How to measure voltage using my sound card?

I want to measure the voltage signal over a coil using my sound card in real-time. I am using my microphone to input the signals but i'm not sure how to display the signal. I was using dsp.SpectrumAnalyzer to view the signal in dB.

Any help with how to convert and monitor this will be greatly appreciated.

Answer 1

[Walter Roberson]

If you are using winsound, then check

ai = analoginput('winsound');
out = daqhwinfo(ai);
out.InputRanges

if the output is

-1 1

then that is the most common case. In such a case, -1 corresponds to the most negative voltage the line can carry and +1 corresponds to the most positive voltage the line can carry, and absolute voltage is

Sample * Greatest_Positive_Voltage

[Adelaide]

Hi, I have a 64 bit system so i cannot use the Data Acquisition toolbox.

I am trying a different approach now:

 fs = 44100;  % Sampling frequency in Hz
  nbits = 16;  % Number of bits
  acq_ch = 2;  % Acquisition channels (stereo)
  secs2rec= 1; % Duration of recording
  object_setup = audiorecorder(fs, nbits, acq_ch);% creating object for recording
  recordblocking(object_setup, secs2rec)
  %play(object_setup);
  Recorded_data = getaudiodata(object_setup,'int16');
  plot(Recorded_data(:,2));
  hold on;
  plot(Recorded_data(:,1),'r')

I know with the 'int16' data type the range is -32768 to 32767.

Will this similarly represent the most positive and negative voltages?