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November 25, 2009
about a year ago
Thanks - that’s good to know! :))
Thanks again, Byron.
I, too, am afraid real time FFT won’t be feasible.
Perhaps I can get away with the buffered approach, as the events I want to capture and FFT are not really continuous.
I’m thinking I could use another sensor e.g. movement sensor or even an extra sound detector (so one with the stock mic and the other with my own external audio source).
As soon as the stock board detects sound (using the binary indication already provided), it could trigger capturing from my custom audio source and then perform the FFT on the captured data.
I just hope I can get enough samples in the buffer and hope there is no other trigger event while the FFT is running.
Btw, regarding the sampling rate, I just spotted this very interesting thread:
Seems you can sample much faster than 10k and without loss of resolution, just by appropriately tweaking the prescaler value!
Thanks for your input!
I’m lucky in that I only work with frequencies up to ~4kHz. So the onboard 8kHz resolution (or 10k if we max it out :D ), is more than enough I suppose - which is great as I’d like to avoid having to use an external A/D.
In general, I’d like to keep everything as compact and energy efficient as possible, as I was hoping to develop something that can be deployed “in the field”, running off battery and/or solar power.
That’s why I’d hesitate to grab the Due unless I find it’s absolutely necessary - that and the relatively limited shield support and I/O voltage. [The same reasons make me lean towards Arduino instead of, say, a Beaglebone Black.]
Perhaps you’re right re. performance; I’ve found a couple of FFT libraries for Arduino but I guess I’ll have to “benchmark” them to be on the safe side.
I’d very much like to use this along with an external audio source, but what’s the max sampling rate one could achieve using this board connected to an Arduino’s analogue pins? For my application 8kHz are the minimum required (need to perform an FFT after that), but is it achievable?
No public wish lists :(
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