LDR Sensor With Arduino
LDR Sensor With Arduino Nano To On/Off Light Project –Light Detection Made Simple! Have you ever wondered how street lights automatically turn on when it gets dark? Or how some solar lamps know when to light up at night? The magic behind that is a tiny but clever component called an LDR, and in this blog, we’ll learn how to use it with the Arduino Nano to build your own light-detecting system!
Table of Contents
What is an LDR? (Explained Simply)
An LDR, or Light Dependent Resistor, is a small electronic part that can “see” how bright or dark it is around it.
Imagine it like a tiny electronic eye that reacts to light:
- When there’s lots of light (like sunlight or a lamp), the LDR allows electricity to flow through it easily.
- When it’s dark, it makes it harder for electricity to pass through.
So, an LDR changes its resistance depending on the amount of light it receives. That’s why it’s also called a photoresistor.
Standard LDR Size
These are the most common LDRs you’ll find in DIY and educational projects. They usually come in the form of small cylindrical components with two metal leads for connecting to a circuit.
Physical Dimensions:
- Diameter: Around 5-8 mm (0.2-0.3 inches)
- Length: Typically between 20-30 mm (0.8-1.2 inches)
What Is Arduino Nano:
Click Here To See Also: Arduino Nano Discription:Arduino Nano Projects
Project: Light Sensing (On/Off Led) Using LDR Sensor With Arduino Nano:
Objective:
To detect light intensity using an LDR and control an output (like an LED, buzzer) based on the brightness of the environment
Components Required:
- 1 × Arduino Nano
- 1 × LDR (Light Dependent Resistor)
- 1 × 8kΩ resistor (for voltage divider)
- 1 × LED
- 1 × 220Ω resistor (for LED)
- Jumper wires
- Breadboard
- USB cable for programming the Nano
Circuit Diagram & Connections:
Wiring:
LDR:
Connect one terminal of the LDR to 5V (positive).
Connect the other terminal of the LDR to an analog input pin (e.g., A0) and also to a 8 to 10kΩ resistor.
Connect the other side of the resistor to GND.
LED:
Connect the long leg (anode) of the LED to a digital output pin (e.g., pin 2).
Connect the short leg (cathode) of the LED to GND through a 220Ω resistor.
Arduino Code For LDR To On/Off LED
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