Using switch to control Piezo speaker

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]