This mp3 player is in the form of a thin black 10” disk of shellac. It has a groove in the form of a circle near the outer edge. The groove is lined with micro-piezo actuators controlled by the centrally mounted processor. Mp3 files are loaded onto the device wirelessly. The waveform of the next 2/3 of a second of the audio is presented by the piezo groove. Pressure sensors in the groove keep the waveform aligned with the current position.
To play the audio, you need an antique wind-up gramophone in good working order. Place the disc on the turntable, wind up the machine, insert a new needle and lower the needle into penguin the groove.-- pocmloc, Dec 22 2012 HOWTO convert an MP3 to a playable, 3D printed record http://boingboing.n...-mp3-to-a-play.html [xaviergisz, Dec 23 2012] The Needle Wiggler The_20Needle_20Wiggler [Amos Kito, Dec 29 2012] (?) Horn Amp http://mint-technol...plifier-iphone-44s/doesn't turn though [Brian the Painter, Jan 01 2013] Cassette Tape MP3 Player [pocmloc, Oct 03 2019] Horn Amp https://web.archive...plifier-iphone-44s/Archive of [Brian the Painter]'s link [pocmloc, Jun 06 2020] Bizarre, pontless and unnecessarily complicated.
[+]-- 8th of 7, Dec 22 2012 [+]-- Kansan101, Dec 22 2012 A circular OLED screen in the centre displays cover art and track listing info.-- pocmloc, Dec 22 2012 A multi groove version could give random access to songs :-)-- piluso, Dec 22 2012 + because it made me think. I get it, I think. Are the peizos working to change their shape to create the sound? Or are they working like electromagnets? I think there should be several of these systems concentrically aligned so that changing tracks could be done by changing groves.-- evilpenguin, Dec 23 2012 [evil], I was thinking piezos which grew or shrinked to make an actual wiggly track for the needle. But perhaps, given that the needle is steel, it could run in a broad plain groove and strong electromagnetic fields could provide the wiggle?
Either way, the wiggle of the needle has to provide enough energy to drive the entire membrane & horn system and produce the sound.-- pocmloc, Dec 23 2012 If the 'record' had Wi-Fi, it could be a record of streaming radio-- hippo, Dec 23 2012 Thanks for the link, [xaviergisz].-- pocmloc, Dec 23 2012 [hippo], yes, but one winding usually only lasts 3-4 minutes. You can re-wind during playback of course.
Shellac records are abrasive and wear down the needle, but I don't see why our piezo-shaped groove should not be teflon-lined or something similar. That way you can continue playing till your winding arm muscles give out!
Also you could use the central OLED display to present video, and use the machine for watching live TV broadcasts. I am sure the video could be coded to rotate anticlockwise at 78rpm to give a static image on the spinning disk.-- pocmloc, Dec 23 2012 Really, you only need one piezo, as long as it doesn't move.-- BunsenHoneydew, Dec 29 2012 Why would you need to bother having a groove represent a whole 2/3 of a second? Seems to me that the only part of the groove that matters is the point directly under the needle. Couldn't you just have a servo that actuates a ring that moves up and down rapidly, and simply have the needle sit inside a groove on that ring? It's conceptually the same as those cassette tape car audio adapters—the “tape” is just a fixed head, and the magnetic value of that head changes with the audio on the input source. Same concept here, but varying the height of the “head” instead of its magnetism.
(On review, I think that's what [Bunsen] was getting at.)-- ytk, Dec 29 2012 The thing about the vintage gramophone is that the energy which drives the sound-producing mechanism comes from the spring motor. The motor turns the record, the record pushes the needle back and forth, the needle wiggles the soundbox window, and this pushes air down the horn which makes a noise come out the wide end.
I am sure there is a lot of loss and inefficiency in this system, but I am intrigued by the way a loud passage can make the record audibly slow down (my machine has a rather weak motor).
So I am thinking that the ideas mentioned here by [bunsen], [Y2K] and [bella], for just wiggling the needle, as also described in the linked idea //The Needle Wiggler// (thanks [amos]) would simply require rather too much power and would drain any battery thin enough to fit into a record disc. (of course, that idea was for 45s and LPs where the wiggling energy is much lower since electric amplifiers provide the power to drive the speakers).
That's why I wanted the rotation of the disc to drive the needle.
[bigs] can you elaborate? I don't quite follow your drift old bean.-- pocmloc, Dec 31 2012 [+] Might not sell a lot of these, my imaginary friends have some input here. They suggest placing your iphone in the horn using the external speakers. I will post a link of this baked version.-- Brian the Painter, Jan 01 2013 Annotations from Cassette Tape MP3 Player:
I want to see an implementation of an MP3 player into a large disk-shaped vinyl object that will reproduce accurately on a record player - advanced models will allow for scratching effects. — zen_tom, Jun 21 2007
[zen] Relatively easy to do - you just need to convert the sound into a varying magnetic field which would be detected by the needle pickups. — hippo, Jun 21 2007
That's ok for these new fangled record players - I should have been more specific - what I want is an mp3 gramophone record! — zen_tom, Jun 21 2007-- pocmloc, Oct 03 2019 Who's [bella]?-- notexactly, Oct 03 2019 Don't know, there's no trace of them in the first snapshot at archive.org, but that was almost a year later.-- pocmloc, Oct 03 2019 random, halfbakery