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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?
http://bwrc.eecs.berkeley.edu/Classes/icbook/SPICE/
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
The only thing I can think of is to have an additional fee for this project, unless you're looking at something like the light bulb that you were referencing. The other key thing is, do you have enough irons to go around. Not everyone solders or even knows how to at all, so you need to make sure that you have enough soldering irons for the students either to work individually or as small groups.
"Don't meddle in the affairs of a patent dragon, for thou art tasty and good with ketchup." ~ohcrapitssteve
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).
A nand gate would be good to build with transistors since those are used in RAM and modern circuits. Also power supplies can't go wrong either (for charging a cell phone or something.)
-What have you contributed lately?
I would do something with a 555 timer, there are a ton of applications and although you may consider it a 'microcontroller' all of the support electronics (pots, leds, resistors) will be instructive. Throw in an SCR to drive a high watt light bulb.
love is just extroverted narcissism
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/
Virtually anything digital will have one or more oscillators in it. The kiddies might well have fun with a 555 or discrete based oscillator. All the components(with LED or nasty little speaker to output the result, and a potentiometer or resistor selection for playing with frequency) are dirt cheap in even modest quantities and the theory of operation is a step above bulb 'n battery without being super tricky.
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.
Consider simple transistor circuits. There is a book out there called The Encyclopedia of Electronic Circuits that has hundreds of simple circuits.
Look at circuit design software like AutoTrax (Kovac Software). He has some great education pricing. They can design circuits, run SPICE analysis and then build them and verify the results.
Model Railroading offers many opportunities to build things that have an immediate purpose. Blinking LED projects, sound, electronically controlled motors for crossings.
I built a small N scale project that needed three voltages; 3, 12 and variable 12 volts. I used one of those old laptop bricks and a few voltage regulators, diodes, caps and resistors and I was all set. BTW, I knew nothing about electronics, just kept reading as much as I could and it started to make sense. It really helped to mix something I knew ( modeling ) with something new ( electronics ) with a simple goal, make some trains run.
As for cheap, most of the parts were free through scavenging and some were bought from Digi Key.
I woudl imagine with cost being the driving factor you are very limited. As most modern circuits would require a resonable power supply, ocilloscope, plus components. This being said since you sound like you already have computers look into getting a simulation program that will allow you to build circuits virtually and test them. just a though.
(random google search)
http://www.electronickits.com/kit/complete/kita/ck800.htm
At over $40 a pop for a basic model from a kit, this may have to be a group project.
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
A couple of photo-resistors and transistors to drive simple gear motors (http://www.sparkfun.com/commerce/product_info.php?products_id=319). Wire everything to a proto-board for easy rewiring and reconfiguration. Hook the photo cells to drive the motors on the same side of the bot (R-R, L-L) for light avoiding behavior, and cross the wires (R-L, L-R) for light seeking. Bumpers could also be added which kills power to the motors with only switches and no other components.
This would probably run more like $20 but would get a base ready if they wanted to pursue microcontroller based robotics in the future. Also things that move have a tendency to grab kids attention.
A-stable multi-vibrator.
Attach an of LED and bam, cheap way to teach rudimentary capacitor/transistor theory.
the 555 timer is a great IC and there's lots of cool things you can do with it.
That and a few proto boards would make a fun project
... I would suggest them building a bristle bot! http://www.evilmadscientist.com/article.php/bristlebot
Hardware random number generator using a couple of resistors, a potentiometer, and a zener diode. For additional points, use a comparator to amplify the noise. You can then talk about the physics of electron transfer across the diode junction and thermal agitation to describe why the noise occurs.
Another interesting project is a feedback controller that levitates a ball hanging below an electro-magnet. You use an LED and a phototransistor to set up a circuit that tries to keep the reflected light intensity constant, which makes the steel ball hang a certain small distance below the magnet.
Neither of these is too terribly expensive, and both have physics content, but neither is what I'd call "modern". Almost all of modern electronics involves digital integrated circuits.
((lambda (x) (x x)) (lambda (x) (x x))) http://www.endpointcomputing.com a scientific approach to custom computing.
They like cell phones (you may have noticed). You can charge current cell phones from usb. Swipe a USB cable from a pawn shop and get some 7805 regulators from digikey/newark/jameco. Add a 6 volt lantern battery, and you can charge your cell phone anywhere. Or grab some cigarette lighter plugs from the pawn shop and you have a car charger. Total cost should just barely come in under your $5 level, *and actually be useful and relevant to them*.
It's related to something they're interested in already. Some will like, others will electrocute themselves.
And then we will find you under the bridge, transformed to a oscillating hunchback.
I'd start with a crystal radio, although there are designs far more compact than the one on Wikipedia. Next, perhaps a simple transistor amplifier (for which you can use the crystal radio as an audio source), then it might be time to move on to the thousand and one projects you can build around a 555 timer chip and some LEDs.
All of these are low power, low cost, and produce a visible or audible result for immediate gratification.
Mal-2
How is the Riemann zeta function like Trump rallies? Both have an endless number of trivial zeros.
I just taught a unit on electronics. We used breadboards and the 555 ic to build optical theremins. I have the entire curriculum done. contact me through /.
http://blog.makezine.com/archive/2009/01/weekend_project_simple_laser_commun.html?CMP=OTC-0D6B48984890
Every kid has headphones....and those laser pointers can be had for like 2$ on ebay
Once you get past the sunk cost of a programmer, a PIC is a great way to go. You can get free samples on any of them. Beyond that:
Solderless Breadboard
LED
Resistor
Capacitor
Battery Source
Should be had for around $5
Hey,
I agree that this type of opportunity should be seen more even in college. I would take a look at the SparkFun website. You can also contact them, I know they hold events in various places to up electronics interest. They may have a program to purchase simple projects in bulk at a discount rate for schools. I have purchased many items from them for various electronic projects I have worked on.
www.sparkfun.com
the next class can use to build more things.
VOlt meters, O-Scopes cards for a computer.
You could also go to the local place that people donate there crap computers, get a coupkld of those and build a cprogramable PCI card. Possible get one donated for a local electronics corporation.
For example, if you are in Oregon, contact Intel and see if you can get donations from them. They, and Mentor Graphics, were very helpful to our school when they did the robotics tournaments.
The Kruger Dunning explains most post on
If they are still in business or you can find somebody who still has their old texts.
Heath had a dozen continuing education courses in core electronics with over a hundred interesting projects from 555 timers to Digital Techniques and Logic.
All you need is a breadboard with low voltage power, the discrete components (most of witch have a price in the pennies. A multimeter, and in some cases access to an oscilloscope.
The courses were not expensive, may be still available, and I bet somebody in the community still has them tucked away in their attic.
Tom
I would recommend something like a solar engine car or something similar. These are both cheap and easy for kids to make. Plus, you can have the kids race them. ;)
Something like this, perhaps they could work out a deal with you to get it down to a more reasonable price: http://www.solarbotics.com/products/make06solarroller/
$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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I would work with the kids on batteryless flashlights. Build off the concepts of a dynamo and capacitance system and you end up with not only a good project for low cost, but a useful household item with a "green" solution.
There's always the good old motor made of a coil of magnet wire, a battery, and a magnet.
For a little more than $5, you can buy a bag of cheap laser diodes off ebay, a couple of 1k-to-8ohm audio transformers, and a photodiode or photovoltaic cell (keep it as small as possible) and build something that plugs into an mp3 player phono jack and transmits sound via laser. Here's one implementation, and many others exist. I've built these and they're pretty easy.
For that matter, since laser diodes are so cheap, you can also make a pretty good seismometer with a laser diode, some cheap crappy fiber optic cable in a tangle, and a photodiode. The fiber optic could even be glass you've drawn, if I recall correctly.
I've made several coilguns, but those are a little more exciting. Wind up a good coil of magnet wire, around a core of lots of welding rod cut at different lengths. Put a hoop of metal, preferably aluminum, around it on top of the coil, and briefly connect the coil to 110v, and watch your metal hoop fly. With some care in coil inductance and adding some caps for tuning, you can put a ring through a piece of plywood.
Nostalgia's not what it used to be.
diode, resistor and capacitor. It will drive a _very_ high impedance earphone.
antenna is a _long_ piece of wire, or get the ferrite version from a junker radio.
it's modern electronics and is wireless ?
add a little pizazz with an op-amp as an audio amplifier.
Absolute statements are never true
An audio splitter for, a mp3 player, or just a headphone jack split. Maybe you could put in some circutry to amplify? Or get some kind of custom ipod cable (ive heard that they are popular mp3 players). Maybe some buttons and stuff to switch tracks?
I am sure if someone made electronics relevant to me in that way when i was growing up, i would have busted out the soldering iron alot sooner than I did.
As a potential lottery winner, I totally support tax cuts for the wealthy
I know how fun it can be to get your hands dirty, and its amazing how empowering it feels once you realize that you can build your own circuts, but if you're on a tight budget, why not turn to simulated circuts. There are plenty of flash apps and games like Gate out there.
Assuming you have the proto boards already, $5 is not out of line for a number of fun little projects.
If they are programming already though, you're closing a whole world of fun by not letting them interface to them e.g. a thermistor temperature sensor is pretty boring, a temp sensor that records the last 24 hours to ram and lets you dump it to your computer is a "tool of discovery."
I think an ATtiny2313, with it's 2k of ram, 128 bytes of SRAM, 128 bytes of flash and hardware UART makes a great interface to whatever electronics they are working on, and is not so much a "computer" that this becomes a software project. So with $2 per project tied up with that chip....
Start with the "transistor based" port-powered RS-232 interface instead of the max232. They'll learn about using transistors as switches, and it's easy to t-shoot when it's done wrong.
Now any analog circuit you want to show them is the cost of the components and hooking it to the 2313's analog comparator, one leg of that comparitor can be tied to a voltage divider, letting them set the cut-offs in "analog world."
A couple seven segment LED displays or an 8 segment bargraph can make for instant feedback.
It makes it easy to:
* Check the optimal angle of a solar cell over 24 hour period.
