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Low-Budget Electronics Projects For High School?
SciGuy writes "I am a physics teacher for 9th graders. I really want to teach them modern electronics (something beyond the light bulb and battery). My hope is for a project that: 1) Is fun 2) Teaches about circuits that are relevant to their life. 3) Doesn't rely too heavily on a black box microcontroller. Individual components would probably be better. (I realize that #2 and #3 are probably contradictory. They will already be programming in my class but I want them to understand the circuitry behind modern tech.) 4) It must be as cheap as possible. Yay, public school. Unless some of the parts can be scrounged or found at home, I would probably want to keep the project around $5." What would you build?
Astable multivibrator is a simple circuit, useful (flash lights at high RC values, make sounds at higher values), and teaches the basics of transistor, capacitor and resistor in a practical manner
Have them make a theremin (see the "Similar instruments" section as well). It makes spooky music. Great for a late-October/Halloween project.
You can even make this inter-disciplinary with the music teacher, the English teacher, the history teacher, and the Russian teacher as appropriate.
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
Crystal radio - tons of fun, relevant to kids (music), super cheap. There are kits online, but a little more expensive than your budget ($12 - $15). I'll bet you could get the cost down by buying the raw parts in bulk instead of individual kits.
I'd start with a crystal radio, although there are designs far more compact than the one on Wikipedia. Next, perhaps a simple transistor amplifier (for which you can use the crystal radio as an audio source), then it might be time to move on to the thousand and one projects you can build around a 555 timer chip and some LEDs.
All of these are low power, low cost, and produce a visible or audible result for immediate gratification.
Mal-2
How is the Riemann zeta function like Trump rallies? Both have an endless number of trivial zeros.
its very simple. it gets you results FAST. very little learning curve.
I went from zero (or near zero) to a full running real-world program in a few days (talking to lcd displays, reading from an IR led and handheld AVR remote control, relays, leds, buzzers, etc).
the source code is all out there and its simple. you can find a lot of thru-hole chips that you can 'talk to'. chips are in the $5 range and need only a 50cent ceramic resonator (not even a crystal) and you're up and running.
at this point, anyone exiting school who CANNOT program microcontrollers (not computers, but the smaller controllers) will be left out in the cold. I think the next big thing is small controllers, not 'big' pc systems. get into this early, it will pay back and the ideas/knowledge gained map well to 'pro' level controllers.
--
"It is now safe to switch off your computer."
I did something similar, except we were grab assing and I was vaulting my workbench.
My hand landed on the hot iron with my weight fully, though briefly on the hot iron.
Did you immediately jam the burned flesh into your mouth to cool it?
People still look at me oddly when I tell them that fried human flesh tastes a lot more like sauteed mushrooms than pork.
I agree - the Mimms books are the place to look for basic, cheap yet informative and interesting projects. I used his "Getting started in Electronics" to teach ages 9-12. To make this learning physics rather than just a craft project, it's crucial to teach the basics before doing projects with complicated circuits or chips. I mean at least voltage, current, serial resistance and parallel conductance using the water-flow analogies, and preferably the divided-pressure tank model of the capacitor as well (see Bill Beatty's "Capacitor Complaints" Also read all his articles about "Electricity" or you will be guaranteed to perpetuate misconceptions. Great teaching ideas there.) This is about as much as you are likely to have time for, but very little interesting happens in circuits without semiconductors, so if you can work in the fluid analogies for diodes (check valves) and transistors the kids will benefit.
My personal choice for an educational medium-basic circuit project would be a high-pass and a low-pass single-pole filter (both just a capacitor and a resistor). Use a computer sound card as a signal generator and spectrum analyzer using a free program such as OscilloMeter.
Other good projects would be an H-bridge motor controller (6 transistors) or for something more ambitious a Tilden "nervous net" / BEAM robotic circuit such as a light-tracking head.
"Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery?" - Patrick Henry
1) Is fun
... start with digital on-off operation, then expand to in between voltages, using a potentiometer on its base).
:)
2) Teaches about circuits that are relevant to their life.
3) Doesn't rely too heavily on a black box microcontroller.
4) Individual components would probably be better.
5) I want them to understand the circuitry behind modern tech.
Given these criteria, I would vote, go for a flip-flop. Even the name appeals to kids. Its also historically the basis of a lot of digital electronics design. Its also fun as kids can see the LEDs working and replacing the resistors with potentiometers makes it easily to alter its speed interactively which is always fun for kids to see.
For example...
http://talkingelectronics.com/FreeProjects/5-Projects/Page16.html
But I would say, as you are teaching electronics, before you move onto the flip-flop then first show them a single Transistor with a small switch wired to its base, showing the Transistor can itself act like a switch (use it to control an LED). They need to learn how transistors switch. (You can go onto explain about amplifying later
Both the flip-flop and the switch with a transistor + LED (and a few resistors), all adds up to less than $5 for the lot and you have a few important lessons easily covered in an interesting and visual way.
You can also make the flip-flop switch faster so they can't see the LEDs flashing any more, and then connect up a small cheap speaker, so they can hear it buzzing to show its still flipping. Its a very interactive way for kids to learn electronics, and its cheap and easy to make without even needing a circuit board. Just use tinned wires to form the circuit exactly like its circuit diagram.
There are 10 kinds of people in the world... those who understand binary and those who don't.