This is something I've been thinking about for many years. Tonight I gave it greater thought on the way home, and even figured out ways to overcome some amount of the "big brother" aspects of it. But yes, essentially a mono 64kbits/s recording comes to under a GB a day. I would probably use a low end micro with just enough power to compress the audio a little bit, but I'd increase the bit rate so more advanced post-processing could take place later. It would still consume 1GB compressed, and post processing could re-compress it (MP3, OGG, etc) so a week could fit onto one CD. But that in and of itself isn't terribly useful. There are two other keys to the system that, if implemented correctly, could turn this into a tool regular people would want to use, rather than just geeks like me. I don't think you could/should put much intelligence into the recording bit. It might be fun the first few times you proved to your wife that what she said 10 minutes ago was unintelligible, but I imagine that behavior would be quickly stifled. So I'm going to have to go off, check up on some patents, get some quotes for the building blocks of the system, and make a business plan. Then laugh, put it all out online, and let someone else make money while I sit and smolder about my lack if initiative... The hardware should be pretty simple and "open source" so that anyone could plug their own hardware into the rest of the system. But it would have to be dirt cheap (including the gig of memory), last 48-72 hours on a single charge, last a full year (365 chrages) and still give 24 hours of use after 1 hour of charging, and be less than a 2" diameter, 1/2" thick button. Could probably make it last a week on a single AAA, if an ASIC was used. That's not trivial, but I believe a really well designed circuit should be able to pull it off. I've been wanting to get one of the tiny 100mAH li-poly batteries from sparkfun. -Adam On 11/6/06, William Chops Westfield wrote: > On Nov 6, 2006, at 1:55 PM, M. Adam Davis wrote: > > > > If I ever got around to making a "daycorder" all-day audio recording > > device, then I'd go with MicroSD simply because the device would have > > to be the size of a large button pinned on my shirt. > > Huh. According to some quick calcs, 1GB is about 26 hours of 8kbps > ("voice quality"?) audio. That's ... scary. > > Are there any tools that will take that GB of voice recording (mostly > rather quiet?) and extract the "interesting" parts (ie where there is > actually something to listen too?) Or is it better to try to put that > intelligence on the recording side? > > BillW > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Moving in southeast Michigan? Buy my house: http://ubasics.com/house/ Interested in electronics? Check out the projects at http://ubasics.com Building your own house? Check out http://ubasics.com/home/ -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist