Low-Budget Electronics Projects For High School? 364
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?
A-stable multivibrator (Score:5, Interesting)
Light bulbs and batteries (Score:3, Insightful)
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 t
Re:Light bulbs and batteries (Score:5, Insightful)
I disagree that capacitors and transistors are too advanced, or at least NEED to be taught in an advanced way. The goal is not necessarily to teach them how to design complex circuits, but to get them familiar with the ways the components interact.
Anecdote: I was building projects using transistors and SCRs as early as 6th grade. This included layout and chemical etching of my own circuit boards.
Let's see how many of the projects I can remember doing...
- Soil moisture sensor. Using a cut piece of double sided circuit board as a probe, connected to a small battery operated circuit that measured the resistance between the two sides. When the resistance rose above an adjustable threshold (via potentiometer) an LED would turn on to let you know the plat needed watering.
- "Concentration" game - an SCR and buzzer were used to make a game where you passed a metal loop over a bend metal wire without them touching. Once the two parts touched, completing a circuit, the SCR would latch on and the buzzer would sound until the reset button was pressed. I recall this project also used a voltage regulator.
- "Hide & Seek" game (aka the most annoying thing on the planet. Great for young students!). A set of transistors (4 as I recall) connected with a series of resistors and capacitors would periodically sound a short beep out of a small PC speaker. Duration, tone and period of the sound were adjustable by selecting the component values. As a bonus we were encouraged to find items at home to hide the circuit in - I used a hollowed out video cassette (switch under the flap) and hid in in my dad's video collection, complete with fake label :)
- 4-digit electronic keypad switch. A series of buttons were wired to transfer charge between a series of capacitors, and ultimately to an SCR that would latch a relay to control whatever you wanted to hook up to it. Combination was set by wiring the buttons differently.
- Roulette wheel. A series of LEDs (in a circular pattern) was connected to a small collection of ICs that would cycle them around and stop on one. I honestly don't recall what the ICs were, though :(
- Parallel port PC interface: Control up to eight 120V-10Amp relays via the PC's parallel port. (Included writing "driver" software)
- EQ meter. Build a resistor/diode network that, when fed an (amplified) audio source, caused a row of LEDs to light up according to the music volume.
- Various other blinkenlight projects :)
=Smidge=
Re: (Score:2)
No! "Continue Editing" not "Submit!" Arg...
Please forgive the typos in the above post.
=Smidge=
Re:Light bulbs and batteries (Score:5, Informative)
Deciding I needed a PWM for a project, I wanted to build my own to learn about electronics...so I went to radio shack and bought their $79.99 Electronics Learning Lab.(this kit alone is HOURS of amusement and learning)...but what I learned quickly is that following the Mimms book was very wasteful...the explanations of what is happening is scant...the diagrams are great, but blinking leds and making buzzer noises just ISN'T practical to a freshman in High School(I've taught them Freshman computing and mentored them in many aspects of I.T.)...
Below are some sites I've come across searching for 'simple enough for a basic solderer' and with readily available components(strip parts out of busted old computer power supplies/vcrs/radios/etc)..
http://www.electronics-lab.com/projects/audio/023/index.html [electronics-lab.com]
something fun and useful...a 'hearing aid' =) ... the entire site is useful
http://www.aaroncake.net/circuits/ [aaroncake.net]
some things more complex...
http://sci-toys.com/index.html [sci-toys.com]
fun and educational .. some real easy stuff...and some more challenging stuff...
Hope this post ranks high enough for you to find it.
Light bulbs are old, make a Joule thief... (Score:5, Informative)
Make all those 'dead' batteries run little torches:
http://www.emanator.demon.co.uk/bigclive/joule.htm [demon.co.uk]
Re:A-stable multivibrator (Score:4, Funny)
Astable multivibrator
don't you have to be over 21 to buy those?
Re:A-stable multivibrator (Score:5, Informative)
I teach middle school aged kids electronics at a local workshop, building things such as that, and I can tell you it's very doable to make projects for cheap that kids can build and understand.
The main issues that I have found is the board on which you lay out projects. Breadboards are expensive, and not permanent. PCBs don't allow kids to experiment with their own circuit designs, and unless you are going to take the time and money to let them design their own boards that might not work and then etch them, it's more trouble than it is worth. We use a more traditional breadboard concept that is just an actual, wooden board. Then we have kids use copper tacks and strips to lay down the circuitry, and then they solder things directly to that.
