Fade

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 ratio between on and off, to create a fading effect.

Step 1: What You Need?

1 x Arduino Board ( Arduino UNO R3 used in this tutorial.)
1 x LED(RED)
1 x 220 Ohm Resistor 
1 x Breadboard
Male-to-Male Jumper Wires

Don't have components? Don't worry. Just click the component's name. 

Step 2: Build Your 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 ground.

Step 3: Upload The Code.

1. Select the Arduino board type: Select Tools >> Board >> Select your correct Arduino board used. 

2.  Find the port number by accessing device manager on Windows. See the section Port (COM&LPT) and look for an open port named "Arduino Uno (COMxx)". If you are using a different board, you will find a name accordingly. What matters is the xx in COMxx part. In my case, it's COM3. So my port number is 3. 

Select the right port: Tools >> Port >> Select the port number.

3. You can find this code in the example of Arduino IDE.
Select File >> Examples >> 01.Basics >> Fade

Click press the "upload" button (see the button with right arrow mark).

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 pin to write to, and one indicating what PWM value to write.

In order to fade your 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 fadeAmount.

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.

Download: 

Arduino software

Sources:[https://www.arduino.cc/en/Tutorial/Fade]

Unknown

Author & Editor

My Robot Education Sdn. Bhd. (Robotedu.my) was founded in 2015 as the first robotics education centre in Malaysia to provide Arduino-based robotics courses for youths. Our vision is to be able to provide robotics education to every youth in Malaysia.