Forget Wifi Or Bluetooth, Pair Directly With Your Phone’s Speaker

[Kedar Nimbalkar] hyperbolically advertises the ultimate cell phone speaker dock. It costs a dollar. It doesn’t need you to pair with it via Bluetooth or WiFi. It pairs extremely fast, 0.000000000001, he clarifies. It may also look like a broken laptop speaker with a stomped wall wart soldered to it, but who can keep up with industrial design trends these days?

He shows us the device in operation. He starts playing some music on his phone’s speaker. It’s not very loud, so he simply lays the phone on the dock. Suddenly, all the audio fidelity a Dell Lattitude from the 90s can provide erupts from the device! How is this done?

Of course, there’s not much to the trick. Since the cellphone speaker is a coil it can induce a small current in another coil. The resulting voltage can be picked up by an audio amplifier and played through the speakers. Nonetheless it’s pretty cool, and we like his suggestion of betting our friends that we could wirelessly pair with their ear buds. Video after the break.

A coil can pick up a lot more sounds than you might expect – check out the Elektrosluch to learn more. If you want to learn more about coils and coupling, check out [James’] simulation.

14 thoughts on “Forget Wifi Or Bluetooth, Pair Directly With Your Phone’s Speaker

    1. Unless they make a voice coil piston enclosed inside a Faraday cage and connect such source of varying pressure to a membrane chamber (speaker) using a flexible tube. But then again, we can always transduce the sound waves back to varying voltage …

    1. people have been doing this since before hearing-aid-amplifiers fit inside the ear-piece of a heading-aid, they did this to record personal telephone conversations without needing to connect anything to the telephone line (at work = digital line) or on a payphone. there was a product sold that used this principle and attached using a suction cup to the back of the handset, this only workeed on earpieces/speakers and was not a microphone. it needed to be exactly lined up with the earpiece and might not work well with a telephone where the circuitry is inside the actual HANDset, go figure.

  1. Eh…doesn’t his phone have a headphone jack? Why over engineer a simple solution to short range audio transmission? He has to be like no more than a few inches away to inductively couple, and it introduces interference. Meh, it’s a hack but barely.

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