* Wire up 8 output leads power-of-two resistors to make an analog output that they can use to tweak analog circuits like audio warblers.
* Use the PWM output, a capacitor and inductor to drive a motor and illustrate (I trust you own a scope) power smoothing and switched power supply operation.
* Use an old floppy head-positioner leadscrew to adjust a solar panel's angle based on it's output
* For advanced kids:
1. Creates 10khz RC oscillator, use transistors (or cheat and use an LM386) to amplify it to a small speaker, gate it with an output from your microcontroller....
2. Put an simple pair of high-pass and low-pass filters on your mic. input (centering on 10khz), rectify it, and have it trigger a debounced input to the micro, and with a little help from the onboard timer, you have cheap sonar, which is very very fun.
I think the analog world is best discovered with the help of digital recording and determinism, but it's your $5...
What about getting junked electronics (thinking Goodwill here, or possibly even donated) and desoldering components to build other projects with?
I Am My Own Worst Enemy
7 switches to turn on different segments.
Then you can introduce the decoder and binary (BCD) numbers translated to decimal display.
A simple transistor oscillator is a good place to start. A simple class A voltage amplifier can be built with one PNP or NPN transistor, a few resistors and capacitors. It's a good way to demonstrate how small changes in the base current regulate the current flow across the junction. Old fashion TTL chips are still available. Five dollars worth of TTL chips, some LEDs for output indicators, some breadboard sockets can help students understand how logic gates such as AND, OR, NAND, NOR work. Ambitious students might cobble together a four bit ALU. It would give them an appreciation of the computer in their cellphone. Frequency splitter circuits such as those used in speaker crossover networks might be of interest. These can show how capacitors block low frequency. All of these can run on low voltage
You're going to have a tough time building anything practical for a $5 budget. I'm going to assume you mean $5 per student with a class of around 30 - you can't usually buy resistors or the like in quantities of "1", and just a (decent) breadboard can't be had for less than $5 unless you're buying in bulk. It would be best to have each student (or small teams) build it themselves. If you're at the front building and describing, they'll just tune out.
I would build some simple resistor ladders, which is probably all the course material covers. Have them put several LEDs in different parts of the circuit, and then play with the number and size of resistors in each leg of the ladder to show them, visually, that the voltage and current are changing.
You can show them capacitors by putting the battery in parallel with a big-ish cap, then have them remove the battery and watch the LED slowly dim and die.
If you want to bring transistors into the mix for sub-$5, it'd probably have to be a single transistor switching the power supply, with a pull-up wire to turn it on and off. You could maybe move it to different legs of the ladder. But I'd actually advise against transistors unless you want to go all-out and have them build an AND / OR gate. If you just show them transistor == switch, without showing them all the useful stuff it can do, they won't be very impressed.
If you have a digital multimeter, it would also be very instructive to build one demo circuit at the front of the class and measure the voltage at different points, to show them the values and prove something really is happening in there.
Anything more complicated than this, like RC oscillators or inductance, is going to be both expensive and way way over the heads of a 9th-grade class. At least, if you actually want to teach the physics of what's happening. If you just want to say "connect thingy A to jigamabob B and watch the light blink!" then sure, go for it!
LED lights are a cheap fun way to teach some basics. All you need is a battery (or even better, several different batteries with different voltages), an LED (or several LED's with different voltages), and a bunch of resistors.
You can get packs of green, red, and yellow LED's for less than 50 cents an LED. resistors are a buck for packs of 10. And batteries are batteries. Figuring out the resistor needed to light up an LED based on the voltage from a single battery or series of batteries can be neat.
If you want to take it a step further, bring in some 50 cent USB a-b cables. Slash them and toss out the B side, find the 5V and ground line, and have them figure out the resistor needed to light an LED for USB voltage (like a woot light!). USB power = 5V 100ma usually (it goes up to 500ma, but the driver usually has to negotiate it up; it should be 100ma; buy a cheap powered hub if you want to keep it safe from the computer). There are lots of links on how to figure out the voltage of an LED, this one is ok.
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 need to keep it simple, but fun.
I used a photo sensor, small transistor, power transistor, and 1Amp 12Volt light bulb.
Wired to when sensor sees light, bulb goes out.
If it sees itself, it makes an oscillator.
If multiple folks in the class make them, they interact.
You maybe able arrange them into gates and flipflops if you have enough.
(Also an opportunity to try fibers.)
(I also tried a smaller bulb for the bias resistor so you can see what is going on in the circuit, but that was too much for the kids.)
The circuits were built on a 2 by 6 inch pcb with the copper cut in half length wise.
One side was ground, the other side +12.
Parts soldered in 3d above the copper.
Power from a gel cell with a series ballast to prevent fires.
Ballast was 4 tail light bulbs in parallel.
This lights up nicely when you short something out.
With a couple junk telephones you can build a radio. There are even some guides here and there that show you how to make a variable potentiometer, switches, batteries, etc., from tin and aluminum cans and a few sheets of acetate (such as in a clear plastic report cover).
Old remote controls, busted transistor radios, old calculators are a goldmine. With them you can make some very simple circuits. For example, with a few transistors and diodes you can make a binary adding machine. It can demonstrate how a computer does a shift or an add, AND, ORs, etc..
There's a page online somewhere with instructions on how to build a car that drives around. When it approaches a wall it will turn around. It uses pieces scrounged from motherboards and CDROM drives.
Check out scitoys.com for some ideas. The section with a radio is pretty darn cool, and he does have a few simple projects like a 1-Watt amplifier and a laser audio transmitter. No soldering needed, which is a plus for a school setting with 9th graders.
steveha
lf(1): it's like ls(1) but sorts filenames by extension, tersely
Use an arduino clone.
http://www.arduino.cc/
Check out the Rock Bottom Freeduino Kit @ http://wulfden/ ( dot ) org/TheShoppe/freeduino/rbfk.shtml
Link has been edited to prevent the site from getting slashdotted.
I built one of these when I was a kid. Talk about low-cost. And you can skip the tuner part. The combination of pencil lead and a razor-blade acts like the diode. So, if you have a strong enough signal, you can get by without the fancy tuner.
http://bizarrelabs.com/foxhole.htm
a small guitar amp or an overdrive stompbox are pretty easy to build from discrete components and you can hear if they work or not.
"It's such a fine line between stupid and clever" -- David St. Hubbins, Spinal Tap
You can make all sorts of feedback curcuits with a few transistors(act as termostats) some swicthes, a few resitors a few LM324 ot similar amplifies and maybe some more advanced sensors, this kind of stuff is a few doller a set at a bulk retailer, you can make oscilating lights controled by stuff happening in the room with some diodes again dirt cheap and som RC(resistor capacitor) circuits.
"AND" gates are also avaliable cheaply so you could do all sorts of digital fun aswell.
Make little moving junkbots, examples: Mark Tilden's.
Most equipment can be scrounged from old parts that a University would gladly donate to get rid of (for instance, Capacitors, resistors, etc.etc.) There are also parts in old electronics just thrown out at the dump, and the kids get to learn how to read information on the electrical components.
Oblig. Wikipedia Article
in girum imus nocte et consumimur igni
A friend of mine made a stobe light in his high school science class. His plugged into the wall, but a safer and lower-cost option would be to use a battery. It had a pot on it, so he could vary the frequency of the strobe. He also made a cool case with a reflector. You could do this with a few RLC components, a couple of transistors, and an LED bulb. A quick google search will provide you with a variety of schematics that will meet your cost and complexity constraints.
I played a lot with these sorts of projects when I was young. I really enjoyed the little books by Forrest M. Mims III at Radio Shack. This book is probably stocked with good ideas.
Using a wire wrapping tool could be a good way to construct circuits without using solder. You can also use breadboards. The breadboards are easier to work with, and can be reused by several classes. However, with the wire wrapping approach, you may be able to make the project cheap enough for the students to keep what they build.
I once made a "darkness detector" or night light which would light up an LED when a room was dark. It was kind of cool because it all fit inside a little plastic film canister. All it needs is an LED, a photoresistor, a watch battery, an on/off switch, and a transistor. (And perhaps a simple resistor.) It can all be wired up using the wire wrapping tool. It's more of a toy than a useful item, but it's so cheap that it could be something they can take home to keep.
A common Tesla Coil can be made for this budget simply, and would definately get any childs attention. basic schematics can be found all over the net.
Karma Whoring for Fun and Profit.
Knock yourself out
http://search.dse.com.au/nav/cat2/electronicsandkitsets_kitsets/cat1/electronicsandkitsets/0
As an aside, 25 years ago I won a competition in high school with dick smith with a prize of $50 worth of electronic components.
I was thinking beauty, the things I'll be able to make!
What did I get?
just what every kid wants... a box of 5000 22pF NPO capacitors...
46137
A computer power supply will give you 5 volts and 12 volts. They are completely enclosed and safe.
A CRT monitor will give you a bunch of parts. In particular, the horizontal oscillator transistor is virtually bullet proof. The de-gaussing coil is a good source of magnet wire. You have to find a way to get rid of the CRT tubes safely. Don't leave any of the circuitry together, especially the power supply. A monitor power supply isn't protected and has totally dangerous voltages.
Old floppy drives are good for stepper motors. The controller board takes only a couple of signals, step and direction. You can drive the controller board signals with the parallel port.
I used to epoxy stepper motors and microswitches to lego blocks for student robotic projects. Another favorite project was a class A audio amp using the aforementioned horz. output transistor.
You can teach electronics for just about nothing. For an oscilloscope, you can use a computer sound card.
Calculations involving current, voltage, resistance, and parallel circuits.
LED lighting strikes me as useful, fun, and certainly a range of skills to build.
Cheap too.
Maurice W. Hilarius Voice: (778) 347-9907
I think the scrounging idea is a good one...you'll be able to pull resistors off of anything, and everybody will learn the codes quickly. Have them bring in something simple in their house that doesn't work - have them troubleshoot and repair it (permission, obviously...).
