Fade Up an LED Light

Code

The code in the editor below is ready to run! Plug Buzz in to your computer's USB port with the cable and hit 'Upload Your Code!' to see what it does. Change something in the code, like a delay or pin number. Try to add something new to the program - it's yours to tinker with! You can always press the 'Restore' button to return the code to the working example.

/* Fade up an LED light from 0-255 brightness*/ void setup(){ pinMode(3,OUTPUT); //LED on an analogWrite pin. Pins 3,5,6, and 9 can use analogWrite } void loop(){ /*create a 'counter' variable with a starting value of 0 and, as long as the variable is less than 256, run the code between the curly braces, then increase the value of i by 1 */ for(int i = 0; i < 256; i++){ analogWrite(3,i); //use the value of 'i' to determine the brightness of LED 3 delay(25); //wait 25 milliseconds (0.025 seconds) before running the 'for' loop again } //Once the 'for' loop has ended, the void loop will start over, resetting the i variable and running the 'for' loop again } // (c) 2023 Let's Start Coding. License: www.letsstartcoding.com/bsdlicense

Walkthrough Video

Watch the video for a line-by-line explanation of how the example program works. Then you'll be ready to make some changes of your own!

Challenges

Can you complete the challenge? Change the code in your code editor above. Upload your code to see the effect when you're finished. Complete a challenge? Check it off the list!

Change the delay inside the ‘for’ loop. Try to predict what will happen before you actually upload your new code.

Change the number that is the condition in the ‘for’ loop. In the example, that number is 256. What happens if you make it smaller?

Add more LEDs to this program. Remember that only LEDs 3,5, and 6 can fade up and down. You will need 1 new pinMode and 1 new analogWrite function for each LED you add to the program.

Concepts

These are the new code concepts covered in this example program. To become a great coder, read through these concepts to learn new vocabulary.

Quiz

If you're having trouble, try to run an experimental program or look at the example code to help you find the answer.

1. Which syntax ends the entire 'void loop' function?

semicolon ;
parentheses )
closing curly brace }

2. Which syntax ends a single code command?

semicolon ;
closing curly brace }
period .

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