Useful Toy Motors

PaPa Peng wrote the following:

I have a couple of old portable CD players - the kind used like the Walkman, but plays a full sized music CD. It is about 3/4" thick and about 3/4" wider in diameter than a CD. I was wondering if I can use the drive motor in it for something. I don't know what the speed of this particular motor is but it has to spin in the thousands of RPMs. I wonder if it could take some gearing down without losing too much power, like for static model plane props (not RC). If so, I can power two single engine planes or one twin engine plane. Maybe I'd have to secure the planes down to a base lest it tries to take off. :-)

CD drives rotate up to about 200 rpm max, the speed changes as the head moves in and out on the surface of the disc. I have an old Airfix Rotodyne in the stash that'd look rather good with all three props turning.

Regards

Mike

As for spinning props - it should spin anything that presents a mechanical load equal to or less than the weight of a motionless CD, huh. ;-)

I've never cracked one open but I would imagine the CD player is belt driven, and probably not at 1:1. So you might have some speed reduction going on already. I know next to nothing about electro, but IIRC resistors and resistance circuits are a basic means of introducing speed control into a motor circuit. I'm sure there are slicker ways and none of them should cost a lot of $$$.

WmB

WmB wrote the following:

I cracked one open. It was an Emerson portable CD player driven by 2 AA batteries. No belts. There are two motors in it, a direct one to drive the CD turntable, and the other is geared down to advance the laser across the CD. The round motor is a direct drive to spin the CD, and the cylinder motor to advance the laser with reduction gears. Pic here

You'd be wrong. All the CD drives I've seen have a direct drive pancake motor in the middle. The downside is, you'd need the controller as well, CD's and DVD's spin at different rates depending on where the read head is on the disk. The motor controller is going to be a small IC though, not much of a weight penalty.

The head positioning motor is a small stepper motor, and only provides coarse positioning, the fine positioning is done by a moveable mirror in the read/write head.

This is probably what you are looking for.

motors

[Here we go; these fascinating compact brushless motors are a hobbyists' and tinkerers' delight. The base structure is the platter motor from a dismantled computer cd-rom drive. Easily and cheaply available, dead or old drives can be begged from computer shops or friends, I even bought one once! At the time of writing I have one working reliably in my Moth microheli. It is powerful and weighs only 24grams. You will need a brushless, sensorless motor controller to drive one, I've used an old Jeti06, Castle Creations Phoenix 10, and a Tsunami 10 successfully.]

Do a google search for outrunner motors and you will get more hits. If you need small rare earth magnets Radio Shack has a blister pack of four (?)pill sized magnets for two bucks. Also google for suppliers if you need larger numbers of rare earth magnets or of a different shape and size.

I'll pass up on this project (outrunner motors) myself.

As I said earlier, I took the CD player apart. I just now put two AA batteries in series and added wires and both motors spun at full RPM. Not much torque and even less sound. I could see the gear turning on the shaft of the one motor, but I had to put the CD spool on the pancake motor shaft to see that it was spinning. Hint: If you don't have a battery compartment to complete a circuit ( I didn't ), put the two batteries + to - end and place two strips of plastic tape long enough to cover almost the full length of both batteries on each side of the batteries stretching the tape so that when they contract they will hold the battery poles together. The add extra lengths of wire, if necessary, to reach the motor wires.

On Mar 3, 8:18=A0am, willshak wrote: >I wonder if it could take some gearing down without losing too much power,

You'll be better off using the miniature cellphone vibrator motor.

To remove the eccentric vibrator weight clamp the weight on a vise and punch out the motor shaft using a broken twist drill bit of the same diameter or nake a punch pin from piano wire. I got a pack of 10 vibrator motors for $10 from a surplus store. They never restocked them.

You can make your own battery pack that can fit inside the fuselage or engine nacelle. Use the blister pack the button cells came in. Roll three or more button cells (three cells needed for LED lights) inside a paper cylinder to form a battery pile. Leave the cylinder ends open. The molded plastic blister cup cut from the packaging is used as the end cap for the paper cylinder battery. Tape shut. If you want to solder the wire leads onto the battery be careful that you don't overheat the cell. The overheated chemicals can explode. It won't injure you but I wasn't happy breathing in the chemical fumes. Or otherwise use an elastic band to apply contact pressure on the wire leads.

If using AA or AAA cells leave them inside the blister pack. Melt holes in the blister plastic so that you can solder the wire leads onto the exposed cell anode and cathode. There, you have a neat home made battery pack for $1. Discard when the battery runs down.

I stand corrected - well, seated. Must be thinking of something else - floppy drives mebbe? PC repairs are the only electro thing I've ever done with any regularity or frequency (long, long time ago) and I know I saw a lot of belt driven drives somewhere.

Anyway you slice it, the CD player motor sounds like more trouble than its worth (for an electro clueless like myself) when you can order up the specfic motor and controller to suit your application with regards to the mechanical load and torque requirements.

But if one is smart with those things I suppose its worth a shot.

WmB

[pinky finger to corner of mouth] "Yes... laaaaaaaaaaaazzzzzzzzzzzzers..."

I'm interested!

WmB