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Microphone Recorder

Microphone Recorder#

This document outline how the recorder can be used as a stethoscope This document contains:

  • Overview of the microphone recorder

  • Mold design of the recorder

  • Sample sound

Design#

Here is the image of the recorder microphone

USB

The picture above isn’t the full story though. For this design we use multiple modular parts, including the stethoscope head, the recorder, and the microphone.

sound_recorder sound_recorder

The main design of this device is from Dr. Lyndia Wu, I only modified the dimension and changed a little bit of one part, mainly to make an airtight seal.

This device sound quality is great, it also allows you to hear directly if you plug in your headphones in one of the jack. I personally find using this device easier, and a lot of the data I worked with also come from this device.

To turn it on, simply hold down the power button down for 3 seconds until you hear a sound from the recorder. Then insert your microphone to the microphone jack and the recorder should be recording.

Mold Design#

I provided the mold design in the github repo, it is in a solidworks file. If you prefer other file format contact me and I’ll gladly export it to you.

For the design, not much really to modify, devices works really great.

Sample Sound#

import numpy as np
import matplotlib.pyplot as plt
from scipy.io import wavfile
from IPython.display import Audio

audio_path = '../audio/recorder_sample.wav' 
sample_rate, data = wavfile.read(audio_path)

data = data/data.max()
audio = Audio(audio_path)
display(audio)

data = data / np.max(np.abs(data))

time = np.linspace(0, len(data) / sample_rate, num=len(data))

plt.figure(figsize=(14, 5))
plt.plot(time, data)
plt.title('Microphone Recorder Waveform')
plt.xlabel('Time (s)')
plt.ylabel('Amplitude')
plt.show()
../_images/e0b41e6ab89b514123e1929329fbda81412231069ea4082794ae61b24259eda0.png
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