From: "Frank Bemelman"
References: <firstname.lastname@example.org> <email@example.com>
Subject: Re: How to implement an EEPROM for audio
Date: Wed, 18 Sep 2002 21:56:46 +0200
X-Newsreader: Microsoft Outlook Express 6.00.2600.0000
Organization: EuroNet Internet
NNTP-Posting-Date: 18 Sep 2002 19:56:56 GMT
"Richard Steven Walz" schreef in bericht
> In article <firstname.lastname@example.org>,
> Alex Bryant wrote:
> >First off, please excuse my ignorance, as I am fairly new to hobby
> >I am working on an animatronics project and hope to make some
> >improvements to the system. As is stands, I use an OOPic
> >microcontroller to queue all the events (detect start button, power up
> >lights, trip fog machine, etc.). One of these events is trigger a
> >discman to randomly select and play a track on a CD. The left channels
> >of these tracks are all audio (music and voice), and the right
> >channels are the movement signal that goes to the M5 animatronic
> >decoder. I would like to replace the CD player with an EEPROM that
> >would have all the tracks stored on it, in order to take a more
> >solid-state approach. The requirements are that it be able to store
> >(20) 60-second tracks with distinct left and right channels (as
> >opposed to mono), could detect when to play that track, and would
> >select that one track at random. They don't have to be
> >CD-quality....cassette quality seems to be good enough for the
> >Can anyone offer some advice on a product to use and how to implement
> >Thanks in advance,
> At CD resolution? My GOD that's a lot of EEPROMs!!!
> Even at 44.1kHz and thus 88.2kHz by Nyquist's sampling criterion,
> you would need twice that for two tracks, so 176.4kHz, and for 1200
> seconds is 211 MILLION bytes, and that's at 8 bit rez, you want 16 bit
> rez or 422 million bytes, or 400 something MByte EEPROMs. That's a lot,
> but they are making things bigger lately. You might want to use EPROM
> which is cheaper, and use bigger ones, like the 16 Mbit or 2MB for 200 of
> them, or use a 64MBit which is 4 times that for 50 of them.
> If your access is slow get a computer and hard drive!
CD resolution *is* 44.1kHz sampling, for 1200 seconds of 2 channels, 16 bit,
at 44.1 Khz you need 1200 * 2 * 2 (bytes) * 44100 -> 211 megabytes. At 8
it's less, 106 megabytes. Hey, that fits on a 'small' memorycard ;)
MP3 comes to mind. BTW, there is an improved MP3 now, MP3Pro. Cuts the
amount of data in half once more, and the quality is actually improved!
Up to 300 MP3Pro songs can be stored on a single CD.
Anyway, there are plenty of MP3 plans on the net, even complete
kits. I would use that, add some convenient interface for track
selection, modify the software a bit etc.
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