LED Strip Rainbow

Code

The code in the editor below is ready to run! Plug your Code Lab 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.


/* Turn on each pixel of the LED strip in sequence, changing the color value of each pixel */ #include "LEDStrip.h" //The LEDStrip.h library gives your code access to special functions exclusive to the LED Strip LEDStrip strip = LEDStrip(50, 13, 12); //Set up the strip by defining how many pixels (50) and which pins of the microchip are used (always 13 and 12 on Code Lab) void setup() { } void loop() { /* Create a variable i that has a starting value of 0 and, as long as i is less than 50, run the code between the curly braces, then increase the value of the 'i' variable by 1*/ for(int i = 0; i < 50; i++){ strip.setPixel(i,i*6); //Use the variable 'i' to set which LED pixel is being lit up //use the i variable times 6 (i*6) to set the color value. strip.draw(); //send the setPixel data to the LED strip delay(100); //delay 100 milliseconds (0.1 second) before running the 'for' loop again } } // (c) 2021 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!

Video Notes for Code Lab Users:

  • You will use “50” instead of “15” as the first argument in your LEDStrip function.

  • The second and third arguments of the LEDStrip function (13 and 12) do not need to change. These connections are permanently set on Code Lab.

  • Your “for” loop will run 50 times, not 15 times, because you have 50 LED pixels on your Code Lab.

  • Your color variable is i*6 instead of i*20 because there are 300 color possible color values. 300 color values divided by 50 pixels is 6. The video references an LED strip with only 15 pixels, and 300 divided by 15 is 20.

Use this spectrum to estimate the color values you'll need for your 'setPixel' arguments to achieve your favorite color!

Challenges

Can you complete the challenges? 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!

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?




2. Which syntax ends a single code command?