pxt-calliope/docs/projects/banana-keyboard/code.md
Galen Nickel 350a98b429 Fixes to a couple of projects ()
* local commit

* Fixes to a couple of projects
2017-11-27 19:14:03 -08:00

3.1 KiB

Code

Have you ever tried making beat box sounds? Let's try making a beatbox with code and, yes, a banana!

Code the banana key

Start by adding a variable to store a musical note. Rename the variable to sound. Set the value of the variable to the note block Middle A from the Music drawer.

let sound = music.noteFrequency(Note.A);

We want to play music when the fruit connected to a pin pressed. So, we register an event handler that executes whenever pin 1 is pressed. Pin 1 is, of course, connected to the banana. Add a ||input:on pin pressed|| block from the Input drawer.

let sound = music.noteFrequency(Note.A);
input.onPinPressed(TouchPin.P1, () => {

})

Now, let's create some notes to play when the banana is pressed. Click on the Loops drawer then insert a ||loops:repeat|| loop into the ||input:on pin pressed|| block. Click on the Variables drawer and pull out a ||variables:change item by|| block and put it into the loop. Rename the variable to sound. Change the value from 1 to 25. This will increase the variable sound from the note frequency of block Middle A to Middle A plus 25 and so on. Put a ||variables:set to|| block for sound right after the loop. Set it to Middle A a in order to reset the sound after a banana press.

let sound = music.noteFrequency(Note.A);

input.onPinPressed(TouchPin.P1, () => {
    for (let i = 0; i < 4; i++) {
        sound += 25;
    }
    sound = music.noteFrequency(Note.A);
});

Finally, insert a ||music:play tone|| above the ||variables:change by||. Pull out the sound variable block and drop it in the note slot of ||music:play tone||. Change the beat fraction from 1 to 1/4.

let sound = music.noteFrequency(Note.A);

input.onPinPressed(TouchPin.P1, () => {
    for (let i = 0; i < 4; i++) {
        music.playTone(sound, music.beat(BeatFraction.Quarter));
        sound += 25;
    }
    sound = music.noteFrequency(Note.A);
});

Click |Download| and try a banana press. Did you hear 4 notes play?

Add another banana key

Go back to Make and repeat steps 7 and 8 with another banana but this time connect the crocodile clip to pin 3.

Duplicate the ||input:on pin pressed|| event handler to make a second one. For the new ||input:on pin pressed||, change the pin name to P2. In the pin P2 event, let's have the the frequency in the variable sound decrease by 25 instead of having it increase. Change the 25 in the ||variables:change by|| block to -25. OK, your code now looks like this:

let sound = music.noteFrequency(Note.A);

input.onPinPressed(TouchPin.P1, () => {
    for (let i = 0; i < 4; i++) {
        music.playTone(sound, music.beat(BeatFraction.Quarter));
        sound += 25;
    }
    sound = music.noteFrequency(Note.A);
});

input.onPinPressed(TouchPin.P2, () => {
    for (let i = 0; i < 4; i++) {
        music.playTone(sound, music.beat(BeatFraction.Quarter));
        sound += -25;
    }
    sound = music.noteFrequency(Note.A);
});

Click |Download| again and play both bananas. It's a fruit jam session!