Adding audio output (with small speaker)

[Christophe]

I was wondering how I could add audio playback to the GameFrame, in order to have sound notifications in synch with event animations, when I need to attract attention in a room.

Looking at the Photon board specs (https://docs.particle.io/datasheets/photon-datasheet/#pin-markings), I see that it has two 12-bit DAC pins already present (pins DAC and A3) but they probably can’t drive a speaker directly.

# Hardware requirements:
– amplifier that can drive a (small) speaker. I have no idea what kind of power would be required to drive a small HP that can play audible sound when you are 4 to 5 meters aways, without beeing too loud either. I’m sure stereo is overkill so only one speaker is required here.
– where/how to mount the speaker?
– power? if the speaker isre small enough, I guess the opamp could be driven from the 5V ramp without issues…
– heat created by opamp? (again if small enough this may not be an issue)
– space constriants: the Photon board is already preventing me from screwing the backplate completely, so it does not seem possible to add another shield on top of it.

# Software requirements:
– how to attach sound to animations? should sound be considered as part of a animation (ie: a ‘sound.wav’ file present in the folder). should it be loopable? whan happen if audio is longer than the animation?
– file format for sound? I suppose very basic mono 8-bit or 16-bit WAV files with low sample rate (16Khz? 22.05KHz ?) could probably be good enough?
– MP3/OGG support? this could be a killer for perf since as I understand the ARM processors do not have the cpu instruction to do the DCT in hardware, and I think adding an MP3 decoder board would be overkill here..?
– audio level, mute ?

# Human requirements:
– I suck at soldering so I would prefer solutions where I only need to plug/connect some wires together, and maybe glue things to the frame 🙂

Has anybody already thought about this and/or knows about already existing breakout boards or shields that can be plugged to the Photon, and could be mounted in the GF itself?

[Patrick]

I thought about adding sound but not by modifying the Photon. I considered using IFTTT to use the same trigger twice. (2 applets, both have same trigger) Once to trigger an animation, another to play a sound. Not sure if that would even work, or what wifi device could be used to play a sound file.

[Author]

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