[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.
https://www.youtube.com/watch?v=zXQQFXG2uHA&feature=youtu.be
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.
I noticed this too with my electric guitar and earphones.
Was going to say the same thing :)
Like it, pam8403, got one hooked to some old stereo speakers and a 3.5 jack…might make another set with the coil for outside.
The same trick works for recording the sound track from copy-protected media, which is why doing any such copy protection is doomed to failure.
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 …
Heineken had such a speaker.
Here is someone who has modified it.
https://www.bartslinger.com/diy-projects/heineken-speakerkratje-bluetooth-upgrade/
I think that this is just showing that the phone supports HAC (lol ;)) Hearing Aid Compatible Telecoil support. Some phones wont work well depending on the speaker setup. http://www.betterhearing.org/hearingpedia/hearing-aid-compatible-cell-phones.
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.
Like putting a 90’s Nokia next to the head unit. Would hear every time it communicated with the tower and what was being said.
Back in the 60s we would use a coil to get to a telephone without making a connection to the sacred Bell owned wires.
https://goo.gl/G2yAVH
It is heartening to see that coils can still be connected to phones to serve the same purpose.
Old technology rules.
You can the same trick with a cassette deck; hook some earphones to a device of your choice and lay the earphones on the pickup element of the cassette deck. Press play and voila!
This is dumb…. You call this pairing? Sounds like amplified garbage
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.
maybe he wants to get a new iphone…