How do I connect a stethoscope to a speaker? How can I amplify a heartbeat through a speaker?

Hello, I am a student studying interdisciplinary sculpture. I am working on a project right now where I want the head of a stethoscope to connect to a speaker. I will need two of these, so at least two people can hear their hearts beating together at the same time. My idea is to have a rectangular column made of wood where I will embed the electronics/speakers. The stethoscopes and attached cords will come out of the column, enabling people to pick them up and use them.

Is this possible?
What kind of microphone can pick up the sounds from a stethoscope?

I have already searched the web for solutions and talked to teachers. So far I have not found a fool-proof solution. I have looked at acoustic and electronic/amplified stethoscopes. It seems that the best route will be to take the head of an acoustic stethoscope and embed a microphone into the tubing somehow which will then somehow connect to a speaker/microphone. Any help is greatly appreciated!

sort by: active | newest | oldest
StellaK151 year ago

I've been wanting to do the same thing. I was thinking maybe experimenting with a contact mic....

blkhawk5 years ago
I just found this electronic stethoscope schematic that might work for your project.
There's an alternative method which would be to build ECGs, which could be used to generate noise
i.saralynn (author)  steveastrouk5 years ago
I would like the sound of the actual heart beat. Noise/beeping might be an alternative though.
You have to ask yourself what IS "the sound of a heartbeat" - To a layman its the bass "lub-dup" you can hear when you put an ear to someone's chest, whereas a cardiologist is listening to the opening and closing noises of your mitral and aortic valves etc etc.

There was a great item at a UK Maker Faire last year, where two metal pads were used to pick up the RATE of the heart, and SFX used to make a heart noise.
Some heart conditions can be diagnosed by listening to their typical sounds. Also the sound of a patient's breathing help a physician diagnose certain conditions. That is why the OP asks to be able to amplify the sound from her stethoscope.
No it isn't it's for an art project according to the OP.
blkhawk5 years ago
You need to attach a microphone to the stethoscope.
blkhawk blkhawk5 years ago
There are very small microphones that you can use for this purpose. Check the Futurlec website. 
i.saralynn (author)  blkhawk5 years ago
Thanks! Do you know which of these microphones would be best for picking up these low frequencies? Then what kind of cable do I solder it to? Sorry if I seem clueless, this really is not my area of expertise.
It is hard for me to say since I am not familiar with the equipment that you intend to use. You can request more information from the vendor.
bwrussell5 years ago
You can use piezoelectric disks hooked up to amps and speakers. They might have to be placed against the neck because they react to the actual force of the veins moving.
Piezos are easy to wire and can be wired directly into guitar amps.
i.saralynn (author)  bwrussell5 years ago
I actually tried this last night. When I pressed the piezo against my skin, it just made a loud buzzing sound no matter where I put it on my skin.
From my experiences with piezos this means it's shorting or you are pressing to hard. Make sure the connections are sound, especially on any audio wires you've spliced in, and put something between your hand and the buzzer, maybe even a thin piece of cloth between your neck and the disk too.

I've used one up against my throat as a mic but it may not be sensitive enough to pick up a resting heart beat.
Do you have to have the actual heart beat or would any sound pulse and/or light flashing do?

I was thinking you could use a Pulse sensor and Arduino to detect each person's pulse and then you have the flexibility to offer up an audio and visual representation of the heart beat.

If your trying to use it to get people's hearts to sync up a visual and audio cue would probably be the most effective.
i.saralynn (author)  mpilchfamily5 years ago
I would prefer that actual live heart beat sound, but this would be a good alternate plan. Thanks!