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Electronics Projects for 12-Year-Olds?
nepheles asks: "I've recently been asked to teach some electronics classes for a group of 12-year-olds. They're all new to it. Electronics always seemed boring in school, so for them, I've been looking at hands-on projects: I've considered making basic motors, steady-hand games, and Morse-code communication systems. What experiments have you seen in electronics that amazed you, and that could be recreated in the classroom? What cool things have you made that would be simple enough for a kid to do? At a meta level, how would you like to have been taught electronics?"
If you show them anything with AC or that has any cyclic voltage variation, show it to them on an oscilloscope.... It's much easier to a 12yo if they can visualise what is going on.
However basic electronics is the stuff that 12yo kids get - show them the foundations...
The wire-wound rheostat.
The two-pencil carbon arc.
Heating nichrome wire to make a poor filament.
Build a battery in a beaker.
Hand-wind a motor and build it on plywood with
wire.
Electromagnet locking to a piece of metal.
Morse key, with a solenoid recording the results.
You want to show them something so that the building block *stays* in their mind....
If the idea is simple enough, it stays with them forever.
GrpA
Enjoy science fiction? "Turing Evolved" - AI, Mecha, Androids and rail-gun battles. What more could you want?
As technology changes, we start off learning about it at a higher level. Nobody learns to use electron tubes these days, though they are used in some applications.
Take a similar approach. Provide some basic understanding of the transistor, but don't make a circuit that simply blinks. Instead set them up about 10 years behind the curve rather than 20: throw together a small microcontroller board and a breadboard with some components. Maybe just give them a bare microcontroller to insert into the board.
Start with a few basic circuits, light an LED, amplify a light or sound source, make a touch sensor. Then get them to write a small program for the microcontroller, to blink a light. After that, try something a little more interactive like a who-pressed-the-button-first game.
A mess of transistors and wires isn't inspiring, and most of the kids won't have any idea how to come up with useful circuits on their own. But when they realize how much they can do with a microcontroller, watch their eyes light up. Well, maybe some of the geekier ones will. But use the microcontroller as the core, and introduce analog concepts as they relate, for example doing R/C calculations for a smooth PWM signal.
A single programmable component can often replace or exceed the function of dozens of discrete components. That's where things are heading these days, though analog designers are still needed. I just think you should introduce some technology of our generation so they won't blow off electronics as a lot of work to get a result a thousand times less exciting than what their cell phone can do.
There are all kinds of things you can make from a disposable camera flash. You can make a strobe light by using a diac, neon lamps, or a triac and an external circuit connected across the shutter contacts (use a D cell instead of the AA so it charges faster) or make a paper clip shooter by connecting a coil in series with the flash lamp. Wrap the coil around a tube of some sort and put a paper clip just behind the coil. To fire it you will also need a *WELL INSULATED* push button wired to the shutter contacts. When the button is pushed, the flash lamp will begin to conduct and allow current to flow through the coil. I saw a similar device in an electronics class that was made from six disposable camera flash units wired in parallel, and connected to a flat coil on top of a clear box. There was a metal ring and a ping-pong ball on top of the coil, and when the cameras were discharged through the coil it was able to shoot the ping-pong ball about 50 feet vertically. (It used an SCR instead of the flash lamp as the switch.) Also you can get the cameras for free from some photo developing places and they only need 1 "AA" battery to work. The only problem is obviously the high voltage - if you are going to have 12 year olds messing with these things you need to make sure the cameras are insulated well before you let anyone turn on the power, and that they are discharged before anyone starts wiring anything up.
Make loud noises
Give off heat or flames
Give of bright light
move on it's own
be capable of irritating your friends at lunch
So, overloading exploding LED capacitors are the answer!
so yeah, making your own motors would work, building a race car with a pair of small motors and a headlight with a wired remote to start/stop, homebuilt radio, a small generator to light a lightbulb, etc.
Lastly, be sure it's durable, cause they will be dropped and abused a lot on the way home to show mom and dad.
SAILING MISHAP
but Radio Shack's electronic project kits were the key for me. When my dad showed me how to light a light bulb with a battery i immediately had him take me to radio shack and get me one.
... then, when i was about 10, i was working on my project kits and suddenly it hit me... "dude there are girls out there. go get one!" so I went outside, hopped on my bike, rode down the *sidewalk*, and was smashed by a car coming out of the alley at 35mph. i was thrown right into the street, skipping the part of the alley between the sidewalk and the street, some 20 feet away. no broken bones but a concussion and a broken eardrum.
...
I spent the next 4 years doing nothing but tinkering with my project kits. I made radios, motion detectors, calculators, wind generators... i wound up fixing TVs and walkman radios, and game consoles for friends.
i kept off the electronic project kits but i never did get a girlfriend until i was 18.
my lesson to you - stay away from electronics, and keep the kids away too. I mean it.
this is a true story, by the way. all too true. I still can't hear things like digital watches out of my left ear