Turn Knob Controls LED Strip Color

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.


/* Use the turn knob to control the color of the LED strip */ #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() { pinMode(A0,INPUT); //turn knob in the smaller block of ports with the + and - ports } void loop() { int color = analogRead(A0); //Create a variable color that is an integer (whole number) and uses the analogRead of port A2 as its starting value color = map(color,0,1023,0,299); //Because analogRead has a range of 0-1024 and the color range is only 0-299, use 'map' //map matches up two ranges of values. Now, a 1023 analogReading equals color 299. A 0 reading equals 0. A 512 reading equals about 150 strip.setPixel(strip.ALL,color); //set all pixels to a color value of 200 and a brightness value of 'brightness' variable. strip.draw(); //send the setPixel data to the strip } // (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 turn knob is connected to port A0, not A2 as the video says.

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 values from the turn knob will be 'mapped' onto the pixel colors of the LED strip.

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!

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?