Got any ideas?
Hi there,
Mbed community is full of ideas, but your description is insufficient.
- What device is playing those songs?
- How the Mbed will be connected to that device?
BR, Jan
I will share the code here later on and i want to know how to pause and resume the song using InterruptIn
use a single thread with thread::flags_set(pause or stop),
can give one example?
#include "mbed.h"
InterruptIn button(BUTTON1);
volatile bool pressed = false;
void buttonPress()
{
if(!pressed) pressed = true;
}
int main()
{
button.fall(callback(&buttonPress));
// main thread
while(1)
{
if(pressed)
{
// do something magic here
// clean after job done for another intrrupt
pressed = false;
}
// rest of loop
}
}
But there are many variants how you can solve it and it depends on your requirements. Usually simple InterruptIn - API references and tutorials | Mbed OS 6 Documentation or with combination of
- EventQueue - API references and tutorials | Mbed OS 6 Documentation
- EventFlags - API references and tutorials | Mbed OS 6 Documentation
BR, Jan
May i know why use callback instead of using &
I am not sure, but I did it like that, because that documentation says - void fall (Callback< void()> func ).
But probably it doesn’t matter because Callbacks are implemented also inside the API in this case.
Callback - API references and tutorials | Mbed OS 6 Documentation
BR, Jan
For the example u provided , does it helps when it pause the song and then the song will continue after resume button. I just no idea how to make the song pause at the tone and resume at the tone.
If I understand your code correctly you only periodically execute the tune_player function via ticker where is also incremented variable k (probably index of array of current song), set volume and so on.
So you can just make another if statement (with a bool variable connected to pause function) in your tune_player function what will mute speaker and skip incrementation of variable k.
BR, Jan
For example the music is running then I will pause it using button3 as an interrupt pin, then resume the tone using another button, but I no idea how to code it. I thinking on how to mute the speaker also , when I put speaker = 0 then it does not work. I also want to know like any code that can pause the tone , need some help on coding part .
I do not know/have your hardware so I can not make verified code.
void tune_player(){
if (k<allsongs[song_index].length){
if(pause){ //a boolean what will be controlled by your buttons
speaker = 0;
}
else{
//Set the PWM duty cycle to zero, if there is a sound pause
if(*(allsongs[song_index].note +k) == No) speaker = 0;
//Set the PWM period, which determines the note of the sound
else {
speaker.period(0.001*(*(allsongs[song_index].note + k)));
speaker = Volume;
}
k++;
//Set the time for the next ticker interrupt
timer.attach(&tune_player,(allsongs[song_index].beat[k]/3)+(allsongs[song_index].tempo/2));
}
}
else{
//If the musical piece is finished, start again
k = 0;
speaker = 0;
}
}
BR, Jan
You just added this line of code right , then how about resume it?
Yeah. You somewere must change valeu of variable pause. Probably something like this
volatile bool pauseButtonPressFlag = false;
volatile bool pauseState = false;
void buttonPausePress()
{
if(!pauseButtonPressFlag){
pauseButtonPressFlag = true; // set true for prevent another change before it will be processed
pauseState != pauseState; // negate last state
}
}
void tune_player(){
if (k<allsongs[song_index].length){
if(pauseState){ // if it is true, then it will skip playing next tone and also not increment the index, else it will be as normal.
speaker = 0; // off audio
pauseButtonPressFlag = false; // clean for another interrupt
}
else{
//Set the PWM duty cycle to zero, if there is a sound pause
if(*(allsongs[song_index].note +k) == No) speaker = 0;
//Set the PWM period, which determines the note of the sound
else {
speaker.period(0.001*(*(allsongs[song_index].note + k)));
speaker = Volume;
}
k++;
//Set the time for the next ticker interrupt
timer.attach(&tune_player,(allsongs[song_index].beat[k]/3)+(allsongs[song_index].tempo/2));
}
}
else{
//If the musical piece is finished, start again
k = 0;
speaker = 0;
}
}
BR, Jan
may I know what is mean by this pauseState != pause, then the pause is from? or Isit pauseState, not pause
My bad, sorry. Now it is correct I hope 
BR, Jan
You tried to send me a private message probably.
So what is it doing now?
BR, Jan
It can’t execute the if (pauseState) loop
Sorry, but that tell me nothing
Happy Birthday with Buzzer
#include "mbed.h"
#define TONE_A4 440
#define TONE_B4b 446
#define TONE_C4 261
#define TONE_C4_1 130
#define TONE_C5 523
#define TONE_D4 293
#define TONE_D4b 277
#define TONE_E4 329
#define TONE_F4 349
#define TONE_G4 392
// Happy Birthday
float notes[] = {TONE_C4_1,TONE_C4,TONE_D4,TONE_C4,TONE_F4,TONE_E4,TONE_C4_1,TONE_C4,TONE_D4,TONE_C4,TONE_G4,
TONE_F4,TONE_C4_1,TONE_C4,TONE_C5,TONE_A4,TONE_F4,TONE_E4,TONE_D4,TONE_B4b,TONE_B4b,TONE_A4,TONE_F4,TONE_G4,TONE_F4};
float interval[] = {4, 4, 8, 8, 8, 10, 4, 4, 8, 8, 8, 10, 4, 4, 8, 8, 8, 8, 8, 4, 4, 8, 8, 8, 12};
PwmOut buzzer(D5);
Timeout playTimeOut;
Timeout stopTimeOut;
InterruptIn bPlay(BUTTON1); //onboard button
InterruptIn bStop(D8); // external button
volatile bool bPlayPressed = false;
volatile bool bStopPressed = false;
void playButtonTimeOut();
void buttonPlayPress();
void stopButtonTimeOut();
void buttonStopPress();
int main()
{
printf("Buzzer melody test\n");
printf("Press Play button for PLAY or Pause and STOP button for.... you know\n");
bStop.mode(PullUp); // because of external button
bPlay.fall(callback(buttonPlayPress));
bStop.fall(callback(buttonStopPress));
int i=0;
printf("loop\n");
// The main thread
while(1) {
if(bPlayPressed){
printf("Play\n");
for (;i<(sizeof(notes))/sizeof(float);i++) {
printf("Tone %d\n", i);
if(bStopPressed){
printf("Stop\n");
i = 0;
bPlayPressed = false;
bStopPressed = false;
break;
}
if(bPlayPressed){
float tempTone = 1/notes[i];
if(tempTone != 0) buzzer.period((1/notes[i])); // set PWM period
buzzer=0.5; // set duty cycle
thread_sleep_for((0.8*interval[i]/10)*1000); // hold for beat period
}else{
printf("Paused\n");
thread_sleep_for(300);
buzzer=0;
i--;
}
}
printf("Over\n");
buzzer=0;
i = 0;
bPlayPressed = false;
}
// rest of loop
}
}
void buttonPlayPress()
{
bPlayPressed =!bPlayPressed ; // revert last state
bPlay.fall(nullptr); // interrupt OFF
playTimeOut.attach(callback(playButtonTimeOut), 300ms); // set interrupt ON after a time
}
void playButtonTimeOut(){
bPlay.fall(callback(buttonPlayPress)); // interrupt ON
}
void buttonStopPress()
{
bStopPressed = true;
bStop.fall(nullptr);
playTimeOut.attach(callback(playButtonTimeOut), 300ms);
}
void stopButtonTimeOut(){
bStop.fall(callback(buttonStopPress));
}
BR, Jan
May i know what is mean by this code?