Articles, Blog

DIY Electronic Stethoscope

October 11, 2019


Hello and welcome to the TranslatorsCafe.com
Channel! In this video I will show you how to record the sound of your heart using a
stethoscope and a microphone connected to it. OK, first, the obligatory disclaimer. Of course I am not a doctor and cannot give any medical
advice. The device shown here cannot be used for any diagnostic purposes. Of course, only
medical professionals can listen to the heart sounds and make diagnoses. Ordinary mortals
like me cannot do such things. And of course if something goes completely wrong, for example,
the mains voltage appears on the stethoscope head or microphone and your body appears grounded
at this time, this device can kill you. In short, if you are going to repeat these experiments,
you have to know what you are doing. Recording heart sounds is relatively easy.
You will need a good microphone capable of recording low frequencies, an inexpensive
stethoscope, a recording device and headphones. It is also possible use a piezoelectric buzzer
or transducer as a contact microphone. I took it from an old smoke detector. The
stethoscope is not necessary if you will use the contact microphone. I tried both and discovered that the condenser microphone
combined with the stethoscope worked better than the contact microphone.
We will attach the microphone to the chest piece of the stethoscope using a short piece
of tube. The bell part of the stethoscope will be used for recording. The diaphragm
can be also used. In ordinary acoustic stethoscope the diaphragm is used to filter low frequency
sounds and to emphasize high frequency sounds at the expense of their amplitude. However,
in our case we can use software to amplify various frequencies and to remove some unwanted
high frequencies. Now, some theory. Heart sounds are generated
by beating heart, mostly by shutting heart valves, and the flow of blood through the
heart. The process of hearing these sounds for diagnostic purposes is called auscultation.
In healthy adults there are two main heart sounds that are called first and second heart
sound S1 and S2. The first sound is produced when atrioventricular valves (mitral or bicuspid)
and tricuspid valve are closed and the second sound is produced when semilunar (aortic and
pulmonary) valves are closed. Other sounds may be present if a person is not healthy. To hear heart sounds a stethoscope is pressed
to the chest at locations labelled with M (Mitral), T (Tricuspid), A (Aortic), P (Pulmonic)
and E (Erb’s point, the best for S2 auscultation). Now we will connect the stethoscope head with
the microphone to the recording device. Our electronic stethoscope is now ready for
recording my heartbeats. Later I will view the waveform of the recorded sound of my heart.
It is also possible to view its spectrogram that is a visual representation of the spectrum
of frequencies in a sound vs. time. The horizontal axis represents time, the vertical axis represents
frequency and a third dimension indicating the amplitude is represented by the color
of the image. For recording and playing back I will use
Thinklabs Phonocardiography powered by Audacity software that is free and can be downloaded
from thinklabs.com. We tried to show that it’s pretty simple
and inexpensive to record your heart beat sound, to listen and even to view it. Thank
you for watching. If you liked this video, please don’t forget to subscribe to the
TranslatorsCafe.com YouTube channel! All TranslatorsCafe.com videos are made in
English and Russian. All videos are provided with subtitles in these languages, which allow
using them to study technical English as well as technical Russian.

You Might Also Like

11 Comments

  • Reply OXXXYTOCIN May 8, 2016 at 5:15 pm

    сколько вашему сайту лет?

  • Reply TAEx熾紅蓮 August 25, 2016 at 5:52 pm

    can you record more heartbeat sound of your heart ? i'll really appreciate it^^!!

  • Reply Gleb Lebedev November 30, 2016 at 10:53 am

    Анатолий, подскажите что за микрофон вы использовали? Сходу не получилось найти такой же маленький конденсаторный микрофон.

  • Reply Levi Straatmann May 7, 2017 at 3:51 am

    ESTETOSCOPIO

  • Reply Vinith G May 14, 2017 at 8:18 am

    Hello Sir. Thanks for the informative video. Please provide details of where i can buy the same microphone you have used. I am from india and would appreciate if you could provide me the link to purchase it online.

  • Reply Soumitra Bhattacharyya October 28, 2017 at 6:47 pm

    I have created a DIY electronic stethoscope using the chest piece and connecting it to condenser mic over the tube. While I am able to hear all outside sound , I am not able to hear any body sound at all (heart/lungs) . The same chest piece when connected to tube of stethoscope works well . I am using audacity software for recording. I would appreciate any suggestions for resolving this . Thanks

  • Reply Michelle Guterman February 1, 2018 at 4:27 am

    What microphone did you use?

  • Reply bunberrier January 18, 2019 at 4:58 pm

    I can only assume the three downvotes were from mouth-breathers disappointed by the lack of naked women, robots, and explosions.
    That was very informative. I am interested in making recordings of my pets breathing and heartbeats as metrics of comparision as they age, so that I can detect problems that require medical care. Thank you Anatoly.

  • Reply ajay dhamija March 2, 2019 at 12:21 pm

    which mic has been used here

  • Reply Gabriella Herbek April 14, 2019 at 11:05 pm

    Can you please come and visit me sometime and listen to my heartbeat and can I listen to your heartbeat too and listen to your breathing

  • Reply Luca Bersiga June 28, 2019 at 7:19 pm

    Thank you SO MUCH for this video, it really helped me a lot!
    I've just managed to record my heartbeat with my new "DIY electronic stethoscope" (same mic, but I decided to use a pro stethoscope) and the final result is phenomenal!
    Now I can finally use the heartbeat samples in my horror soundtracks XD

  • Leave a Reply