Led Fading Using Arduino UNO | Led Fade | Fading | Led Control Using Programming #Fading #Arduino

Let's learn to adjust an LED's brightness using one of Arduino's analog outputs. You've probably already learned how to use Arduino's digital i/o pins to send HIGH and LOW signals to an LED, but some of these pins are capable of simulating a signal somewhere in between.
This example demonstrates the use of the analogWrite() function in fading an LED off and on. AnalogWrite uses pulse width modulation (PWM), turning a digital pin on and off very quickly with different ratios between on and off, to create a fading effect.

Hardware Required
Arduino board

LED

220-ohm resistor

hook-up wires

breadboard

Circuit
Connect the anode (the longer, positive leg) of your LED to digital output pin 9 on your board through a 220-ohm resistor. Connect the cathode (the shorter, negative leg) directly to the ground. Code
After declaring pin 9 to be your ledPin, there is nothing to do in the setup() function of your code.

The analogWrite() function that you will be using in the main loop of your code requires two arguments: One telling the function which pins to write to, and one indicating what PWM value to write.

In order to fade you're LED off and on, gradually increase your PWM value from 0 (all the way off) to 255 (all the way on), and then back to 0 once again to complete the cycle. In the sketch below, the PWM value is set using a variable called brightness. Each time through the loop, it increases by the value of the variable fade amount.

If brightness is at either extreme of its value (either 0 or 255), then fadeAmount is changed to its negative. In other words, if fadeAmount is 5, then it is set to -5. If it's -5, then it's set to 5. The next time through the loop, this change causes brightness to change direction as well.

analogWrite() can change the PWM value very fast, so the delay at the end of the sketch controls the speed of the fade. Try changing the value of the delay and see how it changes the fading effect.