I have ordered pins to sodder onto this board, but at the moment, I have it wired up as shown in the attached picture (which may be the issue?)
The problem is, the audio output from the sound-detector board gives me a constant value on the arduino, whether there is sound coming into the microphone or not. The only time the value changes is when I unplug the sound-detector board from the power source, at which point I get values of 0.
The envelope detector output, however, works correctly. In a quiet environment, I get very low voltage values, and when speaking into the microphone, I get varying voltage values depending on how loudly I am speaking into the microphone.
However, for my application, I need raw audio-data and not the audio signal envelope.
Does anyone know what the issue could be, the code is very simply and shown below.
float i;
void setup()
{
Serial.begin(9600);
}
void loop() {
// send the value of analog input 0:
Serial.println(analogRead(A0));
// wait a bit for the analog-to-digital converter
// to stabilize after the last reading:
delay(2);
}
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When you attach an image it's helpful to embed the image so it's easy for everyone to see it at a glance. Instructions for doing this are found at: http://forum.arduino.cc/index.php?topic=364156.0
However, for my application, I need raw audio-data and not the audio signal envelope.
You also can't delay 2 milliseconds if you're going to read the audio waveform. i.e. CD audio is sampled at 44,100 times per second. The Arduino can't sample quite that fast but with a 2mS delay you're sampling at about 500Hz. But of course, you can't really "print out" the data at fast sample rates either.
DVDdoug:
You also can't delay 2 milliseconds if you're going to read the audio waveform. i.e. CD audio is sampled at 44,100 times per second. The Arduino can't sample quite that fast but with a 2mS delay you're sampling at about 500Hz. But of course, you can't really "print out" the data at fast sample rates either.
I am attempting to sample around 8kHz for my application. Below is some code I used to determine the sampling-rate with the basic analogread function.
// Arrays to save our results in
unsigned long start_times[100];
unsigned long stop_times[100];
float values[100];
// Setup the serial port and pin 2
void setup() {
Serial.begin(9600);
}
void loop() {
unsigned int i;
// capture the values to memory
for(i=0;i<100;i++) {
start_times[i] = micros();
Serial.values[i]=analogRead(A0);
stop_times[i] = micros();
}
// print out the results
Serial.println("\n\n--- Results ---");
for(i=0;i<100;i++) {
Serial.print(values[i]);
Serial.print(" elapse = ");
Serial.print(stop_times[i] - start_times[i]);
Serial.print(" us\n");
}
delay(6000);
}
The time I get, on average, is about 116 uS, resulting in around 8.6 kHz, which should be fine for my application. I realize in my initial code I was doing a
Serial.print(analogread(xyz))
command, which will greatly slow down the sampling rate. However, I plan on simply storing the values read at the analog input in an array, then continuing on from there with some feature extraction. I only need very small samples so the board memory size is not an issue. It was my mistake to post the Serial.print command in the original code.
Even now, I am still getting the same constant values at the analog input, around 1.2-1.5 volts, from the microphone audio output. These values do not change depending on whether it is completely quiet near the microphone, or very loud. I do not think this is a sampling rate issue, but maybe I am misunderstanding something? If I can get past this audio-output from the sound-detector board issue, I can move on with the rest of the project.
