The 0.6.0 Software-Update just got released a few days ago. As they have pretty Limited Manpower for Software Development, i assume they put all their time and Energy into that update since this topic started, and the Situation regards the Alternate Trigers is still unchanged. Not sure how big of a priority they set themselfs for Implementing those Trigger Methodes, but i can see, why they would put Overall Image Quality and other Things way Higher in Priority, since it affects every user a lot more and increases Overall Value way more to an Average user, than those Triggers, where you are able to do a workaround with an External Trigger pretty easily, but not with Image Quality. Also most People will possibly never use any of these Options (though it would still be good to have them, just in case...).
So, even if they started to work on just that; full time/ full Power since the Release, it will propably still take a fair bit of time until this will be fully implemented and ready for a stable release, especially the Image Detection Stuff.
Also, keep in mind, there are a bunch of other things, that also need to be Implemented, which are supported in Hardware but not in Software yet, which could also be higher Priority than the Alternate Triggers for now.
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In my opinion, i think this can take a while until we will see that available in software. .
For Audio-Trigger you could try just some External microphone and some Circut that will give a Signal at a given Noise Level, to trigger the Camera, never did that myself, but shouldnt be all that hard to do, and could be a great workaround for now until its available in-camera. Not too sure about accereration, never worked with any Sensors for that.
