[LAU] [OT] Open Source Portable Recorder?

[mark hadman]

You might have a little look at the Rockbox project - it's a mature
FOSS replacement OS for personal music players. It won't (yet) do
exactly what you're asking, but I'm be fairly sure that one or two
people will have suggested such a direction on the  forums over the
years.

On 7 January 2013 22:13, Len Ovens <len at ovenwerks.net> wrote:
>
> On Mon, January 7, 2013 9:42 am, Johannes Kroll wrote:
>> On Sun, 6 Jan 2013 08:48:35 -0800
>> "Len Ovens" <len at ovenwerks.net> wrote:
>
>>> As for hacking the unit itself, the first question is why. Not so much
>>> why
>>> you want to, but why would others want to. Before something gets the
>>> firm/software hacked there generally needs to be a reason at least a few
>>> people want to do so. Some extra functionality that is obvious (the
>>> smart
>>> phone has so much locked functionality it is frustrating so there are
>>> lots
>>> of hacks). The dr already seems to me to anything I would think of using
>>> it for,
>>
>> As to why, I can think of a few things:
>>
>>  - triggering recording at fixed time intervals, or based on some audio
>>    event like raised volume, or based on some external event, e. g. for
>>    syncing to a video camera
>>  - implementing USB audio so the device can be used as an external
>>    microphone. The recorders I've seen only output an analog signal.
>>  - changing recording parameters like custom sampling rates or different
>>    encodings. Commercial ones mostly do uncompressed WAV or MP3, but no
>>    lossless compression like FLAC for example.
>>
>> Other people probably have other ideas...
>
> I was not trying to say it shouldn't be hacked, just that there needs to
> be a large enough group of people who also see a need (or a why) for
> hacking it before there is much support (so that you are not doing the
> whole thing on your own). Those are all good reasons you have above (none
> of which I had thought of) I am sure more would show up out of need too.
>
>> Last not least, I simply like the idea of being in control of hardware
>> I buy.
>
> Nothing wrong with that.
>
>> As to price: the DSO nano is a free/open source oscilloscope which
>> isn't expensive at all, so building free and inexpensive hardware is
>> possible. Actually, using the DSO nano as a base could be a good
>> start for a recorder, it has A/D converters, mass storage and
>> everything... Just no mics.
>
> It could be a good base, but I think you may wish to add an A/d converter
> with more than 4bit sample depth (at least it looks like to me) and single
> channel. The sample rate is fine (though not fixed but variable so I don't
> know how easy to set to 48k or whatever), but takes lots of CPU as the cpu
> becomes part of the codec. However, there are lots of unused pins (i/o
> ports) on the cpu and it is open so the possibility of adding something is
> there. There is a schematic in the manual on
> http://www.seeedstudio.com/depot/micro-digital-storage-oscilloscopedso-nano-p-512.html
> for download which is where I got my info.
>
> It has a display, buttons, battery, USB port, etc. I might be tempted to
> add a second USB port (host instead of client) and use one of the cheap
> USB audio ports (parts all in the USB plug) and some $5 mics. I just found
> a great site for DIY mics That has some better pres than what comes with
> the little electrets. (its on my other computer :P )
>
>
> --
> Len Ovens
> www.OvenWerks.net
>
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