Arduino - Light Sensor Triggers LED
In this tutorial, We are going to learn how to:
- If the light sensor's analog value is lower than a threshold, turn LED on
- If the light sensor's analog value is greater than a threshold, turn LED off
Hardware Required
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 links direct to products from our own brand, DIYables .
Additionally, some links direct to products from our own brand, DIYables .
The LDR light sensor is very affordable, but it requires a resistor for wiring, which can make the setup more complex. To simplify the wiring, you can use an LDR light sensor module as an alternative.
About LED and Light Sensor
If you do not know about LED and light sensor (pinout, how it works, how to program ...), learn about them in the following tutorials:
Wiring Diagram
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Arduino Code
/*
* Created by ArduinoGetStarted.com
*
* This example code is in the public domain
*
* Tutorial page: https://arduinogetstarted.com/tutorials/arduino-light-sensor-triggers-led
*/
// constants won't change
const int LIGHT_SENSOR_PIN = A0; // Arduino pin connected to light sensor's pin
const int LED_PIN = 3; // Arduino pin connected to LED's pin
const int ANALOG_THRESHOLD = 500;
// variables will change:
int analogValue;
void setup() {
pinMode(LED_PIN, OUTPUT); // set arduino pin to output mode
}
void loop() {
analogValue = analogRead(LIGHT_SENSOR_PIN); // read the input on analog pin
if(analogValue < ANALOG_THRESHOLD)
digitalWrite(LED_PIN, HIGH); // turn on LED
else
digitalWrite(LED_PIN, LOW); // turn off LED
}
Quick Steps
- Connect Arduino to PC via USB cable
- Open Arduino IDE, select the right board and port
- Copy the above code and open with Arduino IDE
- Click Upload button on Arduino IDE to upload code to Arduino
- Radiates light to sensor
- See the change of LED's state
Code Explanation
Read the line-by-line explanation in comment lines of source code!
Video Tutorial
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