Have them bring in an annoying electronic toy and have them wire a volume control into it. For that matter, have them bend circuits on all the electronic crap that surrounds us today.
Finally, talk to your later Radio Shack / Fry's / whatever, and see if you can get them to sponsor the class with some free gear and projects.
If you end up with some more coin, try a TV-B-Gone:
http://www.adafruit.com/index.php?main_page=index&cPath=20&sessid=5bf624d376f9c6c44a119200f35c990d
AdaFruit has a lot of good stuff. One thing I saw at a Make Faire was a project where you quickly build an oscillator using a paper circuit board and a pencil line drawn on a paper to have a quickie musical instrument.
If your bitterest enemies are people who hack the heads off civilians, then I would say you're doing something right.
Bring out the carpet and sneakers, then *pop*.
Combine the exercise with theory.
1) Is fun
For the aggressor
2) Teaches about circuits that are relevant to their life.
Everyday relevance
3) Doesn't rely too heavily on a black box microcontroller.
Done
4)It must be as cheap as possible
It does not get any cheaper.
I don't think I could suggest anything as low as $5, but have you looked into Arduino boards? They are fun, cheap and easy and would be perfect for high schoolers. I am using them in my own high school level education program teaching rocketry and using arduino to design the science payloads they carry. If you could get a little startup money you could buy the boards and easily spend $5/year per student on the jumpers and devices to do the experiments and learn the physics.
cheap because it uses passive components and demonstrates the attenuation concept. Filters can be applied to all kinds of signals. Selective tuning, notch filters, lot's of fun can be had with a fewelements!
Have everyone build a nand gate. Combine these nand gates into or and xor gates. Build a half adder. Chain the adders together to form a full bit. Wire up a 555 timer to push in a bit and show that the adder is adding each new bit to the value. If you want to keep accumulating these small circuits over time you could build a full working computer that is 4 bit and has a few bytes of data storage.
Tanner Electronics in Dallas http://www.tannerelectronics.com/ has a bunch of low cost kits for beginners. Give them a call and see if they have anything you might be looking for.
ask FatMan and Circuit Girl.. CircuitGirl is the one that di dthe old style game sin one little game controller to run on TV..as one chip..website: http://www.fatmanandcircuitgirl.com/ She also does chip fabrication without caustic chemicals using household chemicals and easy bake ovens..
Fred Grott(aka shareme) http://mobilebytes.wordpress.com
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.
Made one of these in a college power systems class. All you'd need is a magnet, some wire, and a D battery. Teach your kids about electricity and magnetism at the same time.
Want to add more electronics? Spin the motor and measure the voltage across the terminals, use the micro controller to convert the voltage to rpm display.
Since (along with 99% of the world's population) I can't covert "9th graders" to meaningful SI units, I'll keep my suggestions to myself and you can whistle Dixie for all I fucking care.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
To find Richard B. Cheney et al.
Thanks for your efforts in crime fighting.
Yours ELECTRONically,
Kilgore Trout
This MeFi entry has a bunch of suggestions:
Where are the beginner-level electronic kits to be found?
Not the safest option, but could always go old school and have them build their own capacitors, inductors, batteries and make basic circuits... Just need pvc tube, copper sheet, copper wire, lead sheet, etc.
#603
The only person who is less smart now is you.
Don't think of it as a flame---it's more like an argument that does 3d6 fire damage
http://www.parallax.com/tabid/182/List/0/CategoryID/67/Level/a/SortField/0/Default.aspx
parallax has all kinds of kits on electronics and microcontrollers.... and they do volume discounts for educators....
blah blah black box microcontroller.....
what are they learning programming with?
check out the "what is a microcontroller?" kit...
it's based on a BASIC Stamp, and yes, bloack box, etc etc.... but... the kit has a proto board and many "basic components"
it;s better than going to adio shack and buying a bunch of parts they won't be able to use for anything else...
You're a *physics* teacher ... show them "lifter", "swimming LEDs", "neon life" or that experiment that MIT professor does where he generated high voltages with nothing but buckets of water a buckets ..!
Radio shack used to sell learning books/pamphlets in their electronics section.
The large one was by forrest Mims, but might not be sold anymore.
along with that they sold small 8X5 softback books, with around 40 pages that taught basic electronics theory.
they were called "Engineer's Mini-Notebook: "
the topics included
The complete set includes:
* 555 Timer Circuits
* Basic Semiconductor Circuits
* Communications Projects
* Digital Logic Circuits
* Environmental Projects
* Formulas, Tables, and Basic Circuits
* Magnet and Sensor Projects
* Op-amp IC Circuits
* Optoelectronic Circuits
* Schematic Symbols, Device Packages, Design and Testing
* Science Projects
* Sensor Projects
* Solar Cell Projects
Search on amazon.com for "Forrest Mims" (note the spelling of the first name)
Most of the mini-notebooks are less than $5 and are available as used. He has updated his books and they sell those on amazon as well.
You should be able to find a simple project for your students to build for less than $5 or $10 bucks.
good luck
Get the chemistry teacher to help you and make a trench(foxhole) radio. Then build a crystal radio. Then an audio amplifier circuit. Or build the crysal radio then the audio amplifier then the foxhole radio. But actually building a radio with parts they've made and not bought, making the diode, will teach them a lot.
At school in 10th grade we had to build a diorama based around a 555 timer. I was playing half-life at the time so I wanted to incorporate the alarm sound from the 'resonance cascade' at the beginning. I asked my teacher if I could do that and he went mental. Apparently he had just given a 15 minute lecture about why we wouldn't be able to do that and I wasn't listening... :-\
A vibrator is a simple circuit, useful (He said high school), and teaches the basics of anatomy in a practical manner.
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."
Unfortunately, I don't remember the circuit exactly, but one of the most interesting demonstrations I saw was transmitting sound from an iPod using an LED shining on a solar panel, amplified with what I believe was a single transistor and a 9-volt battery, and finally played through a speaker.
Cheap solar panels are fairly easy to come by, courtesy of Edmund Scientific and the like. The other parts can all be scavenged from various cheap sources and broken things. Incidentally, I'm also in favor of high-schoolers learning how to properly solder, as I didn't do until college.
You do not have a moral or legal right to do absolutely anything you want.
Your budget limits you to a couple of ICs a stripboard and a few other components. Use something like a 555 with an LM386 audio amp and various C / R combinations for the tones. However, before you start them on electronics, you'll have to buy some soldering irons and teach them to solder - provided your health and safety regulations allow such hazardous activities.
politicians are like babies' nappies: they should both be changed regularly and for the same reasons
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.)
MIT's Walter Lewin Makes a Battery out of Cans and Water (Schauberger's Tech)
Prof Lewin is a madman and I love him. Wish I could go to MIT just to hang out with the guy all day.
There are lots and lots of interesting things you can do with a humble 555.
-fb Everything not expressly forbidden is now mandatory.
You could build a rudementary electric telegraph system within your budget. Press down the button, it causes a "click" by magnetizing a clap-bar. Very simple circuit.
Karma Whoring for Fun and Profit.
Kids in America not only have no interest in things like science and electronics, but there's not going to be any jobs in it when they finish college. So teaching this stuff to them is a waste of time. Stick to teaching them things like marketing and law, since that's what they'll all want to go into in college anyway.
Get creative with parts. Use cardboard or sheet plastic for the circuit board material (careful not to melt the plastic with soldering irons). Use a cereal box, or some other small box, or PVC for the project box. Get the kids to bring creative parts from home.
Build a metal detector.
The Electronic Goldmine and others offer assorted parts in an unsorted box for cheap. You could buy bulk parts like this and have the kids sort them (make them learn how to measure components in the process). As a warning, sometimes you get a lot of what you don't need and very little of what you do. Resistors and capacitors can be combined to get what you need most of the time, but not always the case with the ICs. Get those from Mouser or Digikey. Read Make Blog for ideas, they're good. Recently they linked to a guy using a sponge and ferric chloride to etch circuit boards cheap, easy and fast.
Might be a bit too pricey. Have your Visa ready.
Why not have them build their own crystal AM radio, totally old-school style? Wind their own coils, use a piece of wood for the base and another for the coil form (piece of hardwood dowel?). You can still find 1N34 or 1N60 germanium diodes to use as the detector, and just about any ceramic disc 0.01uF capacitor for the filter. Most expensive parts would be the 365pF variable capacitor and a crystal headphone; magnet wire of an appropriate gauge would be relatively cheap per unit, coming off a single spool. Antenna can be just another length of the same magnet wire, or if you have some bare solid wire around, so much the better. As the object of lesson(s) in basic electronics, it's still a goldmine, you can teach them about tuned circuits, modulation methods, etc.
Are YOU using the TOOL, or is the TOOL using YOU? Think about it!
I am taking a collage level physics lab right now, and we just did a lab on RC circuits; I thought it was cool to learn how the RC circuits could be used as high-pass or low-pass filter for a speaker(It was cool to remember seeing an RC circuit in the sub woofer I had installed in my car years ago(but did not know what it was at the time). I was like wow. I know how that works now :) ). Any ways I would suggest looking at what is being done in some university physics labs and 'borrow' there good ideas. yea a lot the labs are kinda boring but there are some good ones.
Yes, yes, you have $5 to spend. How many students? What about a grant?
Look, if you are teaching physics then you can integrate a full robotics platform into the entire course. Your labs will come alive and be compelling. Most of the answers to this point are geek answers and you don't need to teach geeks physics, they will learn it even if you took the books away. No theremin or oscillator is going to be any more interesting to the average 9th grader than a flashlight bulb.
The fact is that you can't teach them modern electronics in a 9th grade classroom. Modern electronics is software assisted IC design, it involved expensive diagnostic tools or chip programming tools. Electronics is taught the way it is because the fundamentals are easy to understand and useful as you move forward.
However, if you are still convinced that you should go down this path then at least turn it around. In biology we learn how a frog works in a book and then we take it apart to see it for ourselves. Have your students bring in an inexpensive electronic device and take it apart. They may be worthless for there original function after that, but it might be interesting to see how the parts could be combined.
