EV3-G API: Sound

[dwalton76]

[dwalton76]

Per this video
https://www.youtube.com/watch?v=D2cGnTxsdy4

• play_type 0 is wait for completion
• play_type 1 is "play once"...I assume do not wait for completion
• play_type 2 is "play on a loop"

[dwalton76]

class Sound:
    """  
    Sound-related functions. The class has only static methods and is not
    intended for instantiation. It can beep, play wav files, or convert text to
    speech.

Unless anyone objects, I am going to make the Sound class follow the model of all of our other classes where it is expected that you create an instance of that class.

[ddemidov]

I think you can already create an instance of the Sound class and used it that way.

[dwalton76]

self isn't expected in any of the methods though...I don't think it would work. Either way will clean it up and make it consistent.

[ddemidov]

That's because the methods are static. The class is stateless, so self is not necessary. But the following works for me:

>>> from ev3dev.core import Sound
>>> s = Sound()
>>> s.beep()

[dwalton76]

The only musical instrument I can play is the radio. My musical ignorance is making play_note() challenging to implement. @EricPobot you wrote a lot of the code in this area earlier this year, would you be willing to implement that part of the EV3-G API for the Sound class?

[EricPobot]

@dwalton76 I'd be glad to help, but I'm not sure to see clearly what is expected to be done. I understand that it has some relation with an EV3-G connection but nothing more. I confess having been a bit away from ev3dev these last months, and thus have not followed its latest evolutions. Could you give me some input please ?

[WasabiFan]

Related: ev3dev/ev3dev#970

[EricPobot]

@WasabiFan I'm a bit confused. The related topic is about gathering sounds and graphics to be used with ev3dev. Not about software.

[dlech]

I think the question is how do you convert a musical note to a frequency. Here is a table from the official LEGO firmware.

_NOTES = {
  'C4': 262,
  'D4': 294,
  'E4': 330,
  'F4': 349,
  'G4': 392,
  'A4': 440,
  'B4': 494,
  'C5': 523,
  'D5': 587,
  'E5': 659,
  'F5': 698,
  'G5': 784,
  'A5': 880,
  'B5': 988,
  'C6': 1047,
  'D6': 1175,
  'E6': 1319,
  'F6': 1397,
  'G6': 1568,
  'A6': 1760,
  'B6': 1976,
  'C#4': 277,
  'D#4': 311,
  'F#4': 370,
  'G#4': 415,
  'A#4': 466,
  'C#5': 554,
  'D#5': 622,
  'F#5': 740,
  'G#5': 831,
  'A#5': 932,
  'C#6': 1109,
  'D#6': 1245,
  'F#6': 1480,
  'G#6': 1661,
  'A#6': 1865,
}

[WasabiFan]

@WasabiFan I'm a bit confused. The related topic is about gathering sounds and graphics to be used with ev3dev. Not about software.

Part of the EV3-G API lets you play named sounds (not paths, but preloaded sounds from a list). I'd imagine we will have some sort of support for that using the ev3dev-media package mentioned.

[ddemidov]

I believe our play_song should be enough to implement play_note: It plays a sequence of notes. (And the _NOTE_FREQUENCIES is a superset of the list @dlech provided).