Detecting when playback has finished to play specified tracks one after another

[ashleycox]

Hoping someone can help. I’m trying to play files one after the other by specifying the file numbers, but I can’t figure out how to have the loop wait for the current file to finish before playing the next file. The files are speech samples, used to add text-to-speech functionality to an Arduino project. I want the files to play back to back with no (or as small as possible) delay as if they were joined together. So basically:

object.play(1);
As soon as 1 has finished:
object.Play(2);
As soon as 2 has finished:
object.play(3);
And so on.

The part I’m stuck on is getting the files of different lengths to play in this way, without resorting to delays and knowing the exact length. The files always get cut off. I’m basically struggling with the ‘if is playing’ bit. I've tried using the module's 'busy' pin with digitalRead but I'm still not getting anywhere. I'm sure there's something simple I'm missing, but I'd be grateful if someone can point me in the right direction or even offer a code sample to achieve what I'm trying to do. The DFPlayer mini is connected to an Arduino Nano using software serial. Any suggestions greatly appreciated.

[Makuna]

In your notification class (examples use the name Mp3Notify), the method OnPlayFinished(DfMp3& mp3, DfMp3_PlaySources source, uint16_t track) will be called when any track finishes playing. Just implement code that uses the passed track to figure out what the next track should be and call play with it.

[Makuna]

@terrypin999 I did target Arduino customers, but "notifications" concepts in general are not a simple topic and this device and the idea that you want to know when a song completes (a notification) requires a better knowledge of programming than copy and paste to "understand how it works".
Feel free to ask questions here or the gitter channel (https://gitter.im/DFMiniMp3/Lobby).
Asking on gitter is more ephemeral and some find it a more comfortable place to open up and ask questions they may think are stupid. Asking here is more searchable and retained.
I try to summarize interesting topics into the Wiki and its FAQ section (https://github.com/Makuna/DFMiniMp3/wiki) but it takes time and help is always appreciated.

[terrypin999]

Thanks Michael. I spent a few hours today returning to the original DFRobot library but once again it failed to reliably implement the sort of essential operations that I listed earlier. I’m now intending to work with PowerBroker’s library, but will later explore your more complex approach.

BTW, the FAQ you mention seemed to be empty, reporting ‘Under Construction’.

[jeremiawuzza]

I too have this problem (which one?) no seriously, If in my loop I call (say)
dfmp3.playMp3FolderTrack(3);
It starts to play, but if there is no delay() in the loop it only plays a short burst then repeats.
I put a delay() in the loop:
If the delay time is shorter than the track, the track is truncated - if it is longer there is a pause before the track repeats
Another track may be a different length and so it can't be controlled by different delay times. Or at least not precisely.

I see the
OnPlayFinished(DfMp3& mp3, DfMp3_PlaySources source, uint16_t track) method but I am not sure how to use it
for an sd card and say track 3 would it be
OnPlayFinished(DfMp3& mp3, DfMp3_PlaySources sd, 3) ?
And where does this go - in the loop somehow? or does it call another routine?

Please help - I am at the threshold of creating a beautiful thing with your <DFMiniMp3.h>!

[Makuna]

@jeremiawuzza Did you look at the examples? PlayMp3 example, demonstrates "implementing" OnPlayFinished(). It is not something you call, it's something you implement and that will get called when any track is finished.
The Wiki entry for it describes what the arguments will be when called and the examples

[Makuna]

I just updated the PlayMp3 example to play tracks 1-3 sequentially, looping forever. This demonstrates the simple technique.
You will have to pull (git term) of the source until the next release is made.