Bluetooth Record Player Puts A New Spin On Vinyl

A portable Bluetooth turntable.

You know, we were just discussing weird and/or obsolete audio formats in the writers’ dungeon the other day. (By the way, have you ever bought anything on DAT or MiniDisc?) While vinyl is hardly weird or (nowadays) obsolete, the fact that this Bluetooth record player by [JGJMatt] is so modern makes it all the more fantastic.

Not since the Audio-Technica Sound Burger, or Crosley’s semi-recent imitation, have we seen such a portable unit. But that’s not even the most notable part — this thing runs inversely to normal record players. Translation: the record stands still while the the player spins, and it sends the audio over Bluetooth to headphones or a speaker.

Inside this portable player is an Arduino Nano driving a 5 VDC motor with a worm gear box. There really isn’t too much more to this build — mostly power, a needle cartridge, and a Bluetooth audio transmitter. There’s a TTP223 touch module on the lid that allows [JGJMatt] to turn it off with the wave of a hand.

[JGJMatt] says this is a prototype/work-in-progress, and welcomes input from the community. Right now the drive system is good and the Bluetooth is stable and able, but the tone arm has some room for improvement — in tests, it only played a small section of the record and skidded and skittered across the innermost and outermost parts. Now, [JGJMatt] is trying two-part arm approach where the first bit extends and locks into position, and then a second arm extending from there and moves around freely.

Commercial record players can do more than just play records. If you’ve got an old one that isn’t even good enough for a thrift store copy of a Starship record, you could turn it into a pottery wheel or a guitar tremolo.

70 thoughts on “Bluetooth Record Player Puts A New Spin On Vinyl

  1. Very cool concept – though I wonder if the arm will ever really be able to keep the needle in the groove properly, its spinning and wants to unfold quite hard with own interia I would think, along with changing the balance point of the whole system some when its more or less folded up…

    A counter balance that moves to match the distance of the arm, or just making it heavier so the rotating arm has less influence is probably going to help keep the player stable so the needle stays in the groove, and might be all that is really needed, love to see some more slow motion shots of its action.

      1. I avoided that word set for a reason, as this debate does my head in, all the terms are accurate and understandable enough to be very clear, so they should all be correct!

        With the varied force as the arm is more or less stretched out I’m not sure a spring could really be selected that will work for the whole record, at least not at all easily. Putting in one of those gear systems on the arm that locks the counter balance to the matching position of the arm perhaps? But without some slower footage of it working and failing its hard to know what is actually going wrong – maybe the arm just needs another pivot in it lightly sprung so it tries to remain in the right place but has that little bit of give before it can jump out of the groove.

        1. The biggest problem is, that the force depends on r² and for a simple counterweight r gets smaller while r of the needle-arm gets bigger.
          Perhaps a combination of a counterweight and a spring could solve this problem. You have a few degrees of freedom to optimize the function of force vs. extension angle, but it can probably only be optimized for one rotational speed.
          For the counterweight you can vary the angle of the arm relative to the needle carrying arm and of course it’s mass.
          With a spring you can vary it’s force and it’s pre-tension.

    1. A major flaw of this design is the change of angle the cartridge makes. The cartridge might be orthagonal to the groove at the mid section, but this is not the case at the inner and outer sections. Probably why it has trouble tracking at those parts.

      1. Looks to me like the way its supposed to close/open does keep the cartridge on the expected orientation – the arm is curved enough I assume it keeps the like well – probably better than the fixed arm record traditional players I would guess – but again really need to see it working or get the geometry for closer study

        1. The angular error depends only on the radius of the circle the arm is pivoting on, unless there is some fancy articulation to correct the error, which is not the case here. This is smaller (i.e., greater error) than any arm that pivots from outside the edge of the record.

          1. There is an ‘error’ in its position as its pivot moves round the circle to accommodate different radii, which can be corrected for if its actually audible by changing the speed of rotation very slightly to account for it – keeping the needles surface speed in the expected range despite lagging its pivot by more as the record plays..

            But the OP seems concerned with the angle of the needle cartridge to the record grooves – and this design looks to me to keep that better than the traditional record player – looks like the needle is always going to be perfectly aligned on the grooves.

          2. I see – the picture at the top is misleading. It shows the arm being one piece, which clearly didn’t work, since on the project page it shows a two-piece arm. However, in his description, the OP says that the inner arm “locks into place” and the outer one rotates freely, so that arm is still on a very short radius. I stand by my statement.

          3. And by the way, the shape of an arm has no effect on the motion between its pivot and its end. It can be straight, or it can wind around in c curlicue; the only thing that matters is the distance between the two points. The moving end will always move in a circle whose radius is the distance between the pivot and the moving end.

          4. With it looking two part (maybe in some images technically 3 part) what in my mind the curve was doing is making sure the the drag of the needle keeps it aligned with the groove, I haven’t read the source in that much detail, its a goofy project and I have things to get done…

            As when its two/three part the length from the pivot which in this case is effectively the centre of the record is varied so its arc over the surface isn’t tightly constrained to any one of the many lever arms real pivot points but the combined position of them all, which look like they should sort out to match the record..

            However looking at it again, but still at a glance, I really can’t figure out how its all supposed to be working, what is and isn’t supposed to be articulated… One of those rare cases where a good slower video clip of all the movement would be really informative, way more than most video clips vs the text that I usually hope accompanies them…

          5. Again, from what the builder writes, “I now have two arms, the first one extends out and locks into place and then the second arm moves freely on the end of the first.” I will repeat the relevant part: the first one extends out and LOCKS INTO PLACE.

