I'm somewhat obsessed with Laserdiscs. As my collection grows so does my fear that my player will fall apart. I've already fixed it once, and I have two of the same model so I have some amount of spare parts, but eventually something unrecoverable will happen and I'll have to find a new one. The problem is: there's no new Laserdisc players.
This morning I woke-up thinking about what it would take to make a Laserdisc player myself. The electronics are certainly possible, it's the mechanical and optical part that is more tricky.
But is it really?
Historically the most expensive part of the Laserdisc player was the laser. This is evident in the lengths my "auto-reversing" player takes to play both sides of the disc automatically. Instead of having two "pickups", it employs gears and motors to move the pickup head from one side of the disc to the other. This makes a lot of racket and takes about 10 seconds. This is also the part of the machine that I had to fix.
Today lasers are incredibly cheap, and while I don't know off-hand exactly what the sensor side of the pickup is, it's hard to imagine it being any piece of electronics that couldn't be had for a few dollars. Perhaps there's some cost or complexity to the optics (lenses, mirrors, etc.) in the pickup head but regardless I can't imagine it's anything that would be so expensive at this time as to warrant the complexity of flipping the entire thing around vs. simply having two heads.
That leaves spinning the disc and scanning the head across it.
Laserdiscs use a few different physical methods of encoding video and data on a disc. The simplest (and coincidentally, highest-quality) is Constant Angular Velocity of CAV. In this mode the disc spins at a constant speed (1800RPM if I remember correctly) and the speed of the pickup head changes in step with the increasing or decreasing diameter of the portion of the disc being read. This mode allows lots of neat features and higher-quality video at the cost of requiring more "sides" to hold a complete film, so a movie that is entirely encoded in CAV will usually require two discs.
The alternative is Constant Linear Velocity (CLV) where the speed of the disc's rotation changes to compensate for the changing diameter of the disc. This mode (sometimes referred to as "Extended Play") makes it possible for most films to fit on a single disc, and if you have a player that can automatically "flip" the disc like mine, you don't have to manually intervene to watch an entire film.
To build a "transport" capable of playing CAV discs is, in my opinion simpler than building one to do CLV, and I prefer the CAV discs anyway (I'm not into Laserdisc for the convenience). Any practical player needs to support both, but I'm fine with the first iteration of my DIY Laserdisc Player only working with CAV.
I think I could build the CAV transport using the same sort of parts and techniques that I've used to build 3D printers. A spindle that spins the disc at a constant speed shouldn't need anything more than a way to clamp the disc to a wheel attached to a motor. It might be possible to use a standard stepper motor for this and use information from the pickup head to create a feedback loop to control the pulse rate to the motor to maintain the right speed, or it might just be simpler to use a beefy brushed/brushless DC motor with an encoder (like the setup I used for the "Blood Elevator" last Halloween). Once the disc is spinning, the pickup head needs to move above the surface in a straight line at a changing velocity, which can certainly be accomplished with a stepper motor and a linear axis akin to those in a 3D printer.
A frame to hold all this together will be needed but this, along with all the individual parts should be printable with a regular 3D printer (so long as it's large enough to print parts for a machine that handles 12" discs).
I think the part that requires the most work is the pickup. I'm going to do some reading to see how these have been made in the past and see what is the most reasonable way to realize one in a DIY context. Designing an optical pickup like this reminds me of something else a friend mentioned to me the other day: there are optical pickups for analog records now as well.
That's interesting.
If I could design a pickup that is capable of reading both Laserdisc "pits and lands" and vinyl record "grooves", the rest of the transport is virtually the same. An LP is essentially CAV encoded so the only real hardware change would be to design a flexible enough clamping mechanism for the drive spindle. Both LP's and Laserdiscs are the same size, so a player so designed could play both.
This is worth spending a little time on...
Jason J. Gullickson, 2026