Calling all electrical engineers
 

So I want to build this thing.

It's just a flat, rotating, vertical disk on some sort of basic stand (imagine a microphone stand,) with a controller box that has 3 features: on/off, bidirectional switch (that is, in can spin either clockwise or counter-clockwise,) and continuous speed adjustment.

I'm pretty sure the first step is a Continuous Rotation Servo. But then it gets into microcontrollers, and I'm out of my depth.

Assuming I could solder or get a friend to solder for me, am I smart enough to make this thing if I had suitable instructions? It seems like it ought to be pretty easy, with some basic parts from RadioShack.

Can you just take a cheap remote control car apart and mount your disk to one of the wheels and use the existing controls? How big does it have to be? How fast does it have to spin?

No point reinventing the wheel.

Our kids have these Morphibians, and their wheels go forward and reverse with existing controls.

edit: I missed the part about continuous speed adjustment. Not sure how continuous the speed adjustment is on these. A drill will do all that though.

That is an interesting idea. It should spin relatively slowly, the disc is lightweight and about 2 feet across. Ideally I wouldn't have to hold down the controller with my thumb the whole time it's rotating, but I could probably work up something that would hold it in place. Though it would also be better if it ran on AC instead of batteries.

how long does it have to spin?

What about a bicycle wheel and spin it by hand like wheel of fortune?

ceiling fans spin both directions, run on AC, and have three speeds in each direction.

I just gave away one I replaced. check goodwill.

you could used the motor to spin a wheel that touches the hub of the other disc if the speed is not slow enough.

like oO. when the little o is spinning clockwise, the big O will be spinning counterclockwise. the little o can spin fast and the big O will spin more slowly.

A basic cordless screwdriver does everything you need - except the remote control bit! You need a cordless screwdriver and a broom handle.

...or adapt this:

http://imakeprojects.com/Projects/screwdriver-rc-car/

You guys are awesome, I knew you'd have some good ideas.

It seems like you could work some old turntable parts into this.

Or, you could just spend twelve bucks and buy the thing.

What do you want it for?

yeah! what in the hell are you making?

some kind of centrifugal dehydrator? a child distracter? a halloween decoration?

My guess is that it's some kind of murder weapon.

Spinning Uranium? :eyebrow:

Hypnosis is not a hobby. Or is that electrical wiring? I can never keep that straight.

It's a vision therapy thing. The disc is actually a pegboard, and it has various overlapping geometric shapes drawn along the holes. The user (i.e. Minifobette) sits close to it and outlines shapes with pegs one at a time while it spins. I've tried it myself and it's a fairly intense hand-eye coordination effort, depending on how fast it's spinning, and of course it's important to change up the speed and direction occasionally to keep the workout going.

Of all the exercises she's been doing at home and in the office, this machine is by far her favorite, and it's been getting the best results as far as increased tracking control with her eyes. But of course the therapeutic one is patented and costs $600. Ridiculous. I feel sure I could make one for home use for less than $50, and the optometrist's office has even hinted that if I do make a working one, they'll buy it off me after Minifobette doesn't need it anymore.

Can you direct us to a photo of one? It sounds really simple to build.

eta: Is it this?

you could pick up an inexpensive electric drill, mount it to a wooden base, and chuck a bolt into it that would hold the disk. Most VS drills have a trigger lock. You could also plug the drill into a dimmer and use that to adjust your speed.

Depending on how tight you bolted the disk, that connection could act as a sort of clutch.

Any small, variable speed motor would do. I'm sure you cold pick up a turntable at goodwill and use that. Belt drive would allow for the disk to slip and would allow you to gear down or up.

Yep, that's the one.

I definitely like the drill idea, since they have rechargeable batteries.

My inner asshole came out and said to use a Dremel. 35,000 RPM!!

Look here for slower models to work her up to the big boy.

This motor looks promising.
http://www.amazon.com/Wondermotor-Va...lectric+Motors

It comes with the speed controller knob attached to a foot long wire, and it's reversible depending on how you wire it. But you could add a switch to make it reversible at the flip of a switch.

At a max speed of 50 RPM it seems perfect. You wouldn't be able to follow a spinning disk with your eye any faster than that. If you have an old turntable, you should follow that with your eye to see what 45RPM looks like.

It's a little expensive, so if you got it and the variable speed wasn't as smooth as you wanted, you would be out $90. But it has some kind of mounting holes, which is nice, and it's fairly powerful, so you wouldn't be taxing it too much. They suggest a $17 power supply that goes with it. With that power supply, you would plug it into the wall.

I don't know enough about electronics to know what that controller is like. I don't know what pulse width modulation means. But I'm guessing you turn the knob to turn it on and then turn it more to make it go faster, up to 50 RPM. It's got a 10 MM drive shaft (1 cm) which is nice and big to work with. Many small motors have these little drive shafts, and how are you going to mount a big disk to those?

That looks perfect glatt, thanks!

http://www.nielsendesigndiscgrinder....c_Grinder.html

Instead of attaching abrasives you could attach just about anything else (like a small child, given a big enough motor).

I think 1800 rpm is a bit much for the eye to follow... :)

Clodfobble

you're a big cooker person. do you own a kitchenaid stand mixer?

I do, but I don't exactly want to dismantle it...

!!!
well I don't but twil does. I was monkeying around with hers while she was mixing the pumpkin pie fillling and I discovered the little chrome cover that hides the front PTO. that's the power take off for accessories that don't use the bowl. I noticed that it has what looks like a half inch square drive. and I noticed that the whole drive/head tilts upward. and I noticed that the speed control is adjustable and looks like it starts pretty slow.

could this be the drive unit for your Clod-traption?

I'll have to check when I get home (at the in-laws' for Thanksgiving right now,) but I think the head doesn't tilt all the way back, just 45 degrees or so. I could maybe make her stand beneath it and look up, though. To be honest I've lost most of my steam for the project though, they've already moved on to more advanced exercises in therapy. They did a reevaluation with the doctor last week to see how she's doing, and everything was greatly improved. It's cool to watch her picking out 3D stereogram pictures that she simply could not see 10 weeks ago.

"greatly improved"

what a great problem to have!

enjoy your company and your holiday. we'll continue later. happy thanksgiving