Using a PIC to record voice

[weirdjim]

Can somebody please point me in the right direction for a discussion of how to use the analog inputs on a pic and an external memory device to record voice -- say up to one minute of audio?

I searched the PIC site and came up empty; perhaps I used the wrong search terms.

Jim

[Ioannis]

You did not find any infos just because PIC isn't enough powerful to do such task.

I think a simple project of the kind was on Roman's Black site at http://www.romanblack.com/index.htm.

Ioannis

[Luciano]

Hi,

See this link:

Digital Sound Recorder with AVR
http://www.atmel.com/dyn/resources/p...ts/doc1456.pdf

Best regards,

Luciano

[RussMartin]

Have you considered using WinBond's ISD17xx family?

http://www.winbond-usa.com/en/content/view/160/290/

The audio quality is quite good at the 12kHz sample rate. It can be controlled in serial mode or in "push-button" mode. I have a PIC controlling two of these (ISD17180) at the same time in PB mode.

Unamplified volume is very good with a speaker driven directly from the complementary PWM output.

[Rob]

Have you considered using WinBond's ISD17xx family?

http://www.winbond-usa.com/en/content/view/160/290/

The audio quality is quite good at the 12kHz sample rate. It can be controlled in serial mode or in "push-button" mode. I have a PIC controlling two of these (ISD17180) at the same time in PB mode.

Unamplified volume is very good with a speaker driven directly from the complementary PWM output.

I would second RussMartin as I have looked into doing this in the past and then went down the Winbond route. Don't waste your time trying to get the PIC to do it; get yourself a dedicated speech chip and then use the PIC to address the speech chip. I use the Winbond ISD4002 which only gives 8kHz sample rate max. but allows 2 minutes worth of recording at this rate. This sample rate is absolutely fine for normal speech.

Regards

Rob

[weirdjim]

Rob and Russ, I've been using the IDC devices for about 15 years, but I'm trying to minimize silicon and real estate to the maximum extent possible. Luciano hit the nail pretty square on the head with his Atmel applications note...

Since the PIC I'm planning on using is doing about ten tasks at human speed ranges, my thought is to proceed through the ten tasks in order and when the "record" button is pressed enable an interrupt every 50 microseconds (20 kHz.) to do a sample, then return to the proceedings of the ten tasks. WHen the "playback" switch is hit, simply dump the contents of memory into the d/a converter (i.e. low pass filter) and sum the playback audio with the other audio sources in an opamp.

Speaker/phones audio is not necessary. I reduce all audio inputs to line level (1 volt/600 ohms) before I condition them, then provide them their own compsymm phones and speaker amplifiers.

However, any "don't go there" comments would be well received. I've reinvented too many wheels in my career.

Russ, I had forgotten that back in the '50s, I too was a "WN6BHI" who became a WB6BHI then went vanity call with WX6RST about ten years ago.

Thanks fer yer help...

Jim