Using switch to control Piezo speaker

by Oscar

In this project, we will learn how to use a speaker (peizo sounder) and use switch button to change the pitch of the sound.

Sorry about this one, you might find it a bit difficult to digest at first, and I didn’t realise it’s actually harder than it sounds. Anyway, spend some time on the code, let me know if you have problem understanding the code, or you have a better solution.

In this project, we will be using a low power speaker called Peizo speaker (around 8 ohm) that look like this:
This program basically changes states as the button is pressed, between OFF, TONE1 and TONE2. This is the circuit diagram:
One thing we need to aware of in this project before we do any programming, is that, we will need to create a header file to store all the pitches as sensible names that we can use directly. Let’s create a new tap in the Arduino programming software:
 
 
And name it as “pitches.h”. Copy and save the following:
#define NOTE_B0  31
#define NOTE_C1  33
#define NOTE_CS1 35
#define NOTE_D1  37
#define NOTE_DS1 39
#define NOTE_E1  41
#define NOTE_F1  44
#define NOTE_FS1 46
#define NOTE_G1  49
#define NOTE_GS1 52
#define NOTE_A1  55
#define NOTE_AS1 58
#define NOTE_B1  62
#define NOTE_C2  65
#define NOTE_CS2 69
#define NOTE_D2  73
#define NOTE_DS2 78
#define NOTE_E2  82
#define NOTE_F2  87
#define NOTE_FS2 93
#define NOTE_G2  98
#define NOTE_GS2 104
#define NOTE_A2  110
#define NOTE_AS2 117
#define NOTE_B2  123
#define NOTE_C3  131
#define NOTE_CS3 139
#define NOTE_D3  147
#define NOTE_DS3 156
#define NOTE_E3  165
#define NOTE_F3  175
#define NOTE_FS3 185
#define NOTE_G3  196
#define NOTE_GS3 208
#define NOTE_A3  220
#define NOTE_AS3 233
#define NOTE_B3  247
#define NOTE_C4  262
#define NOTE_CS4 277
#define NOTE_D4  294
#define NOTE_DS4 311
#define NOTE_E4  330
#define NOTE_F4  349
#define NOTE_FS4 370
#define NOTE_G4  392
#define NOTE_GS4 415
#define NOTE_A4  440
#define NOTE_AS4 466
#define NOTE_B4  494
#define NOTE_C5  523
#define NOTE_CS5 554
#define NOTE_D5  587
#define NOTE_DS5 622
#define NOTE_E5  659
#define NOTE_F5  698
#define NOTE_FS5 740
#define NOTE_G5  784
#define NOTE_GS5 831
#define NOTE_A5  880
#define NOTE_AS5 932
#define NOTE_B5  988
#define NOTE_C6  1047
#define NOTE_CS6 1109
#define NOTE_D6  1175
#define NOTE_DS6 1245
#define NOTE_E6  1319
#define NOTE_F6  1397
#define NOTE_FS6 1480
#define NOTE_G6  1568
#define NOTE_GS6 1661
#define NOTE_A6  1760
#define NOTE_AS6 1865
#define NOTE_B6  1976
#define NOTE_C7  2093
#define NOTE_CS7 2217
#define NOTE_D7  2349
#define NOTE_DS7 2489
#define NOTE_E7  2637
#define NOTE_F7  2794
#define NOTE_FS7 2960
#define NOTE_G7  3136
#define NOTE_GS7 3322
#define NOTE_A7  3520
#define NOTE_AS7 3729
#define NOTE_B7  3951
#define NOTE_C8  4186
#define NOTE_CS8 4435
#define NOTE_D8  4699
#define NOTE_DS8 4978
Here is the code, notice we have to include the line “#include “pitches.h” to use our pitches names.

[sourcecode language=”cpp”]
/*
play sounds on a Piezo speaker. oscar’s project
Every time button is pressed, it moves to the next state. The states are:
Off – On(Note-C2) – On(Note-D3) – Off – …
*/

#include "pitches.h"

int buttonPin = 1; // button input pin
int speakerPin = 2; // speaker output pin

int buttonState = 0;
int beingPressed = 0;
int state = 0; // 0, 1, 2

// notes to play
int notes[] = {
NOTE_C2,
NOTE_D3
};

void setup() {

// initialize the LED pin as an output:
pinMode(buttonPin, INPUT);

}

void loop() {

// read the state of the pushbutton value:
buttonState = digitalRead(buttonPin);

if (buttonState == HIGH){
// this is only true for once after button is pressed
if (beingPressed == LOW){
if (state >= 2) state = 0;
else state++;
}
// this is the rising edge of the button signal
beingPressed = HIGH;
}
else {
// falling edge of the button signal
if (beingPressed == HIGH)
beingPressed = LOW;
}

if (state == 1)
tone(speakerPin, notes[0], 10); // param.:(output pin, pitch, duration)
else if (state == 2)
tone(speakerPin, notes[1], 10);
else
;// DO NOTHING

// give delay to let controller finish ‘tone’ instruction (same duration as ‘tone’)
delay(10);
}
[/sourcecode]

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