LDR (Light Dependent Resistor) is a special type of resistor that works on the photoconductivity principle means that resistance changes according to the intensity of light.
The details about LDRs and their fundamentals are discussed in this article on What is LDR?
There are many Electronics projects which use LDRs as their main driver of the circuit. In the list below, we list the top 10 Electronics Projects which are based on these LDRs.
Automatic Curtain Operation Using LDR
It does the task of folding and unfolding the curtain as per the light intensity outside the window. It is an automatic process and the light intensity is sensed by LDR in the circuit.
You can read the full project here: Automatic Curtain Operation Using LDR
LDR Plus GSM Based Security System
This project will teach us how to make a smart device that can notify us whenever any unauthorized person opens the safe box/drawer.
You can read the full project here: LDR Plus GSM Based Security System
LDR-Based DC Motor Speed Control
A light-dependent resistor (LDR) whose resistance is inversely proportional to the intensity of light is often used as a sensor in electronic projects that involve the use of light. This LDR-based DC motor speed control project uses an LDR to control the speed of a DC motor.
You can read the full project here: LDR Based DC Motor Speed Control
How to Play With Light Using LDR
Smart bulb holder is an incandescent, compact fluorescent or LED light bulb holder with a simple dusk-to-dawn/twilight controller circuit
You can read the full project here: How to Play With Light Using LDR
Light Operated Doorbell
Here is a simple light-operated switch that you can affix to the main door of your house to work as an automatic doorbell or a thief alarm.
You can read the full project here: Light Operated Doorbell
Fan on/off Control by Light
This circuit lets you turn on/off a fan by just directing torchlight or other light toward its light-dependent resistor (LDR). The circuit is powered from a 5V power supply.
You can read the full project here: Fan on/off Control by Light
LED As Light Sensor
A simple circuit construction that uses a transparent red LED as the light sensor that switches on a white LED when the red LED is in dark.
You can read the full project here: LED As Light Sensor
Light Operated Internal Door Latch
Using this light-operated door latch circuit, you can close or open the door of your room remotely from your bed. You just have to focus the torchlight on the light-dependent resistor of the circuit, which you can install inside your room at a suitable position.
You can read the full project here: Light Operated Internal Door Latch
This door guard uses an operational amplifier µA741 and a light-dependent resistor (LDR). Operational amplifier µA741 is used as a sensitive voltage comparator.
You can read the full project here: Door Guard
Automatic Night Lamp With Morning Alarm
This automatic night lamp circuit turns on a night lamp when bedroom light is switched off. The lamp remains ‘on’ until the light sensor senses daylight in the morning.
You can read the full project here: Automatic Night Lamp With Morning Alarm