1) Stethoscope. I picked mine up at a local drug store (Walgreens) for $10
2) A pair of Stereo Multimedia Microphones. Chosen because of the low cost and decent specs. $12 on Ebay.
3) 3.5mm (mini) Stereo Y-Adapter. ($0. I had one laying around but they are probably a couple of bucks)
Step 2: Disassembly...
I disassembled the multimedia microhones using an X-Acto knife and assorted tools. I cut it down the middle to get to the cabling and also popped the top off the header to get the mics out. I ended up with 2 mics and 3.5mm connectors.
Step 3: Stethoscope disassembly...
Remove the earpieces from the Steth. Then I drilled out the earpieces to the diameter of the mic housings. I used a Dremel with a grinding attachment to fine tune it.
Step 4: Reassembly...
I used a small dot of hot glue and inserted the microphones into the earpieces and then reassembled the earpieces on the Stethoscope.
Step 5: Final Results!
After plugging the two 3.5mm connectors into the Y-Adapter and then plugging the single stereo connector into my MP3 player, I was ready to test it out! Check out the video! Hope you like it and give it a try!