Finally, "The Dangerous Book for Boys" has a couple of easy projects in it.
You could make an LED night light with a timer shut-off. This would be about as simple as you can get with active components. Probably best to use a potentiometer to adjust the time delay - in real use, you'd want >30 minutes, but the kids will want to try it out with 30 seconds.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
Ionocraft: Flight Without Movement
MythBusters covered this and decided it was not "anti-gravity" ... but what I can't help but wondering about was the claim that you could do this experiment with DC, reverse the polarity and it supposedly doesn't matter!
Have them build a multimeter. They'll wind up with a useful gadget, one they can use on future projects.
When our name is on the back of your car, we're behind you all the way!
There are two projects I think are well suited for this purpose. A CC stripe reader or a SIM card reader. Both are very simple circuits, both require exactly one specialized piece of hardware (the SIM reader or the tape reader--and old cassette player head works fine). Both can provide data to the COM port to any computer, and need only very simple software to manipulate.
What about a simple FM radio? I found this project a lot of fun http://sci-toys.com/scitoys/scitoys/radio/three_penny/three_penny.html and after building it with my nephew is started a whole series of experiments and visits to Radio Shackk for them.
a whole plethora of electronic and physics principles:
Weather; torque; electromagnetic force; volts; amps; ac; Phase the list is endless.
Its VERY relevant to all kids (green energy etc)... you can even roll it into "how to conserve energy" process etc..
and easy to teach how it works to make some very easy-to-build wood items out of scrap.
Strip a few hard disks and you get the magnets (be careful - they can be more dangerous... might want to use less powerful ones for kids);
strip an old TV for the copper wire stock. Stators made out of wood; props from wood...
or Look up VAWT (vertical)... and you can get some ideas of some basic designs (like a couple of coffee tins cut in half and put in 180o phase.
There are even whole teaching manuals on the 'net that will help you design the teaching program....
its all there for you..
I did many in my high school electronics class
but the parallel port interface was probably about the best one
I have the schematics and documentation on it may even have one around still
we used basic IE Qbasic to program ours at first then self tought moved on to C
after finding pascal to crude
we built them at them begining of my grade 10 year I think and 4 of us used them in
many projects after for the remander of high school throught our robotics projects and all
grant this was 12 years ago before heavy use of microcontrollers
the other option would be have them build a knock off adurino and then make it do something
it will give those that enjoy it something that they can take and use at home to further themselves
I'm sure I had 3 interfaces built by the time I was don high school using 2 on one pc some times
2 pc's and 3 to control large projects
Have them make healing magnetic bracelets and then have them fight students from an intelligent design class. Which ever group wins is right! So you'll teach them to test their theories and all while teaching them survival of the fittest. Suck it intelligent design! :P
Quack, quack.
So easy and cheap to build, a school girl can build one! Hence the name of the motor...
http://peswiki.com/energy/Directory:Bedini_SG
You can use junk or buy most of the parts at radioshack. Not only is it easy to build, but, it will entice the student to learn more. When a person really gets to know this simple circuit they soon starts to realize that physics, chemistry, math, etc. are also subjects of study to fully understand what exactly the circuit is doing. Best yet, it's open source!
Firstly, don't knock light bulbs and batteries as they teach the basic concepts of series, parallel, and series-parallel circuits and digital logic (AND, OR, NOR, etc), secondly for $5 dollars you won't be doing much with modern electronics as they require FPGAs, ASICs, DSPs, etc. A silicon diode has a 1V/degree celsius response and as such makes a handy temperature gauge. I have used this as a college lab where students take a temperature reading, apply heat and then take a reading with the diode thermometer and calculate the change in temperature. This helps the students understand the role of components as well as the effect of temperature on electronic components.
555 is a good idea, but opamps may be better. You have the option of building oscillators, amplfiers, active filters, and even analog computing circuits. If your 9th graders are proficient with algebra, they can even predict the output of most of these circuits. This can provide a window into the practical application of mathematics and might even intice the more motivated students to learn how and why the circuit models and math allow predictions to be made. A decent performance opamp (TL074, quad FET input) can be had for less than a dollar at Digikey. Resistors and capacitors are inexpensive if bought in reasonable bulk (1% resistors are $8.12 for 200, at Digikey, less at surplus places like All Electronics, though selection will be spotty). The big cost will be in the prototyping board for wiring all of this together, although they are very reusable (about $8.00 at Digikey, $4.00 at All Electronics). $5.00 per student is doable for the consumables, but figure about $15.00 to get started.
Public school in the US, and you want them to build something that'll be relevant in their lives? Try a taser (an electrical chair is probably a bit more expensive).
I remember building an processor back in early high school.
The whole class worked together to build small units that, when combined, formed a simple binary calculator. It was a lot of fun, and used basic components plus some wood to put the components on. In the end, it was a huge device, but it worked.
It really helped me understand the amazingly fine work on modern processors, and having actually built a computer was quite cool.
Have them make a theremin [wikipedia.org] (see the "Similar instruments" section as well). It makes spooky music. Great for a late-October/Halloween project.
Better yet have them build an E-Meter. Since it is just a Wheatstone bridge they can learn something about physics. It doesn't produce spooky music but it would be great for scaring their parents at Hallowe'en.... "Mum, Dad look what I got for signing up with the scientologists!".
Lot's of good suggestions here. Here's what I would do. Get yourself one of those 100-in-one project kits, or 400-in-1, work through it, and from there, pick a handful that would work with your students. You can then buy the parts you need in bulk - a 1000 resistors here, a 100 caps, 50 transistors, 100 diodes, etc - all cheap. Put together a parts box with all that stuff, including wire, solder, bulbs, led's, battery clips, alligator leads, etc. Then get a few basic durable goods - soldering irons, a multimeter, etc. You will also need some breadboards and solder boards. Each year, you can add a few projects and components, and soon enough you will have a real electronics workshop.
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Whatever specific projects you choose, they should represent the basics: basic circuits, basic components, r-c, basic logic, gates, timing, oscillators and mv's, mux-demux, comparators, etc. Five or ten basic building block IC's should be able to cover hundreds of projects in these basic categories. There is nothing like a good ol' 555 for timing projects, 7400's for starter digital logic, and a 741 for introduction to analog concepts. Almost any project you will find in a 100-in-1 kit will be easy enough to build for under $5 once you have the basic lab or shop equipment.
Jeri Ellsworth has been building very simple integrated circuits by hand in her kitchen. See http://vimeo.com/channels/26257 for a tour of her home chip lab.
ok, some good points and rules for fun high school electronics
1) Relays are cool, they make a sound, you can see how they work and you can get a mild shock when they deenergises if you donâ(TM)t have a diode in circuit. You can also build almost anything with them. (binary adder, combination lock, etc..)
2) LED are cool (kind of goes without saying really)
3) reed switches + magnets are interesting (you can have objects rotating and triggering the reed once per rev)
4) avoid buzzers/speakers (unless you want to be deafened by 25 going off at once)
5) everyone likes seeing a capacitor explode
6) as mentioned before, unsoldering and reusing old components off old boards is a good idea. Teaches soldering skills, saves money and if the student damages the board it doesnâ(TM)t really matter. You can even ask the students to bring in any old electronic devices they donâ(TM)t want, and then take them apart for parts.
7) ask for ideas for what to build from the students, they will know what they find interesting better than you.
Some other project ideas are:
- Red, Green and Blue leds wired up to pots that allow the student to mix the colours to create any colour. (very simple but still interesting)
- IR diode + sensor showing how shop door sensors detect when you break the beam
- PWM demonstration using a 555. showing how switching a light on/off fast can control its brightness with no power loss
I did this one with my daughter for a science fair project. For me, the parts DID cost more than $5, but there were a lot of things I bought singly, but would have the cost lowered spread out over multiple applications; bag of rubber bands, one long piece of PVC, wood, nails, etc...Also many pieces can be brought from home to lower the cost.
While the results were never that spectacular, given more time, and less baling wire construction, it might be fun and educational. You can throw in lessons about resistors and capacitors then use it to power something bigger.While it won't help much for logic gates, you gotta start somewhere.
How to build a generator
Hello-
I have some experience with this problem. You're right that microcontrollers are too advanced, everyone gets bogged down in the development tools. I also find that most types of IC and transistor circuits where you can't SEE what is happening don't really work out for most kids.
A few kids will get really into it. The next group will 'sort of' get things to work by following the directions, but not understanding what is actually happening. The rest will just sit there while everybody else plays around. They won't even try.
I have found that the basics like lightbulbs, batteries, and switches really get kids excited. They can see what's going on and they understand it and start building on it. Flipping a switch or pressing a button to make something happen is very empowering.
Next, if you can get a hold of some nice relays, especially ones with clear housings, they are really useful for this. It's a switch that turns on another switch. They understand it. (especially with a DPDT knife switch to explain things) Try a reed switch and a magnet, controlling a bulb through a relay. (small switch controls big switch... They learn about current) Let them try the NC contacts. Show them a relay LATCH. Connect the coil through the NC contacts for a relay buzzer. Add a speaker across the coil for a louder buzz. Can you combine these and make a burgler alarm? Show them that a mechanical bell or buzzer is the same as the NC relay buzzer. Next, put a capacitor on the relay coil for a delay. They will UNDERSTAND all this and get into it. And they like the clicking.
This lets them learn by using things they understand like switches and bulbs which are all doing things they can actually see. There are no black boxes at all. Also, a lot of kids want to ignore you and just play. With these parts, they can still make things happen and learn just by messing around. Can they get the relay to click? Make the bulb light up?
I've taught a lot of workshops to beginners and most breadboard type stuff really just confuses them. It seems they have made up their minds in advance that this is something they can't do, it's too hard. With the knife switches, batteries, bulbs and relays, they got really excited. When we added the capacitor they really understood what those did. It seems that this is a necessary first step before you move on to 'black box' parts.
