High-Tech Spy Stethoscope!




Introduction: High-Tech Spy Stethoscope!

About: Tinkerer, hackster and prankster. Hit me up on Facebook: https://www.facebook.com/kipkayvideos/ Thanks for checking out my Instructables!
Hear through walls AND record what you hear with this High-Tech Electronic Spy Stethoscope for under $25! See the Test Results in the Video!

Step 1: What You Need...

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!



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    52 Discussions


    Question 3 months ago


    First, I was really impress with what you created with Stethosop, its ingenious.

    I watched your video several times and I think I found a similar Audio cable Mic and
    I wanted to show the ebay link and to make sure these will work?, when you open ebay ad, please select Option "with Mic" in the ad. Also, on the bottom of the ad they were just a whole bunch other cables listed just like these, its already has a mic and I guess I just need to get earpieces from the Steth to fit them in. And there is only connector at the end that would connect to the Y-adapter. wanted to get your check first and get feed back to see if I these work and If I understood your instructions before I purchase. I think these will work:


    How Is the Audio of this? can you hear people well? how well?

    If you're looking for the smallest GPS tracker with audio and video recording with MMS message, here you go:


    All you need to do is hide it somewhere in a room, under a table, in a closet or a handbag, it's so small nobody will even notice it.

    I found this YouTube video interesting:


    .One more thing, all the other schematics I have looked at using LM386 have pins #2 & #3 reversed from the schematic published here.

    This might not cause any problems, since nobody else has commented about this discrepancy.

    You are a genius!!
    I am a physician blood pressure specialist
    I need to measure BP sometimes 30 times a day
    This device is fantastic because I do not have to plug the dirty stethoscope ear plugs into my ears !!

    How could these microphones be connected to an amplifier/speaker instead of an mp3 player?

    If you want to spend $400 you can get a stethoscope for the hearing impaired that has an amplifier on it. Take the diaphragm and secure it to the wall with a bracket and then there will be headphones Not as fun as analog scanners before phones went digital but a nice party favor.

    no just makes two ports instead of one. your mp3 has to have a mic port & recording capabilities

    Well my MP3 has a built in microphone, so I can't make this without a new MP3 player.

    wierd thing is i was using my earbuds and the apparently the mic only picked up the sound from the left side o.O

    Thanks for sharing I'm know what I'm going to be doing while on vacation.

    i think that if u put only one mic into one earpiece and leave the other earpiece alone, u could hear wot u r recording and record only the info u need.

    Buy a spy ear kids toy, open it up, desolder the mic and resolder it with longer wires..... use this for your mic (doing it with just one mic as per your other comments). I added a 1.5AA battery to mine instead of the button cell. Gives nice amplification and a handy headpohne input jack to give the option if listening direct or plugging it into a recorder.

    Wouldn't it be easier to just buy the condenser mics from Radio Shack? I know they sell them.