Turn Knob Controls Number of LED Pixels

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.


/* Control how many of Buzz's LED pixels are on with a turn knob */ #include "LEDStrip.h" //The LEDStrip.h library gives your code access to special functions exclusive to the LED Pixels LEDStrip wings = LEDStrip(16, A4, A5); //Set up the pixels by defining how many pixels (16) and where it's connected to Buzz (always A4 and A5) void setup() { pinMode(A0,INPUT); //turn knob } void loop() { int pixelCount = analogRead(A0); //create a variable named pixelCount that is an integer and checks the reading from the knob pixelCount = map(pixelCount,0,1023,0,15); //'map' the readings from A0 onto Buzz's //Now a reading of 0 on the turn knob = 0 on the LED strip. A light reading of 1023 = 15. A reading of 512 = 7 wings.clear(); //clear the pixels /* Create a variable i that has a starting value of 0 and, as long as i is less than pixelCount, run the code between the curly braces, then increase the value of the 'i' variable by 1*/ for(int i = 0; i <= pixelCount; i++){ wings.setPixel(i,random(0,300)); //Use the variable 'i' to set which LED pixel is being lit up } wings.draw(); //send the setPixel data to the LED pixels } // (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!

Buzz LED Pixel Color Spectrum

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

This graphic represents how some of the values from the turn knob will be "mapped" onto the colors of the LED pixels, except on Buzz you will map from 0 to 15, not 0 to 14.

Challenges

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Concepts

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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?