Amplitude Detection

hi all,

i'm working on class project , need (urgent!) in figuring out. have microphone goes through low pass filter. if run 1000hz sound our phone, on oscilloscope giving amplitude of 300 mv , if run 10k hz sound through microphone, giving amplitude of 30 mv or so. however, unable detect amplitude of these sine waves on arduino, , realized analogread function giving dc-rms voltage(1.6v in case) both frequencies. need know how figure out amplitude can differentiate between 1k , 10k hertz frequencies our phones. here's test program i've been writing figure out:

code: [select]


int sensorpinlowpass = a3;
int sensorpinhighpass = a0;
int sensorvaluelowpass  = 0;
int sensorvaluehighpass = 0;
float counter = 0;
float sum = 0;
int counterfinal = 10000;
int testnum = 1000;
int testcounter = 0;

void setup() {
  serial.begin(9600);
}

void loop() {
  while( counter < counterfinal){
    // read value sensor:
    sensorvaluelowpass = analogread(sensorpinlowpass);
    //sensorvaluehighpass = analogread(sensorpinhighpass); 
    //serial.println("amp low pass");
    //serial.println(sensorvaluelowpass);
    //serial.println("amp high pass");
    //serial.println(pow(sensorvaluehighpass, 2));
    sum  += pow(sensorvaluelowpass, 2);
    //serial.println(sum);
    counter++;
  }
 
  if(counter == counterfinal && testcounter < testnum){ 
    float finalval = sqrt(sum/counter);
    serial.println("finalval");
    serial.println(finalval);
    sum = 0;
    counter = 0;
    testcounter++;
  }
 
}

quote

and realized analogread function giving dc-rms voltage(1.6v in case) both frequencies.

no not, giving sample can anywhere between maximum , minimum peak values.

to envelope need either:-
1) put envelope follower between audio output , arduino input. can simple series diode , capacitor ground.

2) sample quick possible , record maximum value , hope somewhere close peak value. analogue digital converter can sample @ 10khz probbly not close this.

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