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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
When I was middle-school age, I had a *great time* with these kits sold by Radio Shack. They were basically a bunch of cheap electronic components fixed on some sort of board, with connections, and a bunch of wires you could use to connect the components together into different circuits. It even came with a book with like 40 or 100 (I don't remember the number, really) different circuits 'plans' for simple types of things you could do with the kit and discussions about how the circuits worked.
They cost like $10 or $20 back then (probably be $30 or $40 now, not sure though).
I would *highly* recommend looking into something like this. They are maybe a bit more expensive than you discussed, but they are re-usable and allow you to create lots of different things. Heck, you could maybe even figure out how to use multiples of the kits and maybe a few additional components to create something a bit more impressive to demonstrate to the class how larger electronics systems are created by configuring each kit into a specific type of circuit, then joining the kits together (that is, each kit becomes one 'components' of a larger system, maybe).
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.
SIMPLE, LOW-COST ELECTRONICS PROJECTS
http://www.elsevier.com/wps/find/bookdescription.cws_home/677563/description#description
"Kill 'em all and let Root sort 'em out"
I'd recommend a simple oscillator project. You can use it to either flash two LEDs or create tones for a speaker. It covers the use of transistors, resistors, and capacitors. The cost should be very low, and the project can be put together without solder in several different ways. Here is one article with an example.
http://www.arrl.org/news/features/2003/10/30/1/
I don't think soldering irons are a requirement for this idea. Breadboards, or even springboards, would be much more appropriate, I think. Cost per student goes up, but overhead goes down.
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.
I just taught a unit on electronics. We used breadboards and the 555 ic to build optical theremins. I have the entire curriculum done. contact me through /.
$5 won't buy you much if you buy the components individually. You need to buy them in lots -- in which case you can afford a lot more room to experiment. Also, some equipment can be re-used, like breadboards, multi-meters, etc. When considering the project's costs, don't neglect economy of scale. It might be cheaper for everyone to simply have a "lab fee" and buy enough to last a few years.
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Both items are familiar to the students, so they can be tricked into learning something new. Have them connect light bulbs in series, then in parallel, to see how the brightness changes. Add batteries in series. Add batteries in parallel. Once they are familiar, have them connect ammeters and voltmeters for numerical interpretation. This would give them a solid intuitive feel for how circuits work.
I would not teach them anything about transistors and capacitors until later, because that would require too many advanced concepts. Make sure the students do not feel overwhelmed by the material. If the students feel confident about what they are doing, ie. it makes sense that adding in more batteries makes it brighter, then they will be inquisitive to learn more, and confident enough to set out on their own.
You didnt have a shop class in high school? I took metal shop and got to play with welding torches. That had a much higher potential for getting seriously hurt than a soldering iron.
WTB [sig], PST!!!
another option, and I just mentioned him on another story the other day... is take a look at the old forest M Mims III books. They are the books that they used to sell for a couple bucks at radioshack. You can still get them from his website, or a few other places (saw them at Fry's the other day) although they cost a few dollars more now. I started reading his books in the 4th grade and I have worked and played with electronics ever since. Each of his books have schematics (and a guide on how to read them) for many projects which can be built for a few dollars on a breadboard. I would suggest looking at something with a simple linear analog IC like a 555 or 556 timer.
If you go to jameco.com you can get component grab bags, or my favorite are the component kits. For example the resistor kit has a selection of common values and a nice plastic storage thing that keeps them nice and neat. Give every student a few LEDs from a grab bag, a 555 timer chip, a battery, some jumper wire, a handful of capacitors and resistors from a couple of component kits, and the schematics to make a simple LED flasher. Then the different students will have different values of resistors and capacitors, and will get different results. Then you can time the flashing of each students project and chart the values of resistor, capacitor, and time. Explaining simple RC circuitry is a good place to start teaching somebody electronics.
The Mims books also get into digital, you could buy some simple nand gate chips and show the students all the different ways to use them, use simple push buttons for input and LEDs for output to save money. It may not be super exciting, but you could build an inventory over a couple years to do something really cool. Use TTL chips, not CMOS because the students will ruin CMOS with ESD. The possibilities are really endless. Any students who really get excited can buy a handful of parts online and build all sorts of neat stuff from those books. There are circuits for opto communications devices, a shortwave radio, a break beam sensor, you name it, its in there.
