Automatic Street Lighting System with Dimming - Electrical Engineering Guide
1. Introduction
The Automatic Street Lighting System with Dimming is designed to optimize energy usage by controlling street lights based on ambient light levels and time. The system dims lights during low-traffic hours, reducing power consumption and extending lamp life.
2. Objectives
• Automate street lighting based on natural light and time.
• Incorporate dimming control for low-traffic periods.
• Improve energy efficiency and reduce electricity costs.
• Ensure safety and proper illumination during critical hours.
3. Components Required
• LDR (Light Dependent Resistor) or Ambient Light Sensor
• Microcontroller (Arduino/ESP32)
• Real-Time Clock (RTC) Module
• TRIAC/MOSFET for power control
• Opto-isolators
• LEDs or Street Light Bulbs
• Power Supply Unit (12V or 5V)
• Resistors, Capacitors, and PCBs
• Wires, Enclosure, and Mounting Hardware
4. System Architecture
The system consists of a light sensor, microcontroller, RTC module, dimming controller (PWM/phase control), and street lighting units. It detects ambient light and time to adjust light brightness accordingly.
5. Working Principle
During the day, the light sensor detects sufficient natural light and turns the street lights off. At dusk, lights are turned on and dimmed during late-night hours. Brightness is adjusted using PWM or phase-cut dimming depending on the lamp type.
6. Circuit Design and Operation
• Use voltage dividers with LDR to read light levels.
• Interface RTC to track time and enable dimming logic.
• Control high-power lamps using TRIAC/MOSFET through opto-isolators.
• Ensure stable power regulation to all components.
7. Light Sensor Integration
• Connect LDR to analog input with a pull-down resistor.
• Calibrate threshold values for day/night detection.
• Optional: Use TSL2561 or BH1750 for digital light measurement.
8. Microcontroller Configuration
• Program Arduino to read sensor data and RTC.
• Use digital output pins to control dimmer circuits.
• Implement logic to determine light on/off and brightness levels.
9. Dimming Control Mechanism
• For LED: Use PWM to control brightness.
• For AC lamps: Use phase-cut dimming with TRIAC.
• Adjust dimming level based on time (e.g., 100% from 6–10 PM, 50% from 10 PM–5
AM).
10. Power Supply Design
• Use regulated power supply (e.g., 12V to 5V converter).
• Ensure proper current rating for driving relays and control units.
• Isolate control and load circuits for safety.
11. Safety and Protection
• Include fuses, varistors, and surge protectors.
• Use opto-isolators for high-voltage control.
• Protect against short circuits and overcurrent conditions.
12. Software and Firmware
• Write firmware in Arduino IDE or C/C++.
• Include libraries for RTC and PWM control.
• Implement scheduling and brightness adjustment logic.
13. Assembly and Installation
• Assemble circuit on PCB or breadboard.
• Mount sensors at appropriate height.
• Install weatherproof enclosure for outdoor use.
• Connect lighting load securely.
14. Testing and Calibration
• Test sensor readings under different lighting conditions.
• Verify dimming behavior across time intervals.
• Calibrate PWM values to match desired brightness.
15. Applications
• Urban and rural street lighting
• Campus and park lighting
• Smart city infrastructure
• Energy conservation projects
16. Future Enhancements
• Integration with IoT for remote monitoring
• Motion sensors for adaptive lighting
• Solar power integration
• AI-based traffic pattern prediction for smart dimming
17. Conclusion
This project demonstrates an efficient and intelligent street lighting system that reduces energy consumption through automatic operation and dimming. It is scalable, cost-effective, and contributes to sustainable infrastructure development.