Project Hub /Basic Analog & Power Electronics/Sequential, Timing & Pulse Circuits/Street Light Controller Circuit with Effective Switching

Beginner

ANALOG / DISCRETE

< ₹500

3 – 6 Hours

Partial Kit

Street Light Controller Circuit with Effective Switching

Learn how to build an automated street light controller circuit using op-amp IC 741 and CD4060 to efficiently control street lights and prevent false triggering.

Originally published on ElectronicsForU

View original tutorial

Parts You'll Need

This project is sourced from another site, not written by us — this list is our best match of their components against what we stock, not a verified bill of materials. Always check the original blog (linked above) for the actual parts list before buying.

LDR Light Sensor Module Rs. 49.00
5V 1 Channel Relay Module Rs. 45.00
10pcs - 220 ohm 1/4 W Resistor Set Rs. 39.00
MB102 Adjustable Breadboard Power Supply Module (3.3V & 5V) for Arduino & Raspberry Pi Rs. 139.00
400 Points Mini Solderless Prototype PCB Breadboard High Quality Rs. 89.00
Jumper Wire 10 Pin Male To Male 20cm Rs. 45.00
Jumper Wire 10 Pin Male To Female 20cm Rs. 45.00

Selected: Rs. 0.00

This list includes a generic resistor set as a placeholder — it is not matched to the exact value or part number this circuit needs. The correct one is specified on the original source page linked above; check it before buying.

We don't carry yet: Op-Amp IC (LM358 / LM741 / TL072)
Logic ICs (74xx / 40xx)
Thyristor / SCR / Triac / Varistor / Fuse
Transistors (BC547 / 2N2222 / TIP / MOSFET)
Diodes (1N4007 / 1N4148 / Schottky / Zener)
Perfboard / Veroboard / Stripboard

Browse all components

How It Works

The Street Light Controller Circuit operates by combining ambient light sensing with precise timing control to automate outdoor illumination. At the heart of the light-sensing section is an LDR 1 (Light Dependent Resistor) working alongside a preset resistor (VR2) and an Op-Amp IC 741 (IC1). As evening approaches and ambient light levels drop, the resistance of LDR 1 increases, causing the voltage at the input of the Op-Amp to cross a specific threshold. This causes the IC 741 to change its output state, signaling dusk. To prevent the system from reacting to brief flashes of light like passing car headlights—which causes false triggering—the signal is routed into a 14-bit ripple counter CD4060 (IC2). The CD4060 acts as a stabilizing time delay counter, ensuring that darkness persists for a sustained period before any switching action occurs. Once the counter confirms the dusk condition, it activates a BC557 PNP transistor and a secondary transistor (T2) stage. These transistors amplify the control signal sufficiently to trigger an SCR BT169 (Silicon Controlled Rectifier). The SCR then energizes a Relay (RL1), which acts as an electromagnetic switch to close the high-power circuit connected to the street light. Diodes like D3 are included for flyback protection against voltage spikes when the relay coil switches. Power is delivered to the entire control board via a steady regulated 12V DC power supply, built neatly on a general-purpose PCB.

Why Build This

Gain practical hands-on experience designing automated dusk-to-dawn lighting systems for municipal or residential applications.

Learn how to integrate analog sensors with digital timing counters to prevent false triggering from transient light sources.

Understand how low-voltage control circuits safely interface with relays to switch higher-power AC electrical loads.

Real-World Application

Automated street lighting systems for municipal or residential applications, ensuring energy efficiency and accurate dusk-to-dawn operation without false triggers.

Skills You'll Learn

Op-amp threshold detection

digital ripple counter operation

transistor biasing and switching

SCR triggering circuits

relay interfacing

analog sensor signal conditioning

Safety Precautions

Exercise caution when working with mains AC voltage connected to the relay terminals.

Technology Tags

OP-AMP IC 741

CD4060

SCR BT169

LDR

RELAY

TRANSISTOR

ANALOG ELECTRONICS

TIMING CIRCUIT

Frequently Asked Questions

Why is an Op-Amp IC 741 used along with a CD4060 counter instead of just the LDR alone?

Using just an LDR can cause the street light to flicker or turn on prematurely if a temporary shadow passes over it. The IC 741 detects the initial light threshold, while the CD4060 counter adds a necessary time delay to confirm that darkness is permanent before switching the light on.

What is the role of the SCR BT169 and Relay (RL1) in this circuit?

The low-voltage control signals from the ICs cannot directly power a heavy-duty street light. The transistor stage triggers the SCR BT169, which in turn energizes the Relay (RL1). The relay provides electrical isolation, acting as a heavy-duty switch for the mains-powered lighting load.

Do I need any microcontroller programming or software to build this project?

No, this is a purely hardware-based analog and digital logic project. No software writing, flashing, or compilation is required.

Gallery

This page is part of Kitkraft's Project Hub — a curated collection of electronics & robotics projects gathered from the maker community to help students and hobbyists discover and learn to build. Kitkraft does not claim authorship of the original project, and makes no representation as to the accuracy, completeness or safety of third-party source material. The summary and "How It Works" explanation above are AI-generated, rewritten with reference to the original tutorial — not a reproduction of it. Full credit and a direct link to the original source are provided above. If you're the original creator and have a concern about how your work is represented here, please contact us and we'll address it promptly.

Kitkraft Project Hub — curated from the maker community, credited at the source.

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