    2. I really like the idea of keeping the record stationary and the record player itself moving. It also brings the concept of playing both sides. Perhaps it might be better to have a straight ridged arm that contains a long threaded rod, then mount the head perpendicular on a spring with a bearing and have the threaded rod follow the spring. Literally just mount two contacts either side and a limit switch at the ends. When the spring bends a motor turns and relieves the pressure and the spring will get rid of any vibration and allow the record groove to do the fine following freely.

      1. We had that in the early 1980ies from Sony. Although I am not sure if they used point contacts or optical sensors. Though there were for sure optical sensors to detect the size of the record and the “breaks” between different songs for an auto-seek function (if they were sufficiently “visible”depending on the record.

    1. Elaboration: they’ve demonstrated devices that look like a tall cylinder with a needle in the bottom. You put the device on a page of a book that has a record-style section and the device plays the audio from it. It was used for karaoke, you had the words and audio on one book page.

    2. There was something (I thought I saw it here on HaD) that was like a little car that drove itself around in circles on your record. Seems like it didn’t have anything connecting it to the center hole, though.

      1. I’ve been reading the posts on HaD for many years, I must say, I don’t recall that one, although I may have missed it.
        It sounds like an interesting concept though, certainly bringing a whole new meaning to, line following. Thinking about it, that’s a pretty tricky thing to get right. I guess, the lazy way would be to do the old lawnmower attached to a tree via a rope design and have it wind around a central peg, effectively just driving in a straight line, then you’d only need to consider a bit of dampening and wiggle room on the head.

      2. There was also a problem with speed. If you turn a disc around it’s center, the linear velocity changes with the radius. The little car had a constant linear velocity which was only correct in the middle of the record.

  2. I have owned many minidisc players including a 4 disc in dash and a 6 disc in trunk Sony set.

    I had a Tascam Dat recorder as well. I still have a tape laying around.

    Also, I have records and a reel-reel player/tapes.

    Minidisc was awesome…but having cheap storage nowadays kinda took away the need…but way better than CDs…they didn’t get destroyed in the car like CDs did.

    1. I first encountered MiniDiscs in my school theatre, where we had a portable recorder/player which was used for any sound effects or music required.
      The sound quality was higher than the tape it replaced, and being able to (almost) instantly skip tracks made it a lot more useful than cassette. The machine had an all-important ‘pause between tracks’ function, so all owe had to do was hit the play button at the right point in the script and it all just worked.

  3. The maker is going to need to measure the stylus downforce, there were tools made for this purpose years ago. Too little, and it will skitter out of groove as described, too much, and it will prematurely wear out the LP.

    Also, measure contact angle of the stylus. It needs to be aligned properly in the groove to prevent the same issues as improper downforce. The way the arm is designed, I suspect that is the major issue.

  4. Run the motor much slower, to avoid skidding and too much load on the record. Digitise the signal from the needle and buffer it. Speed up the buffered signal to the correct speed and play it.

    1. I’m guessing an optical mouse wouldn’t have enough resolution.
      But from experience I know a cheap 1.3/5MP web cam, with the focal range adjusted, does act as a very powerful microscope, with the right lighting, I wonder if it could read an LP in enough detail to reproduce intelligible sound.

    2. Use a photo sensor that sees 20 turns of the groove at a time, and you can reduce the rotation rate by a factor of 20. Don’t know why we’re still using destructive mechanical pickups on vinyl records, anyway.

  5. The player would have problems keeping equal pressure on each side of the groove even if it managed to stay in the groove. Looks to be a novelty and perpetuate the myth that vinyl sounds bad.

    Linear tracking is the ultimate for this and a Bluetooth transceiver the best wireless solution.

    But it’s a novelty piece so it will entertain..

    1. Indeed, I certainly wouldn’t want to use this on any record I was intending to keep scratch free.
      But all the same, it’s always nice to see innovation and creativity, every idea has to start somewhere.

  6. This seems like an excellent way to implement DRM on vinyl – after all it’s gonna play (decently) once.
    The tracking force from inertia alone is going to strip the groove dry, at least one stereo channel. Horrible.

    1. There’s a technology that was around for a short period called “Flexplay” which sealed DVDs in an airtight package, and once that seal was broken, the disc would degrade over the next couple of days so that it no longer played the movie.

  7. Bluetooth leaves much to be desired for sound quality which kind of defeats the purpose of spending extra money on vinyl. Plus, if this thing is skipping and skating, keep it away from my vinyl.

    1. I have always said that but look into all the specs for BT. Its a whole family of backwards compatible modes and at 5.0 there is a high def format now. The problem is you need 5.0 at both ends for it to work, and it’s hard to find out the details in a product description.

      I still would rather plug my headphones in than have to plug the ‘phones into the charger or not have them usable.

  8. the geometry is all wrong,hence it only works in one segment of the disk.geared motor is going to make it rummble grumble.

    instead have the arm wrap more than once around the player,with
    a second pivot in a location yet to be found.
    motor could be permanent magnet dc.
    keeping the whole player confined to the blank center section,playing good,and still non precious is going to an iterative process

  9. The reason this has never become production type technology is that it is poor sound quality and destructive to the record. Similar systems have been tried multiple times over the years.

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