Recent content by CDAK1

  1. CDAK1

    Electronic Stethoscope

    Dear friends, Sorry for not being present for the discussion. Just like MP said, I've ,made a successful project (a gadget) out of the circuit given in this discussion. It successfully detects 25 different heart diseases and now I'm on my try to commercially implement this. But the problem...
  2. CDAK1

    Electronic Stethoscope

    MP, I haven't yet started further work in the project. It may take a few weeks to restart. (I finished my course in the current institution and may go back start working in another environment. So it may take few weeks to come back to the project again.) I shall inform every step in the...
  3. CDAK1

    Electronic Stethoscope

    MP, till now, I was extremely busy with my thesis work and was in a struggle to get proper result. Finally,my work ended with a success note. The credit goes to this forum too. I'll try ur expander circuit idea as I'm going to do more specialised work on the design of the stethscope part...
  4. CDAK1

    Electronic Stethoscope

    The second figure (normal heart beat from a standard e-steth)
  5. CDAK1

    Electronic Stethoscope

    The first figure
  6. CDAK1

    Electronic Stethoscope

    Sorry once again for the late reply. Thanks a lot MP and audioguru for the healthy discussion between u. Here I give my reply to some of the questions asked by u during ur discussion. The e-steth I made works fine with the circuit modified by me. I don't know whether LM387 is...
  7. CDAK1

    Electronic Stethoscope

    It's very difficult to get the fidility that a professional hi-fi e-scope gives, by the design over here. The main problem is the head design . We need specially designed head that absorbs sound of friction and other distant voices and sounds. Human body absorbs almost all sound...
  8. CDAK1

    Electronic Stethoscope

    Sorry for the delay, I couldn't come to the forum for a few weeks. I used my circuit to record a few heart sound. Here I give a plot of a heart beat (fig.1) recorded by my e-scope and fig.2 is the one downloaded from a medical site. The noise in my plot is from the surroundings(low frequency...
  9. CDAK1

    Electronic Stethoscope

    Thank u Bogdan, Infact, I had reduced the pre-amp gain.But later, found that for different people(patients), we need to vary the gain.So I introduced 2 more controls in the circuit.(in the pre-amp ckt only). One is in the microphone bias and the second is in the gain control. The circuit...
  10. CDAK1

    Electronic Stethoscope

    Here I suggest a modification to the e-scope circuit. Instead of using 741 everywhere, use the low noise pre-amplifier LM387 at a high gain at the input stage. In the attachment, it is given. U1 is LM 387 designed for a gain of above 500. It functions only above 10v eventhough it's minimum...
  11. CDAK1

    Electronic Stethoscope

    How good is this e-stethscope ckt in obtaining the real heart sound? Anybody tried? My work is related to that.( I can't go for an e-steth available in market as it is too expensive for me. ) I haven't yet started my work.I 'll inform u the outcome of each stage..thank u. :)
  12. CDAK1

    Electronic Stethoscope

    I got a doubt in the ckt.One of said, the last section is an amplifier, but without feedback will it work as a practical amp? Why do the usage of LM386 restrict to the last one only?(or what's wrong if one replace all 741 by 386 for better snr?)
  13. CDAK1

    Electronic Stethoscope

    Hi friends, :) I'm a new member from India. I found this site is very useful for the hardware people. As a part of my project (I'm doing my masters in Engg.), I've to make use of an e- stethoscope. So,I'm going to try out the circuit given here. But it will take some time to get some...
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