Toys for Kids: An Electromagnet

Although I've never been told I lack any measure of self-esteem, at the same time I don't think (I hope) I boast excessively about my accomplishments, whatever they may be. There is one area, however, where I will happily say with confidence I excelled; manually (by hand) winding electromagnets, transformers, solenoids, chokes, you name it. Of course with the proliferation of the internet there's a good chance that if you googled hard enough you would find someone who's devoted their entire lives, family and children to winding coils, but if you're talking about "normal" people, and I say normal with great hesitance since we are after all discussing me, I don't think there's anyone else out there who has so perfected the art of winding copper wire.

I haven't lived at home for about 10 years. My electronics bench at home is more or less how I left it when I departed for college. In the drawer I still have spools of magnet wire, from #18 to #30.

Underneath the desk I have a 15 pound spool of #36 magnet wire, for winding induction coils, as well as some copper drain pipe for tesla coil primaries.

Just a glance to the shelf on the left reveals more coils (with a backdrop, embarassingly enough, of my Neo-Geo game collection). This is just a small collection; I have wound hundreds of coils, most I just threw out or unwound to use the wire for something else.

Although all the coils you see are linear--with exception of winding coils on a horseshoe, of all things--I've made conical, pancake, toroidal, you name it. I have special bobbins of various sizes depending on the size of the toroidal core I'm using. At this point I think my parents, when they saw me doing this, secretly wished I just liked Nintendo like everyone else.

My most impressive coil was to wind an induction coil from #35 magnet wire, by hand, on a former 8" long by 3.5" wide. Every day for 3 months I would come home from school (I was in 3rd grade or something) and wind an even layer, wrap with a sheet of wax paper, dip it in varnish, and wind another layer. I started with a 5 pound spool of wire, and was almost empty when I finished. I literally wound miles upon miles of perfect, laminar windings. And then once I finished, the input lead to the first layer broke off. I didn't even cry, I just started over.

My favorite coil of all time is this one. I wound it when I was 8, it is made from a bolt, two fiber washers, and exactly 1/4 pound of #26 wire. Even today I think the windings aren't half bad.

Anyway, so you get the picture. Faucet's leaking? Call a plumber. Need to off someone? Hire a hitman. Need a high-performance, aesthetically-pleasing coil of wire, and some asshat to wax poetic about it? I'm your man.

See the thing is, I'm not convinced that I'm the only one with this problem. I think, and this is a totally biased perspective, that lots of little kids would have fun playing with magnets, coils, batteries, just the same way I did. They just need someone to start them off. Eccomi qui! So I've decided to start a section of the blog devoted to small toys, projects and experiments with the little ones in mind. If this turns out to be a total disaster, keep in mind that I was an odd little one.

The first project I have in mind, if you haven't already gotten the sense, is to make an electromagnet. So great, go get some wire, bolt, and be done with it. Not quite so simple. See, back in the day, kits and experiments for kids like HeathKit were very close to the "real thing".

A -> ? -> ? -> ? -> B... oh hell. You want me to build what?

You got the raw parts, some excellent instructions, and were expected to have the manual dexterity, engineering insight, and experience to correctly assemble a  complex system. In a sense, they expected a very high level of expertise and maturity out of the hobbyist. For the advanced experimenter, it is nice to be working on things that are challenging but with just enough guidance to enable one to build a device that would be otherwise unattainable; for the beginning hobbyist, it is simply too daunting and most likely would end in frustration and failure.

These days, it's the total opposite. Electronic kits dumb everything down to a sequence of manual operations with zero insight, learning, or even fun. In short, you might as well be pressing buttons on a video game. Take for example, "Snap Circuits":

Wait so what you're saying is, everytime I fasten my pants the wheel will turn and the light will go on?

On that board are R's, C's, L's, and even a trimcap. But all the kid is going to know is that "when I put the white block, green block and one of the yellow blocks together and connect it to the lower right portion of the board near the batteries, some hum comes out of the red box." Where's the learning there? Making a young kid strip, tin, and solder wires is a bit too much to ask, but snapping circuit elements together is banal. Somewhere between these two extremes is a happy medium.  Here's my list of good and bad:

GOOD

• Mechanically reinforced wires and leads.
• Durable, modular connectors like banana plugs, alligator clips, etc. along with bare wire leads.
• Wires! Lots of them, different colors, sizes, etc.
• The possibility of irreversible damage, in controlled amounts. Too many kits make sure devices are more or less electrically bulletproof. This is what we professionals do because we know that although we take every precaution, sometimes accidents happen, and we don't want to destroy our work. But kids haven't learned good safety practices, and should therefore be exposed to the idea that sometimes mistakes can't be undone. I'm not talking about sticking metal forks into every power outlet and saying, "Don't touch, it's dangerous" rather say a lightbulb with no ballast resistor with the warning "do not apply more than 3V."

BAD

• Rigid, lego-like construction; limits configuration options, gives the wrong idea (that electricity flows in fixed paths).
• Too much abstraction; inner workings should be exposed as much as possible, even if it compromises durability a bit (after all, learning to be careful is a big lesson we all need to learn).
• Exposing too much at once. Hours of fun can be had with a lightbulb, a battery, paperclips and some wire. Are a potentiometer and trimcap really necessary? Never introduce anything that can't be explained, at least in a basic intuitive manner.

Following these basic tenants, I proceed to make a toy electromagnet. First, you're going to need some #26 magnet wire, packing tape, a 3/8x3" bolt (threading doesn't matter) washers and nuts.

The first task is to make an electrically insulated former, on which the windings will be wound. To do this, you first need to wrap a layer or two of packing tape on the bolt, as well as put a layer on each inside surface of the washers. This can be trimmed with a razor blade.

Winding begins by affixing one end securely, and winding one laminar layer atop the previous.

When winding coils, it is important to rotate the former rather than winding by wrapping the wire around the stationary former. This is because the latter will introduce twisted tension into the wire, which will make your windings uneven. If you're a pro at this, you can wind each layer atop the previous without putting an insulating layer in between; otherwise, a single layer of tape between each layer will provide some mechanical stability (and also a safety net, in case you drop the coil only the current layer will unwind). When the topmost layer is reached, wrap the windings in several layers of clear tape.

Now you've got to mechanically reinforce the leads to the electromagnet, because the inner wire is especially vulnerable to breaking off, and it if does, all is lost. To do this, first you have to make a physically strong anchor for the leads, so that if you pull the leads from the electromagnet it will not put force on the magnet wire windings.

Next we employ a common technique called "potting" whereby the entire wiring is enclosed in a heat-shrink tube, and all the air inside is replaced with epoxy. This is done for many reasons: waterproofing, vibration damping, physical durability, to name a few. Here is the finished result:

So there it is: a fairly kid-proof toy that is still visibly electromechanical.