Arduino Nano - Light Sensor LED

This tutorial instructs you how to use Arduino Nano and light sensor to trigger LED. In detail:

The light sensor is also known as photoresistor, light-dependent resistor, photocell, LDR. Arduino Nano measures the light level of ambience via a light sensor, if it is dark, Arduino Nano turns on LED and vice versa.

Hardware Preparation

1×Arduino Nano
1×USB A to Mini-B USB cable
1×Light Sensor
1×LED
1×220 ohm resistor
1×10 kΩ resistor
1×Breadboard
1×Jumper Wires
1×(Recommended) Screw Terminal Expansion Board for Arduino Nano
1×(Recommended) Breakout Expansion Board for Arduino Nano

Or you can buy the following sensor kits:

1×DIYables Sensor Kit (30 sensors/displays)
1×DIYables Sensor Kit (18 sensors/displays)
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Additionally, some of these links are for products from our own brand, DIYables.

Overview of LED and Light Sensor

If you are unfamiliar with LED and light sensor (pinout, functionality, programming ...), please refer to the following tutorials:

Wiring Diagram

The wiring diagram between Arduino Nano and Light Sensor LED

This image is created using Fritzing. Click to enlarge image

Arduino Nano Code

/* * This Arduino Nano code was developed by newbiely.com * * This Arduino Nano code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/arduino-nano/arduino-nano-light-sensor-led */ const int LIGHT_SENSOR_PIN = A0; // The Arduino Nano pin connected to light sensor's pin const int LED_PIN = 2; // The Arduino Nano pin connected to LED's pin const int ANALOG_THRESHOLD = 500; int analog_value; void setup() { pinMode(LED_PIN, OUTPUT); // set arduino pin to output mode } void loop() { analog_value = analogRead(LIGHT_SENSOR_PIN); // read the input on analog pin if(analog_value < ANALOG_THRESHOLD) digitalWrite(LED_PIN, HIGH); // turn on LED else digitalWrite(LED_PIN, LOW); // turn off LED }

Detailed Instructions

  • Connect your Arduino Nano to your computer using a USB cable.
  • Launch the Arduino IDE, select the appropriate board and port.
  • Copy the code above and open it in the Arduino IDE.
  • Click the Upload button in the Arduino IDE to compile and upload the code to the Arduino Nano.
Arduino IDE Upload Code
  • Emit light source towards the sensor
  • Check out the LED's state

Code Explanation

Check out the line-by-line explanation contained in the comments of the source code!

Video Tutorial

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