Arduino - Potentiometer fade LED

In a previous tutorial , We have learned how a potentiometer triggers a LED. In this tutorial, We are going to learn how to change the brightness of LED according to the potentiometer's output value

Hardware Required

1×Arduino UNO or Genuino UNO
1×USB 2.0 cable type A/B
1×Potentiometer
1×LED
1×220 ohm resistor
1×Breadboard
5×Jumper Wires
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About LED and Potentiometer

If you do not know about LED and potentiometer (pinout, how it works, how to program ...), learn about them in the following tutorials:

Wiring Diagram

Arduino Rotary Potentiometer LED Wiring Diagram

Image is developed using Fritzing. Click to enlarge image

How To Program

  • Reads the input on analog pin A0 (value between 0 and 1023)
int analogValue = analogRead(A0);

  • Scales it to brightness (value between 0 and 255)
int brightness = map(analogValue, 0, 1023, 0, 255);

  • Sets the brightness LED that connects to pin 3
analogWrite(LED_PIN, brightness);

Arduino Code

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-potentiometer-fade-led */ int LED_PIN = 3; // the PWM pin the LED is attached to // the setup routine runs once when you press reset: void setup() { // initialize serial communication at 9600 bits per second: Serial.begin(9600); // declare LED pin to be an output: pinMode(LED_PIN, OUTPUT); } // the loop routine runs over and over again forever: void loop() { // reads the input on analog pin A0 (value between 0 and 1023) int analogValue = analogRead(A0); // scales it to brightness (value between 0 and 255) int brightness = map(analogValue, 0, 1023, 0, 255); // sets the brightness LED that connects to pin 3 analogWrite(LED_PIN, brightness); // print out the value Serial.print("Analog: "); Serial.print(analogValue); Serial.print(", Brightness: "); Serial.println(brightness); delay(100); }

Quick Steps

  • Copy the above code and open with Arduino IDE
  • Click Upload button on Arduino IDE to upload code to Arduino
  • Open Serial Monitor
  • Rotate the potentiometer
  • See the LED
  • See the result on Serial Monitor
  • COM6
    Send
    Analog: 6, Brightness: 1 Analog: 34, Brightness: 8 Analog: 89, Brightness: 22 Analog: 149, Brightness: 37 Analog: 214, Brightness: 53 Analog: 297, Brightness: 74 Analog: 365, Brightness: 90 Analog: 431, Brightness: 107 Analog: 510, Brightness: 127 Analog: 589, Brightness: 146 Analog: 695, Brightness: 173 Analog: 790, Brightness: 196 Analog: 970, Brightness: 241 Analog: 996, Brightness: 248 Analog: 1018, Brightness: 253 Analog: 1023, Brightness: 255
    Autoscroll Show timestamp
    Clear output
    9600 baud  
    Newline  

Video Tutorial

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LED on Commercial Products

Small LEDs usually are used to indicate the status of devices. For examples:

  • TP-Link AC1750 Smart WiFi Router - Dual Band Gigabit Wireless Internet Routers
  • USB Hub 3.0
  • Gaming Keyboard and Mouse
  • Amazon Smart Speaker - Echo Dot

Big LEDs usually are used for lighting. They can be combined into groups. For examples:

  • LED Strip
  • Philips Hue

Potentiometer on Commercial Products

  • Digital Oscilloscope

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