Changing Color Pixel Bounce

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.


/* 'Move' a light up and down the LED strip, changing color with each new 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.clear(); //clear the old pixel off the strip so only one is lit at any time strip.setPixel(i,i*6); //Use the variable 'i' to set which LED pixel is being lit up, use i*6 to set the color strip.draw(); //send the setPixel data to the LED strip delay(100); //delay 100 milliseconds (0.1 second) before running the 'for' loop again } /* Create a variable i that has a starting value of 50 and, as long as 'i' is greater than or equal to 0, run the code between the curly braces, then decrease the value of the 'i' variable by 1*/ for(int i = 50; i >= 0; i--){ strip.clear(); //clear the old pixel off the strip so only one is lit at any time strip.setPixel(i,i*6); //Use the variable 'i' to set which LED pixel is being lit up, use i*6 to set the color 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.

  • Each of your “for” loops will run 50 times, not 15 times as the video says, because you have 50 LED Pixels. The video references an LED strip with 15 pixels on it.

  • The color value used for your LED pixels is i*6, not i*20 as the video says. Because there are 300 possible color values and 50 pixels, dividing color by 6 spreads the color range evenly across the pixels. The second time your “for” loop runs, it will use a color value of 6. The third time it runs, it will use a value of 12, and so on.

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?