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Make voice recorder
Posted: Sun Sep 19, 2021 7:56 am
by saeed144
Hi everyone
I decided to make a voice recorder.
I know that I need a 44.1 kHz sample rate to cover the entire range of human hearing.
stm32f103 has 5MSPS ADC, can I use this?
Re: Make voice recorder
Posted: Sun Sep 19, 2021 8:20 am
by ag123
You can try using an
Electret_microphone on the ADC, a
transistor pre-amp may be needed, u'd need to test that. The stm32 ADC has high sample rates into the 1-2 million samples per sec. So you can experiment with the sample rates easily.
https://www.ncbi.nlm.nih.gov/books/NBK10924/
Humans can detect sounds in a frequency range from about 20 Hz to 20 kHz. (Human infants can actually hear frequencies slightly higher than 20 kHz, but lose some high-frequency sensitivity as they mature; the upper limit in average adults is often closer to 15–17 kHz.)
Re: Make voice recorder
Posted: Sun Sep 19, 2021 8:39 am
by saeed144
Thanks for your reply
One more question: How to select STM ADC sample rate in Arduino IDE?
Re: Make voice recorder
Posted: Sun Sep 19, 2021 8:51 am
by ag123
If sample rates isn't too high say < 100 ksps, you can try using a hardware timer to drive sampling and do an analogRead(pin), what is important is to set the pin mode pinMode(pin, INPUT_ANALOG); . analogRead() may be slow, if that is the case check the ref manual for your chip and figure out how to read the adc register, reading the register directly along with a timer can normally drive sample rates up to some 500 ksps.
using a hardware timer lets you fine tune your sample rates to high precision, nearly any sample rates you want. but the timer interrupt normally can't fire faster than 500 ksps.
Re: Make voice recorder
Posted: Sun Sep 19, 2021 1:32 pm
by mrburnette
saeed144 wrote: ↑Sun Sep 19, 2021 7:56 am
Hi everyone
I decided to make a voice recorder.
I know that I need a 44.1 kHz sample rate to cover the entire range of human hearing.
stm32f103 has 5MSPS ADC, can I use this?
Google this:
stm32 + voice site=github.com
research:
https://www.adafruit.com/product/1063
Re: Make voice recorder
Posted: Tue Sep 21, 2021 6:03 am
by saeed144
mrburnette wrote: ↑Sun Sep 19, 2021 1:32 pm
saeed144 wrote: ↑Sun Sep 19, 2021 7:56 am
Hi everyone
I decided to make a voice recorder.
I know that I need a 44.1 kHz sample rate to cover the entire range of human hearing.
stm32f103 has 5MSPS ADC, can I use this?
Google this:
stm32 + voice site=github.com
research:
https://www.adafruit.com/product/1063
Thank you so much
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