitor count.

(Insert or link to your circuit diagram image here)

⚙️ Procedure

1. Place Sensor 1 outside and Sensor 2 inside the room entrance.
2. Program ATmega32 to monitor IR sensor inputs and update person count.
3. Use a relay driver to switch lights/fan based on count.
4. Display the visitor count on a 7-segment display.

✅ Output

• System automatically manages room lighting based on human presence.
• Visitor counter works accurately with multiple entries/exits.
• Lights stay ON as long as there's at least one person inside.
• Reduces power wastage and enables smart automation.

📝 Conclusion

This project combines IR sensing and microcontroller logic to automate room lighting. It’s useful for homes, classrooms, offices, and more, helping reduce electricity consumption and human error.

• Prevents energy wastage
• Accurate room occupancy detection
• Scalable and simple to implement
• Ideal for smart buildings and IoT automation

💡 Future Scope

• Integrate with IoT platforms for remote monitoring
• Use PIR sensors for better accuracy
• Support temperature/humidity-based fan control
• Add mobile app control via WiFi modules

Do you want the code, circuit file, or Proteus simulation? Let me know in the comments and I’ll share the files!