How to make a Voice Recorder?

I want to make a voice recorder using an MCU(8051 or PIC). The recording time doesn't matter at this time. I just want to learn how to digitalize inputted voice by a microphone and write it to internal RAM. And after this I want to learn how to make it voice again from 1s and

0s format and send it to speaker.
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Tolga Onbay
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App note and source files:

Solid State Voice Recorder Using Flash MSP430

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You are never going to be able to use *Internal* RAM. Neither the PIC nor

8051 have more than a few 100 bytes. Generating sounds from a pre recorded sample stored in ROM is possible but still limited by the size of available memory

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gives a good guide to encoding sounds on a PC and playing back on a PIC.
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follows on from the above (costs $1.50 to purchase)

I would suggest looking at generating sound first, from samples recorded on a PC. Apart from anything else, if you start with the recording side you will end up with data that you have no idea as to whether it is correct or not.

An alternative approach is to look at recognising speech rather than recording it.

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Winbond make single chip voice recorder.

Need to look at pwm.

Basically record the voice on a pc , just a few seconds at a low mono sample rate. Then convert it to

Keil gives an example for their mcb2130 board. Examples comes with the eval version of their arm compiler. Just plays short samples of voice back using pwm.

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You can play music on the pic using a similar method. See

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ringtone example on a 16f877.

For recording voice, look at using the adc on the chip you have. To start with try hooking up a little electric mic to one of the adc inputs and sampling it. Could send it to a pc via the usart and record and plot it to see what resolution it gives.


Reply to
Alex Gibson

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