Project Perspective

Energy Efficient Light Bulb is a fundamental and practical energy-saving project for anyone to understand about basic physical and digital interaction. By using a motion sensor and their relay feedback, you'll learn about home automation and energy management.

Technical Implementation: Sensors and Relays

The project focuses on creating a high-performance and reliable energy-saving light:

• Sensing layer: Using a PIR Motion Sensor (HC-SR501), the Arduino can accurately detect human movement within a specific range (up to 7 meters).
• Control Interface layer: When motion is detected, the Arduino triggers a 5V Relay Module, which acts as an electronic switch to turn on the high-voltage light bulb.
• Timing Logic layer: The Arduino code includes a timer to keep the light on for a pre-set duration (e.g., 30 seconds) after the last motion is detected, ensuring it doesn't turn off too quickly.

Hardware Infrastructure

• Arduino Uno: The "brain" of the project, managing the motion sensor and coordinating relay activities for the light bulb.
• HC-SR501 PIR Motion Sensor: Providing contactless motion detection by measuring infrared radiation changes in the surrounding environment.
• 5V Relay Module: Effectively isolates and controls high-voltage/current light bulbs with a low-voltage signal.
• Micro-USB Cable: Use to program the Arduino directly from your computer for power and code.
• Jumper Wires: Connect all the components together.

Detection and Execution Loop

The energy-efficient light bulb is designed to be very efficient:

1. Initialize Sensor: SETUP the PIR motion sensor to its default sensitivity and time settings.
2. Poll Motion: The Arduino constantly measurements the PIR sensor's output to check for human movement.
3. Relay Trigger: If motion is detected, the Arduino sends a HIGH signal to the relay, turning on the AC light bulb.
4. Time Out Logic: After motion stops, the Arduino waits for several seconds before sending a LOW signal to the relay, ensuring the light only stays on when its needed.

Future Expansion

• LDR Light Level Integration: Add a photoresistor (LDR) to ensure the light only turns on when motion is detected and its dark outside.
• Cloud Status Sink: Add a WiFi module (ESP8266/ESP32) to log each time the light is activated into a cloud dashboard for energy usage tracking.
• Dimmable LED Bulb Integration: Use an AC dimmer module to create and manage several levels of brightness based on the time of day.
• Custom Pulse Alert Support: Add a small buzzer to give a final "time's up" audio alert before the light turns off.

Energy Efficient Light Bulb is a perfect project for any electronics enthusiast looking for a more interactive and engaging energy-saving tool!