Project Hub /IoT & Connected Devices/Smart Home & Building Automation/Washbasin Mirror Light Controller

Intermediate

ANALOG / DISCRETE

₹500 – ₹1,500

3 – 6 Hours

Partial Kit

Washbasin Mirror Light Controller

An automated and manual control circuit for washbasin mirror lights using an IR object sensor to save power by turning off lights when not in use.

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.

5V 1 Channel Relay Module Rs. 45.00
2-Slot 18650 Holder with Protective Cover and On/Off Switch – Case Rs. 109.00
10pcs - 220 ohm 1/4 W Resistor Set Rs. 39.00
10pcs 5mm RED Diffused Light Emitting Diodes - LEDs Set Rs. 39.00
400 Points Mini Solderless Prototype PCB Breadboard High Quality Rs. 89.00
MB102 Adjustable Breadboard Power Supply Module (3.3V & 5V) for Arduino & Raspberry Pi Rs. 139.00
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: Diodes (1N4007 / 1N4148 / Schottky / Zener)
Voltage Regulator IC (7805 / LM317 / 1117)
LM35 / Analog Temp Sensor
555 Timer IC
Transistors (BC547 / 2N2222 / TIP / MOSFET)
Capacitors
Potentiometer / Trimpot
Custom PCB / PCB Fab
Sharp 2Y0A21 infrared object sensor
connecting components

Browse all components

How It Works

The Washbasin Mirror Light Controller is an automated and manual power-switching circuit built using discrete analog and power electronics components. Power is supplied to the system via a bridge rectifier (BR1) and stepped down cleanly by a 5V voltage regulator (7805, IC1) to power the control logic. The system relies on a Sharp 2Y0A21 infrared object sensor to detect a user standing in front of the washbasin mirror. When the IR sensor detects an object, it sends an analog signal to an LM358 operational amplifier (IC2), which acts as a comparator to process the threshold voltage set by the voltage-divider potentiometer (VR1). Once triggered, the signal passes to an NE555 timer (IC3) configured to manage the precise timing interval determined by timing capacitor C4 and resistor R4. The output from the timer drives a pair of BC548 transistors (T1 and T2) connected in a configuration capable of supplying sufficient current to actuate the 12V single-changeover relay (RL1). The relay physically switches the power circuit connected to the light bulb (B1). Additionally, manual switches S1 and S2 allow users to override the automated IR sensor functionality, giving direct control over the mirror lighting when needed.

Why Build This

Design an automated power management system for residential or public restrooms to significantly reduce standby energy waste.

Gain practical undergraduate-level experience integrating analog sensors, operational amplifiers, and timer ICs with electromechanical relays.

Implement a hybrid control scheme that successfully combines automated proximity sensing with manual override switching.

Real-World Application

Energy conservation in residential, commercial, or public restrooms by automatically controlling mirror and vanity lights based on user presence.

Skills You'll Learn

Analog sensor integration

Op-amp threshold detection

555 timer circuit design

Transistor switching stages

Relay control interfacing

AC-DC power supply regulation

Safety Precautions

Exercise caution when working with 230V AC mains electricity connected to the relay and circuit input. Ensure proper insulation and enclosure mounting to avoid electric shock.

Technology Tags

IR SENSOR

SHARP 2Y0A21

LM358

NE555 TIMER

RELAY

POWER SUPPLY

PCB DESIGN

COMPARATOR

MONOSTABLE MULTIVIBRATOR

Frequently Asked Questions

Can I use this circuit with a 240V AC light bulb?

Yes, provided the 12V single-changeover relay (RL1) used is properly rated to handle the switching voltage and current loads of your specific AC mains bulb.

What is the purpose of the 7805 voltage regulator?

The 7805 IC ensures that the sensitive control logic, op-amp, and timer components receive a stable, constant 5V DC supply, protecting them from voltage fluctuations.

How do switches S1 and S2 affect the automated sensor?

The manual switches provide an override function, allowing you to turn the light bulb on or off independently of whether the Sharp IR sensor detects a user.

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.

PRJ-00329