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10 years, 5 months ago.
Using microphone and detect sound
Hi I want to use simple electret microphone to detect voice. I have set-up and initial circuit and getting the values from the mbed. I am getting an output of 1 constantly from the mbed ADC and the output does fluctuate a little when there is sound but not much. What my question is how should i proceed with this now ?? what can i do with that data to check if there were some human in the room etc .
Can anyone help me with this. I am really stuck what should i do further
1 Answer
10 years, 5 months ago.
Use some op-amps to amplify the mic signal and to lift the amplitude above 0V (bias). This way, you will have the full scale on your ADC. Use rail to rail op amps.
RGDS
Thank you Gorazd actually i am using an Opamp and this is the reason why i am getting mostly a 1 at output of ADC because the Voltage is greater than 3.3V. What happens is when someone speaks into the microphone the voltage level goes low but not by much . i can get these values but don't know how should i proceed further ?? can you help me with this ?
posted by 12 Nov 2013Could you post the opamp schematic. When you simply want to detect a noise/sound level you amplify the mic signal, rectify it, integrate it to avoid spurious triggers, adapt the level to a valid range for the ADC and then sample it and apply a threshold to detect the soundtrigger.
You should prevent ADC voltages above 3V3 since this may damage the mbed.
posted by 12 Nov 2013
With using only a microphone this is more like a hardware project. Noise can be a problem if soldering is not right
posted by Dim O 01 Mar 2015