This project shows how to control Fading LED Circuit using Arduino and Potentiometer and this potentiometer gives analog voltage; therefore, by rotating the potentiometer knob varies the voltage output and Arduino reads this variation.
Then Arduino reads it and changes LED brightness and this LED brightness changes smoothly; furthermore, the circuit is easy to make a simple project for beginners and Arduino lovers.
Arduino Code:
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:
| Components | Quantity |
|---|---|
| Resistor 1.5k 1/4 watt | 1 |
| Potentiometer 10k | 1 |
| Arduino Uno | 1 |
| LED any 5mm | 1 |
To begin with, in this above circuit potentiometer changes its internal resistance and this changes voltage at center pin of potentiometer VR1.
Arduino reads voltage level and converts voltage into PWM brightness and then LED brightness slowly increases or decreases when knob rotates.
After that, R1 resistor limits LED current to prevent burning out the LED and this works like manual dimmer.
Formula with Calculation:
The formula for the current through the LED 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, we used a 1.5k resistor in this circuit because it is the correct value.
How to Build:
To build a Fading LED Circuit using Arduino and Potentiometer follow the below connection steps:
- First, take all the parts as shown in circuit diagram.
- Next, potentiometer pin left connect to Arduino 5V
- Then potentiometer pin right connect to Arduino GND
- After that, potentiometer center pin connect to Arduino A0
- Now Arduino pin 9 connect to resistor 1.5k and LED positive and LED negative connect to Arduino GND
Conclusion:
To conclude, this Fading LED Circuit using Arduino and Potentiometer helps understand analog input and PWM output in Arduino.
Potentiometer controls LED brightness in smooth way and circuit uses only one LED, one resistor and one potentiometer, which is good for basic Arduino learning.