stethoscope project!

[marydanny]

im working on a "make your own stethoscope" project but i am having a hard time hearing the heart beats from all three stethoscopes. What is it that i need to fix in order for this project to be a success?

[rmarz]

marydanny - I've not done this experiment, but have used numerous stethoscopes. The large open funnel is the end to be placed on the chest wall of the subject to listen to the heart beat. The contact with the 'patient' should be physically quite close to couple chest movement and it's moving air column to the listening end. What I might suggest, and this is just a wild idea, is to create an actual sealed membrane on the large funnel to be placed on the large funnel that consists of just stretching a plastic membrane, like Saran wrap across the funnel. This may help seal the sensor end and give you a better movement of air through the tube. I also think that the smaller diameter tubing will give you the best displacement of the air column and improve the amplification of the sound. A lot of guessing on my part, but it shouldn't take more than a few minutes to test the theory.

Rick Marz