Is is feasible to build an audio recorder with SD card storage using ATmega 16 or 32 running at say 16 MHz?

If yes, what would it need in components? I don't expect you to make a device for me, but a high level overview of needed parts would be welcome.

I'm thinking of using an electret microphone and use the integrated ADC to capture audio and then save the signal to a FAT formatted SD card in a popular sound format if possible but if needed I could make a custom format and convert the data once it reaches PC.

I know that I'd of course need a power supply, SD card reader, microphone, AVR itself, but would I need some sort of filter at microphone's input? I'm mostly targeting human speech and it appears that I need to mainly focus at frequencies from 60 Hz to 7 kHz. I also heard that most of useful data is below 3 kHz.

Also right now, I don't have the feel for amount of memory the device would need, so if ATmega 32 is overkill, which smaller AVR would fit? I hope to go for as low pin count as possible.


Yes, it's feasible.

Here's a good tutorial for an MSP430 version (by Ian Lesnet of Bus Pirate fame).

  • \$\begingroup\$ Looks nice! I also found the AVR335 application note which describes use of ADC and storing data on flash memory. \$\endgroup\$ – AndrejaKo Jun 4 '11 at 19:19

definitely doable ( i just finished one with 8Khz sampling )

SD tricks are explained here : http://arduino.cc/forum/index.php/topic,49649.0.html

check timers from PCMAudio and http://arduino.cc/en/Tutorial/SecretsOfArduinoPWM

also http://letsmakerobots.com/node/28278 for the timers explanations

  • \$\begingroup\$ Nice answer! Also thanks for reminding me about this project. I spent quite a while working on this, but never actually got to the point of making it. \$\endgroup\$ – AndrejaKo Feb 20 '13 at 12:15

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