Measuring microphone amplitude

[Pseudoabdul]

Hi,

I'm very new to teensy so this is probably a simple question but I'm still a bit stumped after searching the forums and tutorials.

I am trying to print out a real time amplitude value of the incoming microphone signal. I have modified the microphone test example to do this:

#include <Audio.h>
#include <Wire.h>
#include <SPI.h>
#include <SD.h>
#include <SerialFlash.h>

#include <Audio.h>
#include <Wire.h>
#include <SPI.h>
#include <SD.h>
#include <SerialFlash.h>

// GUItool: begin automatically generated code
AudioInputI2S            i2s1;           //xy=149,228
AudioAnalyzePeak         peak1;          //xy=407,266
AudioOutputI2S           i2s2;           //xy=447,200
AudioConnection          patchCord1(i2s1, 0, i2s2, 0);
AudioConnection          patchCord2(i2s1, 0, i2s2, 1);
AudioConnection          patchCord3(i2s1, 0, peak1, 0);
AudioControlSGTL5000     sgtl5000_1;     //xy=339,338
// GUItool: end automatically generated code

void setup() {
  Serial.begin(9600);
  AudioMemory(8);
  sgtl5000_1.enable();
  sgtl5000_1.volume(0.5);
  sgtl5000_1.inputSelect(AUDIO_INPUT_MIC);
  sgtl5000_1.micGain(36);
  delay(1000);
}

void loop() {
  Serial.println(peak1.read());
}

The only output it get is 1.0 with an occasional 0.0. This remains unchanged even if I unplug the microphone. The microphone seems to be fine as I can hear the signal.

I am using a Teensy 3.2 with the audio shield.

Thanks.

 

[WMXZ]

Hi,

I'm very new to teensy so this is probably a simple question but I'm still a bit stumped after searching the forums and tutorials.

I am trying to print out a real time amplitude value of the incoming microphone signal. I have modified the microphone test example to do this:

......


The only output it get is 1.0 with an occasional 0.0. This remains unchanged even if I unplug the microphone. The microphone seems to be fine as I can hear the signal.

I am using a Teensy 3.2 with the audio shield.

Thanks.

Before you go on with trying to understand the (non)results, you should slow down the printout. The teensy is far too fast, so that

void loop() {
  Serial.println(peak1.read());
}

will overwhelm the PC, risking further to get a non-responsive USB connection to the teensy

To start I would do a peak reading say 10 times per second , so you can read the value on the screen by inserting a delay(100);

void loop() {
  Serial.println(peak1.read());
  delay(100);
}

later on you you can always shorten the delay.
However, going below 3 ms , is not useful as audio data are processed in chunks of about 3 ms

 

[manitou]

FWIW, your sketch works for me with delay(500); in loop(), i get values from 0.02 to 0.88 for various noises into mic

Try delay(5) and multiply peak by 100 and feed into Serial Plotter in IDE

i am using the Teensy microphone attached to the audio adaptor