Page 78 - RASAS 2025

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10 Ruhuna Arts Student’s Annual Sessions (RASAS) -2025

Design and Implementation of an IoT-Based Smart Streetlight System with LDR
Sensor for Energy Efficiency and Adaptive Lighting Control

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M.S.T.C. Ihalage* , S.M.B.N. Weeragala , R.A.S.P. Rajasingha , P.K.G. Maduranga 4
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Department of Information Technology, University of Ruhuna
thakshilaihalage@gmail.com

ABSTRACT

A traditional streetlight system is a basic outdoor lighting design widely used to illuminate roads and public
spaces, often leading to unnecessary energy consumption. To overcome this limitation, an IoT-based smart
streetlight system enhances energy efficiency and adaptive lighting control, especially in commercial

environments. The main objective of the project is to design and implement an IoT-based smart streetlight
system that can automatically manage lighting based on ambient light levels, reduce electricity usage, and
minimize human effort in controlling streetlights. The prototype is developed using an Arduino UNO

microcontroller, a Light Dependent Resistor (LDR) sensor, BC547 transistors, torch bulbs, resistors, and
jumper wires to enable automatic and user-friendly lighting control. The LDR sensor detects the light intensity
level, and the system automatically turns on the lights when low light is detected (e.g., at night) and turn them

off when there is sufficient daylight. The software implementation is done through the Arduino IDE using the
C++ programming language. The functional process of the system is represented through a Data Flow Diagram

(DFD), which illustrates the interaction between the sensor, microcontroller, and lighting units for automated
decision-making. Findings from existing IoT-based smart lighting research demonstrate that such systems can
achieve approximately 50–60% reductions in electricity consumption with 2-3s response time, significantly

lowering operational costs, improving energy efficiency. and preventing unnecessary operation of lights during
daylight hours. The novelty of this project is a low-cost, scalable design adaptable for both rural and

commercial environments, while also reducing human intervention. The project is useful for providing services
by minimizing electricity consumption in both urban and rural areas. Since the process cannot be performed
manually due to human busyness, the project is designed to automatically turn on the lights when the brightness
decreases and automatically turn them off when the brightness increases. Further real-world testing and

exploration of integration with renewable energy sources, such as solar power, are recommended to further
enhance sustainability.

Keywords: Adaptive Streetlighting Control, Arduino-Based Automation, IoT-Based Street Lighting, Light
Dependent Resistor (LDR) Sensor, Smart Streetlight System

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