Kit 18: Wind-Powered Generator, 2300 yen (about $23 USD). Back in the world of electron flow, we have a small wind-powered electrical generator, which is good for primarily running a night light, if you need a wind-powered night light.
Most people have at least a vague understanding of how DC motors work. Wrap wire around a core, and when you connect the wire to a battery, you make an electromagnet. Have real magnets located in a housing and put the coil on a spindle, and when the coil is connected to power it gets attracted to a magnet, but then the connection gets cut. The momentum of the turning spindle brings the spindle back into contact with the current and the process repeats. In essence. Real motors are more sophisticated than that, but this is the way kit #21, the DC car, works.
Interestingly, the reverse process also works. Pass a magnet near a coil of wire and electricity gets produced through the coil. Put some magnets in a housing, and the coil back on the spindle, but now attach a prop blade to the spindle and when the wind turns the prop, the motor morphs into an electric generator. The Gakken kit produces about 1.5V at normal wind speeds (maybe 5-10 MPH), just enough to make an LED turn on. The kit supplies 1 red LED, but you can use other colors if you like (with the caveat that LEDs of other colors usually have higher turn-on voltages, so the wind will need to be stronger for them).
This is a very simple kit. I was hoping/dreading that I’d have to wrap the wire to make the coil, but it’s provided as a standard commercial AC motor. 15 parts, and a suggested 20 minute assembly time. It took me about 20 minutes, too, because I wanted to tape the prop fins on the backing fingers “just right”. Applying the double-sided tape to the prop fins and backing fingers took the most time. Really, it’s just a motor wired to an LED inside a housing intended to mount onto a soda bottle. There’s a little plastic piece underneath the housing that lets you restrict the housing rotation to just a 90-degree swing, or allow a full 360-degree rotation. Suggested mods include decorating the prop fins, mounting the generator on a small child or Christmas tree, connecting the motor to a music chip from a greeting card, and building a bigger coil. Mounting suggestions include the soda bottle or a PVC pipe, or taking the soda bottle and cutting it up to make a support for taping it to a fence railing.
The mook is “green”. At least half of the articles concern alternative energy sources (solar panels, super-massive wind generators, geothermal and beamed energy); the theory behind wind-powered generators; the mechanisms behind green house gas production; and, projected global warming temperature maps. Other articles include suggestions for housings for Gakken’s speaker kit; theory of operations for Gakken’s vacuum tube amplifier (plus a photo showing it connected to the theremin kit); photos of a “baka-robo” (silly robot) contest; and a short story with the editor learning how to weld his own steel chair.
If you want to learn how to make your own, larger, wind-powered generator, this is a great kit to start from. If you want a wind-powered night light, GET THIS KIT. Otherwise, this kit doesn’t do much. You need a pretty stiff wind for it to generate enough electricity to turn the LED on. It’s an AC motor, so the LED only stays lit for half of the time. I did test it by holding the generator in front of the air conditioner, and the LED does light up within about a foot of the air vent, but there’s a very noticeable flicker; ideal for attracting UFOs.