Once you've gotten them there, the next thing is an optoisolator, which is really just a relay. Then they're comfortable with a DIP package, and you can proceed to the 555 and such with the ones you haven't lost. In the meantime, skip all semiconductors completely, except the rectifier diode, which they understand, and maybe the LED (with resistor already soldered on).
As we get better at electronics it becomes more and more difficult to understand what it was like to not know anything about electronics. You try to explain a 555 or op amp and there are a thousand details that you're taking for granted without knowing it. The other person really can't get it without the details, which makes it very hard to teach the subject without losing people. This is why you should go for the basics as much as you can. Let them play in that safe zone and master it and build a foundation before moving on.
Skip Ohm's law and the RC circuits and the math stuff for now. Let 'em turn things on and off. They'll get it.
List: Knife switch, lever switch with roller, button. Reed switch and magnet. Buzzer, bulb, rectifier diode. Clear relays, at least SPDT, DPDT better. Capacitor that can hold the relay on for 1 sec. LED with resistor installed. Speaker with resistor inline (so it can go across the battery without blowing up) . Batteries to match all these (9V or 12V is easiest)
Show them some examples and let 'em go nuts!
Teach them about basic NAND/NOT/NOT logic gates
Show them how to build a two state flip-flop out of two NAND (or NOR) gates, then how to combine flip-flops into a larger state machine
A nice demo is then to build a toggle-switch driven state machine using the states to power a few different color LEDs (e.g. red/yellow/green traffic light sequence)
This is a very low cost project other than a breadboard/power supply (or battery) you just need some 7400 NAND gates, LEDs and toggle switches. It's a good basic and fun introduction to digital logic.
Circuits based on the 555 or 556 timer are good to start with, and 555's can be found in numerous old electronic devices, as it was one of the most popular chips ever made. RatShack used to sell an engineers guide to 555 circuits, and was very useful in teaching the fundamentals of what could be done with one (or 2 in the case of the 556), along with some more complicated designs (including a simple oscilloscope that used some sort of multiplexer IC to display waveforms on a panel of LED's - very cool).
I'm assuming that you have access to power supplies and prototype boards and patch wire. Other than that, the components for the projects in those books are cheap. Oddly enough, I teach a similar type of course, so I know how tough it is. My best advice is to approach something like Chevron, Exxon Mobil etc to get seed money for the prototype boards and a basic set of components that should last a couple of years. After that, you can probably arrange to smaller scale fundraisers to replace dead/lost chips etc. Anyways, don't let the problems outweigh the cool benefits of your project.
My girlfriend texted me today asking me to build a circuit that will open her blinds instead of setting off an alarm so she wakes up to sunlight instead of *BEEP BEEP BEEP*. Probably not a difficult task for 9th graders and could possibly be used afterwards instead of thrown out at the end of the class.
Teaches use of resistors and LEDs (use one to regulate current direction). Kids'll eat it up.
Don't do it yourself.
Get in touch with the local Ham Radio group or some other homebrew club (no, not that kind of brew). Perhaps a local Robotics society. You should find quite a number of people who are enthusiastic and knowledgeable about electronics. Work out some cheap and easy one-class, or one-week kinds of projects. If you're a good salesman, you might be able to get them to dig through their junkboxes and come up with the appropriate parts for free. Heaven knows I have a box of through-hole R's and C's that I'll never use, along with dozens of 4000 series CMOS and various powered breadboards. If a teacher with your enthusiasm came up, I'd be more than happy to share (or show up once a week as the visiting mad scientist).
With the volunteers, you can build all of the things mentioned above - radios, audio amplifiers, games, music makers, light organs, telegraphs/telephones, light-beam based phones, quiz show buttons (four buttons per team, with a light for the first button and a lockout on the other buttons; run a quiz show after building the device), replacement radio control for a broken RC christmas toy, digital circuits.
Teach them chemistry; both Ferric Chloride and Ammonium Persulfate etching are cheap and can be used to make PCBs or copper decorations (put the same resist pattern on both sides of a thin copper sheet). The PCBs can be used for the projects if necessary, the decorations to keep them interested.
Look at geeks.com or dealextreme.com for ideas of cheap little toys; and get the kids to reproduce them. Look to sciplus.com or goldmine-elec.com for unique bits and pieces and cheap parts. LEDs are always interesting; use'em.
As Lockhart's Lament (http://plato.asu.edu/LockhartsLament.pdf) argues, giving them a problem they care about and helping them to solve it is going to go a long ways towards keeping their interest compared to (in the voice of Ben Stein) "This, children, is the symbol for a resistor. It has the following characteristics...".
Good luck,
And the worms ate into his brain.
Make an electric motor out of a board, coil of 7 turns of wire, two paper clips, two screws, and a battery. Scrape the insulation off of one side of the wire where the brushes contact it.
Make an electro-magnet (hanger wire core, coil of wire around core, with battery), blow gun (metal tube), dart (cone of paper around a nail). Complete the electo-magnet circuit by way of a wire crossing a flap of paper at the end of the blow gun. Hang a target (stuffed Monkey) from the electro-magnet. Ask the students where you must aim. Above, at, below the monkey? Blow hard and then soft through the blow gun to hit the monkey. Jack Netland did this in my High School physics course.
You might also talk to the "Physics Force"
http://www.imdb.com/name/nm2679312/
http://www.mrsec.umn.edu/ehr/pforce.shtml
http://adsabs.harvard.edu/abs/2005ASAJ..118Q1863L
http://www.physics.umn.edu/outreach/pforce/meettheforce.html
Disclaimer: Jack Netland of the "Physics Force" was my high school physics teacher.
There are a lot of simple passive circuits, but no one is impressed by the switch and lightbulb, or the 1000 variations using solar cells or LEDs.
So, It seems to me that as a physics teacher, your probably better off focusing on the analog side of things and sticking with simple R/C/L type circuits. That stuff is fairly basic and matches up with basic physics. It helps to have some calculus to understand capacitors and inductors, but I understood basically how capacitors and inductors worked, long before I took a formal calculus class. Any good teacher should be able to impart a basic knowledge, its like computing the distance/speed/acceleration without doing the calculus, you just give the students the final formulas and an explanation of how to work them. Making the parts may or may not save some money, but it imparts a hands on kind of knowledge that isn't often taught in school.
Some ideas,
The real problem is that the excitement level is going to be fairly limited, unless you add a BJT or FET. If you add those, the sky is the limit. Again the math can get pretty ugly, but running a BJT as a switch between saturation and cutoff is easy to understand and opens up the possibility of building simple and/or gates. From that you can build a bunch of digital stuff. Radio shack sold 100 packs of 2N2222 BJTs for just a few $ back when they sold such things. I'm sure you can find similar deals if you hunt around.
That said, again your probably better off sticking with the analog, the results tend to be more impressive due to the limited parts count. I would stay away from IC's. I don't think they are appropriate for a basic physics class as they are just black boxes. Plus, they can be expensive in the quantities you will need.
Finally, if your making the components, its going to be very helpful to be able to measure their capacitance, resistance or inductance. An inexpensive meter can provide R/C measurements, and you can build circuits that a part can be dropped in, that counts frequency or measures inductance.
Make all those 'dead' batteries run little torches:
http://www.emanator.demon.co.uk/bigclive/joule.htm
No sig today...
Two words: :)
Joule Thief
-The kids get to play with electromagnetics (wind their own transformer) and see how very simple swichmode converters work. All for a very small outlay of parts, esp in quantity from someplace like digikey. Plus it's a way to drain some more joules out of batteries that are prob too dead to do anything else with
Whee!
Starting out with series and parallel circuits with simple resistors and lightbulbs are a good start, but they're pretty easy to pick up on and notice. It all really depends on how in depth the teacher needs to get or wants to get. If it's just to get them to better understand the complex workings of the equipment they're going to be programming with, it's not going to be necessary to get to the fine details. Besides, why deprive them the joy of transistors (analog) and logic gates (digital)? That's where a lot of the fun (and headaches) begin!
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.
More
I have recently put on a IEEE Teachers In Service Program (TISP), where engineering students, usually grad and undergrad, go to local elementary through high school class rooms to inform teachers about lesson plans, such as ones you are asking for.
The best news for you is that it is almost fully subsidized!
Here are the some of the lesson plans. I would greatly recommend you look into the program, as I really enjoyed being able to bring teachers new material that got their classes excited about engineering and science.
How about a power supply they can use to charge their small devices? All you need for a basic power supply are a transformer, some diodes, resistors and capacitors. Or a small voltage divider bias BJT amplifier? a couple capacitors, an NPN transistor, and some resistors. Could be used to amplify music coming from an iPod and show the principals of amplification.
With which to annoy friends, parents, and younger siblings.
With reasonable men I will reason; with humane men I will plead; but to tyrants I will give no quarter. -- William Lloyd
Circuits for this abound on the web and in ham literature. The project should be well under $5 with a bit of home scrounging (medicine bottles), and they could provide their own headphones. BG Micro or All Electronics are just two surplus parts companies with cheap stuff.
they could tune in to international broadcast, and it would be lots of fun, something they would keep, and something they could show off to their friends.
Dick Smith (if they are in the us, maybe something similar) sells kits with full instructions. they need to be soldered, but year 9s should be able to do this - I had year 8s solder successfully. they will need to be reminded of first aid treatment for burns first. they can build light detectors, movement detectors, radio recievers, sirens, simple electric pianos etc.
I agree with previous posters: the Arduino, opamps, and 555 timers are a good entry point into the art and technology of electronics.
But the really fascinating physical phenomena are buried inside a plastic capsule.
How about refocus the goal around working with a fundamental physical phenomenon and then deploy some simple instrumentation?
PN junction electronics:
I have some metal can transistors where I sawed the can off and looked at the junctions with a 10x hand lens.
Photo transistors are really neat gadgets. I have played with them and wished I could get a little closer to the junction physics. Is one incoming photon actually releasing one electron at the junction?
How about playing with the copper-copper oxide junction? It is the original electrical mystery phenomena that led to solid state physics.
I learned a lot by hanging a transistor and some current limiting resistors and using a voltmeter to develop an understanding of what is a "current amplifier".
