Any studio operator worth their Protools subscription will have a wide array of microphones to cover any conceivable situation. SM57s to cover guitar cabs, fancy gilded ribbon mics for vocal takes, and a variety of condensers to round out the selection. That’s all well and good for high-fidelity recording, but what if you want to go the other way? [LeoMakes] has just the thing, with his sub-$10 paper cup mic.
The basic concept is that of a dynamic microphone. A paper cup is attached to a taut string, upon which a magnet is affixed. Sound waves hitting the paper cup cause the string, and thus the magnet, to vibrate. The magnet is located within a coil, created from thin insulated wire wrapped around an old solder spool. This induces a current, creating the audio signal.
Results are as lo-fi as you’d expect, with the exact character of the sound changing depending on the tension of the string and the exact materials used. It’s a fun project that can be tackled with cheap materials, and there’s scope to create all manner of wacky mics by varying the parameters of the build. If you’re doing this more than once, however, you might want some help winding the coils — let this project be an inspiration. Video after the break.
Have done similar with middle school students at STEM interest building events. They were the follow up to the take-out box speaker, and the lead in to the solder up an amp table.
This was my first thought as well – the use of wire-wrap wire would make it less efficient (not really a consideration here) than standard magnet wire that you could just use on its (plastic) spool, but would allow kids to do the wrapping without having to be super careful with the varnish (and it could be re-used).
This could be the beginning of a VOIP Paper Cup Phone.
It definitely needs some string! Oh, and paper cups are bi-directional to.
Already done TCP/IP over a piece of string with an acoustic coupler
This reminds me of the Boise University TC1 vertical seismometer which suspends a magnet in a coil at the end of a slinky spring toy; I guess, as far as audio goes, the TC1 would be “all about da Bass”.