Buttons Raise and Lower Tone

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.

/* Pressing one button raises the tone on a speaker, pressing another button lowers the tone */ int pitch = 40; //create a variable named 'pitch' that is an integer (whole number) and has a starting value of 40 (where the speaker starts to sound good) void setup(){ pinMode(A5,OUTPUT); //speaker pinMode(8,INPUT_PULLUP); //button 1 (raises tone) pinMode(11,INPUT_PULLUP); //button 2 (lowers tone) } void loop(){ tone(A5,pitch); //play a hertz value equal to 'pitch' on the speaker if(digitalRead(8)==LOW){ //If button 8 is pressed pitch++; //raise pitch by one. With no delays, pitch will rise quickly! } if(digitalRead(11)==LOW){ pitch--; //lower the tone on the speaker // -- is shorthand for 'subtract one from the variable' } } // (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:

Your buttons are connected to ports 8 and 11 instead of ports 2 and 6 as the video says.

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!

Switch which button raises the tone and which button lowers it. Don’t forget to update the code comments if you are going to save your new code!

Add a delay after the pitch++; line of code and the pitch--; line of code. How does this change the program?

Add an ‘if’ statement so that if the pitch variable value goes below 40, the variable value is reset to 40. This will prevent negative tone values. This is a tough challenge!

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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