There was a lady at MakeFair who demonstrated making FET transistors and photo cells with a tabletop ceramics kiln, some $4 wafers bought online.
Bridges and revisiting the problem of finding the first fundamental units.
How about a Whetstone bridge? It is the classic device for measuring things. As an extra credit project: see if any of the kids can solve for the exact current through the cross leg when the bridge is unbalanced.
Projects built around interference rings. I have tried building an inferometer using a solid state LED laser and I couldn't convince myself I was seeing diffraction bands nor interference patterns. So I didn't try to do a Michaelson inferometer.
How about see if you can use a monochrome LED with microscope slides to make interference bands? Measure or weigh something with the resulting device.
I used the Tab Book "Electronics Self Taught" which suggested a 4" x 8" plywood board with 4 nails and two strands of bus bar wire to make a prototype board. Tack solder pieces and let everything hang in the air.
Dr. Betty Lise Anderson at The Ohio State University has used her senior design class to develop projects aimed at that exact age group: http://www.ece.osu.edu/~anderson/outreach.html
Many years ago (and I hope the articles can be found), Scientific American had an article or short series on how to make some fun projects out of a simple and cheap (especially cheap these days) transistor radio.
While not at all in-depth about the electronics (the radio is basically treated as a black-box amplifier), the article(s) showed how to solder two wires to the volume control, in order to access the input stage of the amplifier. Just about any sort of input can then be amplified.
A simple capacitor (combined with the variable resistance of the volume control) can make a variable tone generator.
Adding a series capacitor to the input allows connecting to (tapping) a telephone line without destroying the radio, by filtering out the DC component present on the telephone line. (Ringing signal is ~60 volts, and IIRC the voice signal is around 12 or 24 volts.) This is not a practical "telephone tap" of course, no worries there, because it places a load (and a bit of noise) on the line and so its presence is easily detectable.
Connecting the input wires to a solar cell (especially if placed at the focus of a parabolic mirror), allows you to listen to voices in a (relatively) distant building by catching sunlight reflected off of a window. The light is modulated by the vibrating glass.
Alternatively, connect a dynamic microphone to the input wires, put it at the focus of the same mirror, and listen to birds chirp at a considerable distance.
As I mentioned, these experiments do not focus much on the electrical circuits per se, but they do teach some basics, they are lots of fun, and they include some other scientific principles as well. If they raise an interest, perhaps the goal is accomplished.
At $5 each, there are few options. Rainbow Kits are a possibility. The "blinking lights" and "1W audio amplifier" kits are both under $5.99. That's about as low as you can go.
Find some copies of the "Engineer's Notebooks" and "Mini Notebooks", by Forrest M. Mims III. These used to be available at Radio Shack, but as far as I know they are now out of print.
(All is not lost, however: they can be found here. I have no idea if this source is strictly in conformance with copyright law or not. I make no promises there. I am just pointing out a source I found.)
Most of the projects shown in his notebooks can be built for a few bucks at most. And once you do a couple of transistor projects, I highly recommend his "Engineer's Notebook II: Handbook of Integrated Circuit Applications". The projects in that book are surprisingly simple and inexpensive, and will give your students a little background in using more modern circuitry, up to and including digital circuits. For example, it shows how you can make two separate oscillators using a few resistors and capacitors, and a CMOS Quad NAND gate chip, which can cost as little as $0.25 in bulk.
I would like to offer a little advice about the integrated circuit projects, however: (1) Stick with the CMOS circuits. Nobody uses TTL anymore. CMOS is very forgiving of supply voltages (tyically you can supply your projects with anywhere from 3 to 18 volts, a 9V battery works great), and consume very little power. The older TTL uses strictly regulated 5V higher-current power supplies, and get hot. Like I said, nobody uses TTL anymore. And (2), you might have to order the chips, since many Radio Shack stores do not carry them on the shelf anymore (although you might find some there). But they are not difficult to order. You can probably order them from any Radio Shack. Most of the chips should not cost you more than $0.80 to $1.00 each, and other than the battery, most of the projects in his handbook consist of just a chip, a couple of capacitors and resistors, and maybe an LED. Dirt cheap, all of them, but very instructive.
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
Join an organization like FIRST (http://www.usfirst.org/) and get corporate sponsorship to improve your budget.
I've just recently graduated from high school, and just finished co-teaching a grade 10 computer engineering class (it's a cool program, senior students help teachers teach junior courses).
Anyways, one of the cooler cheap projects we found was building a rudimentary taser from a disposable camera. They cost about $5 (or cheaper if you buy them in bulk), and the ones we used got up to about 300 volts (good zap from that one). Sure, there are concerns of safety (one kid zapped his dad in the neck... and well, things went downhill from there), but it's an easy, quick project that let's you get involved into more interesting electronic components like capacitors and transformers (instead of the standard resistor, diode, and LED). You can even talk about how the amperage becomes minimal as 1.5 volts from a battery is stepped up to 300 volts.
Plus there's an instant cool factor to building a taser. From personal experience, the grade 10's loved it.
Why not go to http://www.dubli.com/ and buy the parts there? The shopping mall is full of cheap bargains. Buy something, rip the motor out, buy something else, use the frame... the list goes on. Or even better, just buy something new and fiddle about with it and then claim it as your own. With DubLi, it's all possible. Why? Cos it's cheap :)
Use the dead bug wire wrap technique: hot glue the components onto something, or to each other. Use a wire wrap tool and wire to connect leads as appropriate. This works well with everything except surface mount components.
A small FM transmitter could be done for $5. google for FM transmitter/microphone/bug for schematic. Stick some nails in a wooden board a few cm square to solder components to. Use trimmer capacitors with cardboard knobs glued on instead of large tuning capacitors. If you are in the US, Jameco is a good supplier: microphone is about $1, trimmer cap about $0.50, everything else probably less than $0.50. Get batteries wherever you normally get them. Cheap generic 9V batteries are about $1.50. Crystal radios are great, put the problem is the piezo earphones, I don't think I've ever seen them for less than $5, but if you can find them for less, a crystal radio is a great project.
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I'd suggest building some things that are "useful" or "fun" as assembled units, not just "useful" from the standpoint of learning electronics theory and "fun" as a craft construction project.
There are several types of radio receivers you could build as others have suggested, anywhere from a crystal set to a heterodyne AM receiver. It wouldn't be impossible to use some "radio on a chip" integrated circuits and even make a functional advanced AM/FM type of unit -- often they need very few external components to work.
There are radio transmitter options too -- you can inexpensively buy the sort of devices which are used to lock/unlock cars or open garage doors, and use them as a remote control sort of device. You could also build a simple morse code transmitter / receiver -- look at the "pixie" [google] type of projects on many amateur radio web sites; you could build one for cents worth of components with a little improvisation for the enclosure (tin can, altoids tin, ...).
Consider getting a little microphone and speaker and LED and photo transistor and make a little op-amp infrared beam voice transmitter radio. With the prices of cheap surplus microphones and speakers, the total cost should be under $3/unit easily.
Try an op-amp and microphone and speaker and make a little mixer / oscillator based pitch shifter.. you could shift the pitch of your own voice up or down or you could shift the frequency of ultrasonic frequencies you could not normally hear into audible frequency ranges and be able to hear bird calls, bats, moths, crickets, air hissing, running water, etc. producing sounds that you'd never normally hear.
Make a digital compass using a fluxgate magnetometer type of circuit, can be done very cheaply with mostly surplus parts, a transistor, maybe a small microcontroller to assist with the waveform generation and measurement.
Use a microphone and a sound cup and an op-amp and a speaker to make a digital stethoscope and use it to listen to things like breathing, heart beats, sounds of machinery, etc.
Find a new use for an old stereo amp and maybe a little microcontroller and make a proton precession magnetometer.
Take apart a "body heat" type of infrared security detector (very cheap as junk/surplus), contrive a simple mechanical scanner system for it, and hook the output to a PC for image display and take some crude thermogram pictures.. I think I saw an article like this in makezine or one of those sorts of places lately. Trivial circuitry, mostly just needs a little ingenuity at making a radial-theta type of "turntable" scanning mechanism. I bet the shop teacher would make a few as a combination project with you.
Use some junked / cheap aluminium salad bowls or similar and put a microphone in them acting as a dish, hook up an op-amp and speaker and make some directional high gain microphones... see if you can hear a whisper at the end of the school hallway or the ticking of a clock across the room or point it out the window to listen to traffic, birds, airplanes, whatever. Very low total cost / complexity here, lots of fun going around listening to environmental sounds.
Take a microphone, op-amp, 3.5mm stereo headphone cable/plug and connect an microphone audio amplifier to the sound card input of the class PC. Use free software to show oscilloscope and spectrogram (fft/waterfall type of display) types of displays. Identify bird calls by their spectrogram. Look at different people's "voice prints" in spectral display as well as the o-scope style wave form of their voices in the time domain. Look at a heart beat waveform spectrogram from the stethoscope type of microphone pickup placement.
Use a microcontroller with an ADC built in in addition to a serial port or USB type of output and hook up some simple low cost op-amp circuits to electrodes and show how you can capture EKG or EEG waveforms of the heart / brain waves from electrodes on the skin.
For parts, check places like goldmine electronics surplus "the
Just set up a bunch of simple logic gates. Use a bunch of ANDs and ORs and LEDs. You can get all these for under $5 and while it is simple, you can introduce some advanced concepts.
Then move on to a crystal radio. Show them the math behind the design of the inductor, how you calculate the number of turns to make the circuit resonate at the required frequency.
I've been involved in this very topic for quite some time. One of the best idea's we've come up with is building your own solar cell from LEDs.
So drop the traditional ICs from radioshack etc -- "logic gates", or old-school 555 timers, TTL, etc like previous post suggest (no one uses these in real life -- and they are very uninteresting from an academic standpoint).
If you want to teach the underlying PHYSICS, why not teach them about PN junction directly?
How?
Use A LOT of LEDs.
