Fading LED Circuit using Arduino and Potentiometer

This project shows how to control Fading LED Circuit using Arduino and Potentiometer.

Potentiometer gives analog voltage.

By rotating the potentiometer knob varies the voltage output and arduino reads this variation.

Arduino reads it and changes LED brightness and this LED brightness changes smoothly.

It is easy to make a simple project for beginners and Arduino lovers.

Arduino Coding:

int pot=A0;
int led=9;
int val=0;

void setup()
{
pinMode(led,OUTPUT);
}

void loop()
{
val=analogRead(pot);
val=map(val,0,1023,0,255);
analogWrite(led,val);
}

Code Explanation:

• analogRead reads value from potentiometer.
• Value is between 0 and 1023.
• map function converts it to 0 to 255.
• analogWrite sends PWM to LED on pin 9.
• Low value makes dim LED.
• High value makes bright LED.
• Loop repeats always.

Circuit Working:

Parts List:

In this above circuit potentiometer changes its internal resistance.

This changes voltage at center pin of potentiometer VR1.

Arduino reads voltage level and converts voltage into PWM brightness.

LED brightness slowly increases or decreases when knob rotates.

R1 resistor limits LED current to prevent burning out the LED.

It works like manual dimmer.

Formula with Calculation:

Formula for current through the LED is given by ohms Law:

I = Vsource​ − VLED​​ /R

where,

• Vsource​ is 5 V Arduino output
• VLED is 2V for a typical red LED
• R is the resistor value 1.5 k

Voltage across resistor = 5V – 2V = 3V

Current needed = 2mA approx since using 1.5k resistor

R = V ÷ I = 3v ÷ 0.002A = 1500 ohm

So 1.5k resistor is correct value we used in this circuit.

How to Build:

To build a Fading LED Circuit using Arduino and Potentiometer follow the below connection steps:

• Take all the parts as shown in circuit diagram.
• Potentiometer pin left connect to Arduino 5V
• Potentiometer pin right connect to Arduino GND
• Potentiometer center pin connect to Arduino A0
• Arduino pin 9 connect to resistor 1.5k and LED positive
• LED negative connect to Arduino GND

Conclusion:

This Fading LED Circuit using Arduino and Potentiometer helps understand analog input and PWM output in Arduino.

Potentiometer controls LED brightness in smooth way.

Circuit uses only one LED, one resistor and one potentiometer.

This circuit is good for basic Arduino learning.

References:

LED Fade Series Using Potentiometer