Obama is a twitter sock puppet
I am working on some similar projects for 11-12th graders though my budget is more in the $10 per student range. There are challenges with doing this without (a) soldering - and the risks, and (b) lead exposure. Anything intended for kids younger than 13 needs to be Pb-free to meet CPSC guidelines and avoid liability issues. For 9th graders you might need to check ASTM regs also regarding choking, entanglement, etc. It's a bit of a bear and it becomes harder the younger the kids get. I am using largely recycled components from junk cellphones and other sources (TDMA cellphones in particular are available dirt cheap and have lots of interesting projects) - http://www.larwe.com/technical/2260lcd.html documents some of my reverse-engineering though it doesn't explain why I'm doing it). A couple of interesting projects that can be made without soldering (just twisting wires) - Use a Hall effect sensor or reed switch, in combination with a light (LED, bulb, whatever) and a handful of small magnets to demonstrate making a "recording". Glue the magnets onto a strip of paper, or just use a piece of tape sticky-side up. Pull the tape past the sensor and watch the bits as they're read out on the bulb. Works best if you color say all the north poles red, so they can work out what is 0 and what is 1. - Make a light-following robot with two pager motors. There are a load of designs around, this one is not the simplest but is illustrative http://www.geocities.com/SouthBeach/6897/photovore.html If you want to liaise further, feel free to contact me using that website.
Why is this tagged 'domyjobforme'? There's a negative connotation there.
This is an (awesome sounding) teacher looking for suggestions on how to expose kids to something worthwhile.
You aren't doing his job for him until you're working for his salary, on his budget, and care enough about your students to step outside the curriculum once in a while for education's sake.
What is this, the Hipster Olympics? Do we win by looking down our noses at people?
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."
There are so many things you can do with an 555 IC that it's not even funny. Digikey has them for 44 cents per unit here. With a handful of descrete components you can create everything from flip flops (with 2 555 ICs) to oscillators to time delay circuits. (some example circuits.)
I suspect with a handful of 555 ICs, descrete circuits, ICs and switches (or just touch wires together), you can easily create a whole host of illustrative experiments that show the idea behind modern gate circuits. And I'm sure you can easily do it all for a few dollars worth of components, though unfortunately breadboards can be quite expensive. (Around $8 for a small breadboard through Digikey, though you may be able to find cheaper.)
Soldering has no place in a public school.
Yeah. No one should be learning useful skills in public school!!!
Someone will burn themself, and sue.
As others have mentioned, do you also propose to ban welding in shop class? Alcohol burners in chemistry? Sheesh, you can get a rug burn if you fall down in basketweaving class. A little pain is good for you; pain is a sign of stupidity leaving your body. If nothing else, you learn to be careful with potentially dangerous tools. That is a (TM) Good Thing. Just accept the fact that you can't even get out of bed without accepting some risk and get over it. :rolleyes:
Someone will sue because of exposure to hazardous materials...
RoHS. Use lead-free solder. Problem solved. Besides, I've soldered with leaded solder since I was about tennnnnnn, and I'm just fine I'm just fine.
...or some government agency will get involved.
It's public school -- methinks that, by definition, a government agency is already involved.
MCSE? No, sir...I don't do Windows. Yes, I am an idealist. What's your point?
Make all those 'dead' batteries run little torches:
http://www.emanator.demon.co.uk/bigclive/joule.htm
No sig today...
Don't use anything that will automate the work. Make the students do everything at a low-level if they are to learn anything. This is my opinion, only.
Start with basic theory - digital logic and Karnaugh Maps. Introduce the clock and how it can manipulate the states of a digital logic device. Then pick something simple - like a stoplight controller, for example. And then create it.
Using the stop light controller as an example, you have a number of states that can be easily reduced with Karnaugh. Using a basic breadboard and logic gates (not more than a few bucks per head in bulk), the students should be able to design and build the stoplight controller. Use LEDs for a direct representation of the stoplights.
Extra Credit: put in a cross-walk button, corresponding states, Karnaugh maps, gates and LEDs.
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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
If you want to teach PHYSICS, I recommend against digital circuits. There is much more Physics to learn from Analog(ue) circuit design and implementation. Indeed the first circuit I ever built was an AM radio reciever, according to instructions found on my school Physics textbook: "Physics for Today and Tomorrow" by Tom Duncan (IMHO the best Physics book ever) The component count is very low, about 10 components... the most expensive and difficult to find? of which are the the ferrite core and the variable capacitor. An AM radio receiver can be used to teach about electromagnetism, resonance, electronics, etc. Students wishing to go that extra mile can attempt to also build an AM transmitter (this can be even easier to build.)
- "They misunderestimated me."
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.