One great experiment is to only use LED's + a breadboard + light source (sun?) + NO power source ==> you can create your own solar array with a bunch of LED to power a single one directly with sunlight. how? well, expose a PN to light and suddenly current is generated. simple, but there is a lot of stuff going on here.
then you can start incorporating other stuff, like a capacitor to store the charge, who knows, maybe an RC element to create a timer, something simple. basically have them design from basic components instead of buying useless ICs from radioshack.
You wouldn't believe how many "problems" posted in microcontroller forums can be narrowed down to the OP using an RC reset "like shown in the datasheet".
According to similar experiences that I've had with tween/teen students, I'd strongly advocate by starting off with the anology based explaination of the two most wonderful things(or perhaps one) out there, the Diode & the Transistor.
Tell them about the various uses they can put these for, and build a simple circuit or two. Wont cost you a lot, and probably everything else mentioned above would be an extension of it.
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.
download the freeby graphical spice simulator from here: http://www.simetrix.co.uk/ I use this at home and I use the licensed version professionally at work. Its pretty easy to use and its great for teaching them fundamentals of electronics. While its no substitute for building circuits in hardware, its a great tool professionally for trying out circuits before prototyping and then optimising them afterwards. In a school environment, this would be a good way of teaching them some basics of current, voltage, frequency etc etc, without spending lots of money on things like oscilloscopes, spectrum analysers etc. That said, being able to drive a scope is a useful skill in itself.. just wish the manufacturers would get together and standardise the controls! :-p
where we cut open pennies
OMG. I read that as "cut open penises".
Squirrel!
It turns out that you can measure Planck's constant, one of the fundamental numbers that define the universe, with a few LEDs and resistors and a small voltage source.
http://www.google.com/search?hl=en&q=led+planck's+constant
(Although the physics is really a little tough for 9th graders. :-)
Try search the internet.
When I worked at Micron Technology in Boise, ID, we had a volunteer program that would go into the classroom to teach about basic circuits. Using a breadboard, transistors and a few LEDs the kids received a fun, hands-on introduction to electronics. I participated a few times and had a lot of fun, especially since the company was paying for a day out of the office. And, as far as I know, the teacher just had to call up and request the electronics lab. Worth a shot?
Go with a simple transistor audio amplifier. It doesn't have to be anything special, it doesn't even have to sound great. It will, however, teach the basics of how semiconductors work.
It's been a long time.
How about circuits that explain the principles behind the black box microcontrollers that you speak of.
Flip Flops, for SRAM.
Counters, Adding and Subtracting all using either gates or more interesting with discreet components.
This would be pretty easy and cheap to do.
It would require two magnets, some magnetic wire, a battery, two paper clips which are the 'brushes', some copper tape for the commutator, some sort wooden/metal rod to mount the rotor onto, and bigger piece of cylindrical wood for your commutator. This might blow your budget the first year, but i would see the only recurring expense be the copper tape, batteries and the magnetic wire.
Here is a website on how some of the assembly should look
http://hades.mech.northwestern.edu/wiki/index.php/Brushed_DC_Motor_Theory
Look about halfway down the page when describing the theory.
My only pointers would be to make a multi-turn coil of wire instead of a single single. Obviously you will need to add a rotor and commutator, so that is what the various wooden pieces are. Make the copper tape cover as much of the circumference of the commutator, as it will work better.
I found another, simpler DC motor, but it didn't look to exciting. You can search google to find other types of projects.
When I made radios from kits as a young lad, I didn't understand the theory behind the parts, but the memories of building the kits made science come alive later.
Building a kit that is a few years beyond a student's current knowledge boosts their ability and desire to learn when they do have the foundational knowledge to actually learn how the device works.
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
I have seen some pretty awesome looking(useless) motors built out of paper clips, magnets, and a battery. I'm pretty sure there are tonnes of designs on the internet. I think your going the wrong way to expect a 9th grader to understand circuitry and programming. There isn't a lot of basic physics j that can be taught around it.
Dusk to Dawn circuits are simple, you don't have to use 120VAC, and demonstrate several electronic principles. The Thyristors, triac and diac, aren't the most simple to understand but you could substitute a transistor and use it for DC.
Meddle thou not in the affairs of Dragons, for thou art crunchy and with most anything.
On the really simple side.. modify a Cue Cat bar code reader.
Make a really simple headgear doo dad that tracks head movement. Use in race car games/flight sims to simulate looking left and right. The tie in to a game might be really exciting. http://www.free-track.net/english/
It would probably be useful to many people who don't read /. but who do use Google.
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
Logic gates made from transistors (and & or are simple to understand conceptually) would be good projects. If your students can grasp binary numbers, half adders and full adders can be interesting.
The trick to teaching transistors is to forget the math, different modes of operation, etc, and just treat them like a switch. For that matter, you could use relays to substitute for transistors and teach logic gates that way.
Oscilators are kind of cool too, and relatively simple.
Why not a simple op-amp based headphone amp? Like this one: http://tangentsoft.net/audio/cmoy-tutorial/ You can present the simple an Op-Amp model since you only really need algebra to understand how an Op-Amp works at a high level. Plus in the end the kids will have a cool and useful device.
Ok, there are lots of ideas here about what to build. You still need parts to build it out of.
Are you a ham radio operator? If so you probably already know this but if not look for a local Hamfest. http://www.arrl.org/hamfests.html All but the smallest ones usually have vendors selling components at prices very similar to EBay only without the shipping fees. You might not find every part you need for a specific project but you can usually find the majority of them and then you can order the rest later. Often vendors will sell large quantities cheap, sometimes buying a vendor out of an item is cheaper than buying just a few because they don't want to haul it all home. This could work out well for you if you want the whole class to each be able to build their own.
As for a project... In the back of Getting Started with Electronics (another Forrest M Mims III book) there is a little organ that I am kind of partial to. The buttons are the only relatively expensive part. you might find someone selling a sack full of push buttons at a hamfest, if not then you an always use tin strips and screws to make buttons at those power levels. I had an ex-girlfriend some years ago who saw me building stuff and wanted to give it a try. She was in to music and I remembered seeing that in there so I bought all the parts, taught her to solder and she did it. It worked the first try.
Switches, wires, and, if you're really fancy, a perfboard.
I believe, 9th graders want to see cool stuff. Bulbs are nice because they are a way of showing that "something" is working. I think visual or audio signals encourage people as they are seeing the result all the time. So I also agree with you (the parent, not the grand parent) that LEDs would be a good way.
Now as for the question: Physics related to electronics for 9th graders? Tough, my ideas:
I think these would be fun, techie, and an art installation at your school. http://www.metacafe.com/watch/502285/how_to_magnetic_led_sticky_lights/
Cheap, relatively easy to design, and practical to what kids are interested in (loud music). Might even allow them to appreciate clean audio sounds instead of "dude! it's got a lot of bass!"
here's one that we're actually looking to use at the office. jeroen hoppenbrouwers has a great little write up (http://www.hoppie.nl/tempsens/) on building a temperature sensing array. students can build individual sensors for well within your $5 ballpark and the group can assemble the rs232 interface and whatever housing you decide to go with for just a little bit more. everything rolls back through the serial connector to an antiquated chunk of x86 hardware that you get from it department is getting ready to throw out. pick your favorite linux distro, install digitemp (http://www.digitemp.com/) and you're ready to start gathering scads of data for use with nagios (http://www.nagios.org/), cacti (http://www.cacti.net/) or your favorite rrd (http://oss.oetiker.ch/rrdtool/) based tool.
kids get to learn about:
-simple circuits
-open source and standards
-the power of cheap, effective systems
-how badly the building needs hvac work
-start to finish application of multiple layers of technology
Have them build a clock radio, with alarm. Lots of digital logic, cheap. A breadboard is useful so as to avoid soldering, and some kits to go with the breadboard (little wire segments). If you make them run it off of wall current, they'll have to learn how to go from AC to DC. Might take a few months of working in groups to do, but you can learn a lot that way.
I would suggest a project that is simple enough to understand, yet has a demonstrable practical circuit that they may choose to use after the class is over. One idea that quickly comes to mind is a simple (2-3-transistor or 2-3-per-channel (stereo)) audio amplifier, suitable to powering a small speaker, with a jack to connect to MP3 player.
It demonstrates one of two basic modes of operation for transistors, one of the most important semiconductor devices (diodes and ICs are others) that is a building block for analog (and digital) electronics. The other mode is when the transistor acts as a switch BTW.
You can cover electron and conventional current flow, waves (sound), and feedback as physics topics.
For the parts, using a mail-order suppler like Digi-Key, Mouser, or Jameco (US / Canada) you should be able to buy the parts for about $5 including the connector and a small speaker.
See Simple 3 Transistor Audio Amp (50 milliwatt) from Bill Bowden's hobby circuits web site.
Make them build some simple AM emitter and receiver. It's always fun to ear some pals voice on the other side of the wall using radio :)
For more advanced projects:
I highly recommend that you give each student (or team of students) a bread board and a reliable power supply and multimeter to work with. These things don't have to be too expensive (e.g. scrounge for unused wall-wart power supplies and tack on a 5V regulator), and they will help the experiments go smoothly.
A simple timer. Crystal with frequency divider using sequential logic (a few flip-flops) for the time base. Some combinational logic using buttons to control the timer. You could consider buying FPGA dev kits and make teams (so the cost is lower), to have more advanced features.
Personally, I started understanding computers when I saw how an adder worked, at the gate level.
Just give them a regular vibrator and some chicken wire, and wait and see who comes up with a working CD player...
Crystal radios are amazing, use cheap parts, and can teach you a lot. Add a single transistor amplifier if you want more volume.
