[Robin Reiter] had a powered TV stand that only rotates around 20°, because who really needs their TV to rotate fully? He wanted to turn it into a motorized turntable for shooting videos, but first he had to hack it.
After opening it up [Robin] discovered that there was a surprising amount of electronics in the base. In addition to a DC motor, there was a potentiometer attached to a gear to give feedback, but it was set up for partial rotation so it had to be yanked out.
There was also a plastic gear with teeth around just part of the interior. [Robin] took a picture of the gear and dropped it into Fusion360, using the photo as a reference image while he re-created the gear. The new piece had teeth all around the periphery. After printing it out he glued it into the old gearbox, and now he had turned his TV stand into a motorized turntable.
Whether you’re selling a product or just showing off your latest project, a photo turntable makes video shots a lot easier. 360° turntables allow the viewer to see every side of the object being photographed, while the camera stays locked down. Motorized turntables are available as commercial products costing anywhere from $30 to $150 or so. Rather than shell out cash, [NotionSunday] decided to create his own turntable using a few parts he had on hand and 3D printing everything else.
The motor for the turntable came from the eject mechanism of an old DVD-ROM drive. An Arduino Pro Mini controls the motor’s speed using an MX1508 H-bridge chip. Power comes from an 18650 Li-Ion battery. The whole assembly spins on the head assembly from a VCR.
Before you jump in on the comments, yes, VCR heads have motors. However, they’re typically brushless motors rated for 1,800 RPM. Running a motor like that at low-speed would mean rewinding the coils. In this case, using a DC motor and gear drive was the easier option.
[NotionSunday] 3D printed the turntable base and mount. The mount uses a magnet arrangement that makes it easy to switch between freewheeling or belt driven operation. The turntable itself is posterboard, with 3D printed edges.
How do you consume your music, these days? Aside from on the radio, that is. Do you play MP3 or other files on your phone and computer, or perhaps do you stream from an online service? If you’re really at the cutting edge though you’ll do none of those things, because you’ll be playing it on vinyl.
A few years ago reporting on a resurgence of sales of vinyl records was something you would never have expected to see, but consumer tastes are unpredictable. Our red-trousered and extravagantly bearded hipster friends have rediscovered the glories of the format, and as a result it’s popping up everywhere. For those of us who are old enough to have genuinely been into the format before it was cool again, the sight of Sergeant Pepper and Led Zeppelin II on 12″ at outrageous prices on a stand at the local supermarket is a source of amusement. It’s good to see your first love back in vogue again, but is it really the £20($25) per album kind of good?
With the turntable having disappeared as an integral part of the typical hi-fi setup the new vinyl enthusiast is faced with a poor choice of equipment. Often the best available without spending serious money at an audiophile store is a USB device with the cheapest possible manufacture, from which the playback will be mediocre at best. We’ve lost the body of collective knowledge about what makes a good turntable to almost thirty years of CDs and MP3s, so perhaps it’s time for a quick primer.
A pleasing development for those with an interest in audio equipment from decades past has been the recent resurgence in popularity of vinyl records. Whether you cleave to the view that they possess better sound quality or you simply like the experience of a 12″ disk with full-size cover art and sleeve notes, you can now indulge yourself with good old-fashioned LPs being back on the shelves.
Behind the LEDs is the trusty LM3915, an integrated circuit which will no doubt be familiar to any reader whose earlier life was spent among 1970s and 1980s audio gear. Internally it’s a stack of comparators and a resistor ladder, and it simply turns on the required number of outputs to match the level on its input. He’s put a pair of them on a little PCB with an associated PSU regulator, and mounted the LEDs in a row of holes drilled in the MDF base board of the turntable following the edge of the platter. Power and audio come from the turntable’s circuit board, which contains a preamplifier and the USB audio circuitry. A traditional turntable with a low-level output would not be able to drive an LM3915 directly.
This is a relatively straightforward project and the turntable itself isn’t necessarily the most accomplished on the market, but it’s very neatly executed and looks rather pretty.
Conductive paints and inks have been around for quite sometime, and the internet abounds with examples of cool projects you can use them for. They’re well suited to quick and fun prototypes, educational workshops, and temporary toys. But, as cool as conductive paint is, it’s not usually the kind of thing that gets people excited at parties.
Well, until now that is. Adafruit has published a dope guide for building a bomb-diggity DJ mixing station out of a pizza box, conductive paint, and a Circuit Playground board. The guide walks you through how to properly apply the conductive paint (in this case using a stencil to lay it onto a cardboard pizza box), wire it up using the Circuit Playground, and integrate it into popular DJ software.
Sure, your sister’s “professional” DJ boyfriend may scoff at it, but it’ll still let you lay down some boss beats. And, when the bass drops nobody will care that you’re scratching a Domino’s box. Of course, there are other options out there if you want a more permanent solution.
On the face of it, playing a vinyl record is a simple process. You simply mount it on a turntable rotating at the right speed, and insert a needle into the groove. A learning exercise for youngsters used to be a passable attempt at a record player on the kitchen table with a pencil, a large cork, a sharpened matchstick, and a piece of paper. It sounded awful, but it demonstrated well how the audio was recorded.
If you have ever looked into the operation of a more conventional turntable though you’ll know that a little more care and attention is needed. There are many factors which affect the quality of the sound, and you quickly become obsessive about tracking, and sources of the tiniest vibration. Someone who has followed this path is [Mjhara], who has made a very high quality turntable. There is an unusual choice in this project: the tonearm is part of the build rather than fitting a commercial item like most turntable projects.
The platter is machined from a piece of rosewood, weighted and balanced with lead shot, and laminated between two sheets of brass. It sits on a bearing aided by a ring of opposing magnets, and is belt driven by a two-phase induction motor. The base of the turntable is cast as a single piece of concrete, the idea being that the extra weight will aid the damping of vibrations. The tonearm is machined from a piece of wood, and its pivot from brass. The tonearm bearing is a ballpoint pen, a surprising yet inspired choice .
Sometimes audiophiles take their quest for better sound to extremes, and justification for their expenditure can be very subjective. But [Mjhara] assures us that this turntable has an exceptionally good sound, and it is certainly a thing of beauty. Full details are in the Imgur gallery embedded below the break.