Here's a typical (if a little ancient these days!) CD-ROM drive, shown in its "as-removed-from-old-PC" state.
I’ve been interested in aero-modelling for many years. When I heard whispers a while ago that I could make my own high-performance brushless model aircraft motors using parts salvaged from an old floppy disk or CD-ROM/DVD drive, at first I was sceptical.
But after doing a little research, I found that it was indeed possible. It seemed that all that was basically required was to place some so-called “super magnets” inside the motor and to replace the windings to enable higher current flow.
However, as with many projects, when I looked further into it I discovered it wasn’t going to be as straight-forward as I’d imagined.
I would need to find a good source of old drives, locate the required type of neodymium ‘rare earth’ magnets, suitable ball-bearings and would need access to a lathe.
The lathe wouldn’t be a problem because my dad recently gave me his old Emco on permanent loan. Finding the right bearings also wasn’t much of an issue; the types required are used extensively in the likes of model helicopters and cars and are sold in most model shops (and are also widely available online).
The magnet hurdle also proved easy enough to overcome since I soon found a source on the web prepared to ship as many as I wanted and so I promptly sent away for a couple of sets. The next big problem was impatience; the magnets would take a couple of weeks and I wanted be up and running today!
The centre photo shows the controller board removed, revealing the motor in the centre.
Since I own a computer repair company, finding old drives is not a problem; most workshops like ours have a healthy stack of them until periodic clean-outs mean we get to start on a new stack. It is worth ringing around to see what repair shops have available – and avoid those who’ll want to charge you for taking away what is essentially rubbish.
One of the bigger problems you’ll face is that many optical drives don’t use what has become the standard-sized motor; a roughly 25-27mm diameter can/bell with an overall thickness or bell depth of around 6mm. While you can theoretically make your brushless motor from any old drive motor you salvage, many are not particularly suitable for the job, nor are they physically compatible with the standard sizes of available magnets, the majority of which have been designed to fit the 25-27mm motor mentioned above.
I stripped half a dozen old drives to get a couple of decent bells. So get as many old drives as you can while you’re on the scrounge.
If you’re wondering why I didn’t simply work out which make and models of drive contain the right motors and look for them, rather than go through all this rigmarole, it isn’t that simple.
You can take two outwardly-indistinguishable models and find they have significantly different mechanisms. The chipset and firmware might be the same but the cradle, motor and laser assemblies vary greatly from drive to drive, even within supposedly “identical” models.