Way too any intro electronic "experiments" are either underwhelming (I lit an LED!) or black box magic (Build a radio transmitter by following these 37 simple steps! The following paragraph explains how the circuit works...). So I sympathize with the original request. Personally, I think the trick is to use a low end microcontroller and some cool I/O, and get the kids doing some simple, minimal programming so that they feel ownership. The best answer to this used to be a Basic Stamp, but the cost is prohibitive. Doing this on a budget today, I'd probably get some low-end 8-pin PIC, some switches and lights, and a cheap servo motor (one of the sub $4 HXT ones from HobbyCity). Then I'd have the kids share a few PC's loaded with MPLAB (free) and maybe a cheap Basic or C compiler (there are free ones). Finally, you'll need a cheap programmer (a PICKIT 2 or a third party one). It's a bit more work, but that's enough for the kids to do some really cool stuff. The goal here should be to give the kids tools so that they can be confident enough to go off and make their own cool stuff. To get the flavor of some of these ideas, check out: http://aggregate.org/hankd/piaee12.pdf
I attended the Microcontroller Monday classes at the local hackerspace, HacDC (http://hacdc.org/) where we worked from plans found on Lady Ada's sites (http://www.ladyada.net/make/usbtinyisp/ and http://www.adafruit.com/).
The other thing to do is get started with US FIRST Robotics (http://www.usfirst.org/) established by the inventor of the Segway, Dean Kamen to "inspire young people to be science and technology leaders, by engaging them in exciting mentor-based programs that build science, engineering and technology skills, that inspire innovation, and that foster well-rounded life capabilities including self-confidence, communication, and leadership." according to the web site.
The logic engine here wants me to say more. I've no more to say.
Cranky educator.
Worth mentioning a TED talk that's spot-on. Cliff Stoll (well known to older Slashdot readers) teaches physics to 8th graders, and his students used an old oscilloscope to measure the speed of sound.
Check out the talk at http://www.ted.com/talks/clifford_stoll_on_everything.html
Wish I'd had a teacher like that.
http://www.nerdkits.com/
Unfortunately meets all the criteria you set forward except for the price one, which I feel may be your greatest limiting factor.
Perhaps a round-robin approach with one kit. Pair students into groups, and give each group a time-slot with the kit?
I really hope you manage to pull this off! I wish any of the teachers in my high school would have had the ambition to try and teach me and my peers this stuff at such an early stage in the game.
You should be able to pick up basic components on the cheep or free if you scrounge, I'm talking old can transistors, LEDs and resistors. You may also be able to lay hands on some project boards by asking around for donations.
With this box and some batteries each student should be able to make basic logic circuits. That is, Have them actually make a flip-flop. Have them get together and hook up their individual flip-flop circuits into gates. This gives them an appreciation for what digital logic does and how to combine it to make more complex circuits. You also get an opportunity to discuss state logic and have them make simple state machines other than flip flops. (adder, counter, timer...)
What they're learning for this physics module:
Ohms law (biasing the transistors)
Semi-Conductor materials science
Why different kinds of transistors need to be
hooked up in different ways to do the same thing.
Interface Design (how to make it so their circuits work together)
Digital vs Analog logic (review of pre-digital systems)
It's cool, re-usable, relevant to their world, and you can complete the module in less than a week.
Useful, practical, and educational. It's more of a power source, though technically I suppose it is a circuit.
http://en.wikipedia.org/wiki/Stirling_engine
When I was in 9th grade, we made AM tuners! I remember making the coil by very carefully wrapping copper wire around a cardboard toilet paper tube. That was kind of fun.
I was in high school at the time the first medium scale ICs were coming into use.
We had a optional class in electronics that worked like this:
Two days a week the teacher would lecture.
Three days a week we worked in the lab.
The lab manual had about 40 projects in it, and a tree of which projects had to be done before other projects.
So for example: the first project was to build a voltage divider. Two resistors.
Another basic project was to determine if a transister was a PNP or NPN.
A third that depeded on both the above was to build a simple biased transistor amplifier.
Dr. Ingerson, our teacher, gave us schematics, but didn't put values on them. We had to work out what the values should be from the content of the lectures.
By mid term we were making bistable flip flops, multistable flip-flops, one shot flip flops.
By doing it this way the need for exotic equipment was minimized. While everyone needed a VOM, we could get by with only a half dozen signal generators, a similar number of oscilloscopes, a single transistor tester, a single high frequency oscilloscope etc. Of the 40 projects you only needed to do, I think 20. And after the bottom 10 or so, there was enough scope that not everyone was doing everything in lock step.
If you needed one of the special pieces of equipment you sat next to it. In this way, 2-3 people could use the HF oscilliscope, check something, and dig into their circuit to fix things while the next guy used it.
Some of the projects helped with equipment. One, for example, was to sort 100 random resistors into the parts bin. At that time you could get floor sweepings for about a cent each. By the time you had done a hundred, you knew the resistor color code -- and also NOT to believe the code.
Another was to sort a batch of 20 transistors by beta using the transistor tester. You had to sort by PNP/NPN Si/Ge and beta at some nominal voltage above the knee.
Another project was to make an electret -- the electrical equivalent of a magnet. And then demonstrate that you had made one by measuring the field with a free gate mosfet.
Photocell controlled circuits.
Op amps.
Now you could easily do a project to transmit your voice down the hall with an LED and photocell.
All the projects were breadboarded with spring loaded wire clips. It meant that quick cut and try circuits were possible. We were expected to keep a note book. We had no guarantee that the circuit would be intact at the next class, although usually they were.
Each project had defined goal: E.g. We used old car batteries with a circuit breaker for a lot of our power supplies. (A car battery would hold *some* charge long after it's too tired to start a car) So that first project would have as a defined goal, "Produce a voltage divider uses a car battery as source, and delivers 5 volts. You should be able to pull 200 mA without droppnig the voltage by more than .5 volts."
Ingerson taught us 'model making' It was critical to have a mental model of how the circuit worked. When things didn't work as expected, he would say, "Your model doesn't match reality. Check your model" And we'd start measuring voltages and got to quickly find out that the triple orange 33K resistor was actually and infinite ohm resister. (Or as
Wally Russell my classmate commented, "It's a dual pack monode")
It was one of the coolest classes in high school.
I'm not sure if grade 9's as a group are ready for it. My experience is that 9's would have trouble with the level of abstraction. Oh, half would do ok, but the other half would have trouble.
If I were teaching science to grade 9's and lived in a climate that had more than "winter" and "August" as seasons, I'd do field ecology. Trap and band mice. Do population studies. Migration & territory studies. Habitat studies.
Third Career: Tree Farmer Second Career: Computer Geek First Career: Teacher, Outdoor Instructor, Photographer.
When I volunteer-taught middle schoolers electronics, we used 74-series small-scale-integrated circuit chips with breadboards and colored jumper wire from Radio Shack. http://en.wikipedia.org/wiki/Breadboard The 7447 binary-7-segment decoder gives a lot of bang for the buck, but is tricky to hook up. The circuit we made was 4 bit ripple-carry binary adders, which we daisy chained together at the end of the term.
I know you said you were looking for something more electronics, but for Physics there is no reason not to just stick with stuff that is the most fun and engaging: real hardware, and things that do something physical or make a sound. A lot of electronics projects are just tedious whereas movement or sounds give great feedback!
Everyone loves taking old CDROMs apart. Connect a LED to the motor and pull the drive in and out - very satisfying, cheap, simple and easily leads to discussion of physics. This video has some fun things to try with a small motor: http://www.youtube.com/v/WnWJki-zwsE. The most consistent positive response I have had is playing with the tray on old CDROMs using a battery to make it go in and out - kids and adults get a real kick out of it! They love the gear mechanisms too!
Personally I feel more can be learnt by pulling something familiar apart - many people have never had the opportunity to pull apart something and understand the workings. Even better if you can use the parts in some simple manner (for some reason using a *real* part from something else is more exciting!). Making something from new components is often simplified to the point where it is too detached from obvious real world usage, and loses the interest of students.
I would hope you can find a suitable source for recycled bits; we have a local computer recycler with cheap stuff - boxes of old speakers from PCs, or boxes of old CDROMs, etc. But small motors and speakers can be bought cheaply.
I also love self-made bolt+wire electromagnets (a favorite classic), speakers + sound sources, switches, relays, and potentiometers.
Anything to do with sound just engages. I have just had play with a speaker and 12V - fun sound with metal surfaces! Sparks are awesome if you can supply them - votage and a speaker (or motor inductance) is enough ;) The pencil line and speaker idea in another post was interesting, but probably needs to be amplified (I just measured an HB pencil line as 10's of kOhms for a multiply overdrawn dark line) - beautiful example of resistance though.
Happy moony
http://arduino.cc/
Multiple variations and suppliers
Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software. It's intended for artists, designers, hobbyists, and anyone interested in creating interactive objects or environments.
Arduino can sense the environment by receiving input from a variety of sensors and can affect its surroundings by controlling lights, motors, and other actuators. The microcontroller on the board is programmed using the Arduino programming language (based on Wiring) and the Arduino development environment (based on Processing). Arduino projects can be stand-alone or they can communicate with software on running on a computer (e.g. Flash, Processing, MaxMSP).
Karnaugh maps as the intro to basic electronics?
As many people have said, have fun with 555 timers & LEDs etc.
We once mixed the electronics with the metalwork/woodwork class - the kids had to put their name in a metal sheet either via drilling, punching etc., mount this on the front of a wooden frame and then make it progressively light up using a 555 timer circuit and a 4017 decade counter - first driving just LEDs and then scaling up the project to use SCRs and neon lamps. At the lower end (555+4017+LEDs), this should stay close to the $5 budget and is more fun the Karnaugh mapping!
Sound-to-light is also fun, cheap, entertaining and fits with the music-driven generation - a few RC filters and some SCRs & Lamps or drive a few sets of high-brightness LEDs to avoid mains stuff.
AT&ROFLMAO
Try the Interior light extender. Fun, simple and actually useful, I used it for years on my older cars (Modern ones tend to have one already). You don`t need the PCB, the 2N3055 is robust enough in the TO3 package to mount the other components directly on the transistor (Or use a breadboard). Wrap it in electrical tape, connect it to the door switch and leave it in the kick panel. This one is funky as other types of this actually draw power when not in use, this one does not due to the discharging cap. http://cdselectronics.com/Kits/light_ext.htm