DIY Voice recorder
Oct 28, 2008 at 11:18 PM Thread Starter Post #1 of 2

MrSiki99

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I was just wondering if anyone here has experience or knows the basis of building a DIY Voice Recorder. My friend and I are doing a project and are having a difficult time finding anything on the web and so I figured maybe someone here has some knowledge on where to start.
 
Oct 29, 2008 at 3:37 AM Post #2 of 2

error401

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The basic idea is ADC -> memory. If I was just doing this for low quality audio, I think I'd go with a small(ish) microcontroller and use its internal ADC to sample into some flash. You can use the uC's EEPROM to store the index. A fairly simple 2-3 IC solution is possible with this approach. You will need to write some firmware, but it's definitely easier and more flexible than going all-hardware.

Choose between SPI and Parallel flash. SPI is easier to interface, comes in more DIY-friendly packages - but it's got lower capacity and takes more microcontroller resources to use. Parallel is cheaper, much higher capacity - but it requires a large number of interface pins and has a more difficult to handle interface (though some uCs will have a controller integrated - like the AT91SAM7 series). You could also use SD/MMC (SPI interface) cards.

An AVR ATmega is probably up to the task, and it's easy for DIY. For a tad more power something like the AT91SAM7S32 might be a good choice (48TQFP, ARM7 core). There are other options out there too, some of the larger PICs can handle this. There are lots of fast 8051 variants out there, and tons of other (and much larger/faster) ARM cores too. If you go with something with less than 8K of SRAM you'll probably need to add an external SRAM to buffer the flash.
 

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