Multi-colour Night Light Circuit Using CD4017

Are you looking for a DIY automatic night lamp circuit that is simple, power-efficient, and colorful? 🌙💡 If yes, then this project is perfect for both beginners and electronics enthusiasts. It allows you to create a multi-colour LED night lamp using an LDR (Light Dependent Resistor), the CD4017 decade counter, and the NE555 timer IC.

Night lamps are extremely useful because they provide gentle lighting without disturbing sleep 😴. Moreover, they help prevent tripping on stairs 🚶‍♂️, make children feel safe, and can even serve as an emergency guide light during power cuts. In addition, this circuit offers five beautiful LED colours – 🔴 Red, 🟢 Green, 🔵 Blue, 🟡 Yellow, and ⚪ White – which you can select using a simple push button switch. Best of all, it automatically turns ON when the room becomes dark 🌌, and therefore ensures both safety and convenience.

🛠️ Parts Required for Multi-Colour Night Light

Resistors (All 1/4W)

• R1 – 330Ω
• R2 – 1MΩ (Preset)
• R3 – 33KΩ
• R4, R7 – 10KΩ
• R5 – 100KΩ
• R6 – 4.7KΩ / 5KΩ (Potentiometer for brightness control)

Capacitors

• C1 – 22µF / 25V
• C2 – 100µF / 25V

LEDs (3mm/5mm/8mm)

• L1 – White ⚪
• L2 – Yellow 🟡
• L3 – Green 🟢
• L4 – Blue 🔵
• L5 – Red 🔴

Other Components

• Q1 – BC547 (NPN Transistor)
• Q2 – 8050 or 2N2222 (NPN Transistor)
• U1 – CD4017 Decade Counter IC
• U2 – NE555 Timer IC
• LDR (Light Dependent Resistor)
• S1 – Momentary Switch (Push-to-ON)
• DB – DB107 Bridge Rectifier
• PS – 12V Power Supply / Adapter
• General Purpose PCB

⚡ How the Automatic Night Light Circuit Works

👉 Light Detection: The LDR senses ambient light. When the room light goes OFF, the lamp circuit turns ON automatically.

👉 Colour Selection: A momentary switch (S1) is used to select your favorite LED colour. Each press cycles through the five outputs of the CD4017 IC, changing the colour of the lamp. 🌈

👉 Brightness Control: The R6 potentiometer allows you to adjust the brightness of the LEDs. Perfect for a soft glow or a brighter effect.

👉 Sensitivity Adjustment: The R2 preset helps set the light sensitivity of the LDR. You can fine-tune it to decide when the lamp should turn ON.

👉 Power Efficiency: The circuit consumes very low power and can run on a regulated 12V DC adapter or a small inbuilt power supply. 🔋

⭐ Key Features of the Multi-Colour Night Light Circuit

✅ Automatically turns ON in the dark 🌙
✅ Five different LED colours (Red, Green, Blue, Yellow, White) 🌈
✅ Adjustable brightness & sensitivity ⚙️
✅ Low power consumption 🔋
✅ Works with a simple 12V power supply ⚡

📌 Applications

• Bedroom Night Lamp 🛏️
• Kids’ Room Decorative Lamp 🎨
• Emergency Exit Indicator 🚪
• Stairway / Hallway Safety Light 🪜
• DIY Electronics Learning Project 👨‍🔧

This multi-colour automatic night light circuit using LDR, NE555, and CD4017 is simple to build yet highly practical. Not only does it save energy, but it also adds a touch of colour to your room 🌟. With adjustable brightness and automatic ON/OFF, it’s a perfect blend of functionality and creativity.

👉 Try building this project on a general-purpose PCB, and you’ll have a reliable and fun DIY night lamp ready in no time!