As other people have mentioned, soldering irons are a bit annoying, and a couple kids might get some mild burns, but as long as you don't mind the initial cost, it's totally doable.
One of the great things about the drawdio project, is it allows you to hook it up to a oscilloscope and show the kids more about sound, or hook the piezo speaker up to a computer and run some FFT software, so they can see and hear how the resistance changes the pitch.
Other things to look into are basic transistor circuits, things with opamps, counters, or things with binary to decimal or binary to seven segment LCD chips.
Re:A-stable multivibrator (Score:5, Interesting)
The 555 can be used in a lot of interesting, simple projects. I like the idea of audio, because it's something that (IMO) a lot of young students will find interesting compared to some of the other typical beginning electronics projects.
One very easy 555 project is an Atari Punk Console [hackaday.com]. I built one of those a couple of years ago and took it to a party and it provided hours of entertainment.
Another option might be a simple resonant low-pass filter, since any of the students who've listened to electronic music will immediately recognize the effect and want to play with it.
Re: (Score:2)
not to mention your wife ... or imaginary one there of :)
Do they still Sell 100-in-1 kits? (Score:5, Informative)
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).
Re: (Score:3, Informative)
They still have these but I can't imagine them having the longevity to stand up to ninth graders. After using mine for a few months most of teh spring had become elongated and knobs lost.
Re:Do they still Sell 100-in-1 kits? (Score:5, Insightful)
B.S. Evolution doesn't happen on timescales of 20 years (I'm only 31). Kids aren't any smarter, dumber, or less or more inquisitive, except to the extent that no one has lit their imaginations on fire yet. But, it sounds like this teacher at least wants to *try*. More power to him, and I hope he finds something which fits his classroom needs.
Truly smart, creative engineers and scientists don't need to find jobs - they *create* jobs (often, not only jobs for themselves but good paying jobs for many other people). So, I'm not too worried about America's future, as long as we actually *try* to educate and excite kids about science and engineering.
Re: (Score:2)
Methinks the previous poster was referring to society not evolution.
Re: (Score:3, Interesting)
Evolution doesn't control people's intelligence that much; the way they grow up does. And our society over the past 20-30 years has been in a serious decline.
Re: (Score:2)
Truly smart, creative engineers and scientists don't need to find jobs - they *create* jobs
Um, no. Scientists and engineers almost always work for other people, as employees. Businesspeople create jobs. Scientists and engineers don't have time to create jobs or run businesses. Sometimes they do start businesses, but then they're "former engineers", and can't really call themselves that any more. But since the personality types that enjoy science and engineering aren't the same as the personality types
Re: (Score:2)
Go read Common Sense, the Declaration of Independence, etc and forget about the ideas there. Just look at the vocabulary those guys used. Even Lincoln's or Jefferson's speeches to common people are pretty impressive. Guys like Ted Kennedy or George Bush would be considered mentally retarded by their standards. All the books of previous generations were clearly written for a smarter audience.
The sad fact is that people are becoming dumber and dumber with each generation. Do you really think the average
Re: (Score:3, Interesting)
Jefferson wasn't writing for the common people, since literacy rates were so low, he was writing for other people like him. Wealthy members of the land owning class.
Universal education didn't exist till the late 19th century. My father, born in 1927, tells me that back when he was young it was common for older boys to be years behind their age level in class because they had been taken out of school to help on farms, though he says that sort of thing became less common as the years went by. In part due t
Re: (Score:2)
Are you just bitter? I know plenty of young kids who are really interested in science, even more than I was at their age.
This may be the age of emo, but keep in mind that Generation X was the age of "Whatever."
obxkcd (Score:2)
#603 [xkcd.com]
The only person who is less smart now is you.
Re: (Score:2)
Intelligence has little to do with breeding, and far more to do with upbringing and society. The Dark Ages and Medieval times didn't produce much of value for 1000 years not because people were born stupid, but because the society as a whole didn't value learning or knowledge. The Enlightenment and Renaissance changed all that, and all kinds of great new art, math, and scientific advances resulted. They didn't come from the children of rich people, they came from all over, but they happened because the s
Re: (Score:2)
Nand Gate or Power Supply (Score:2)
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.)
555 Timer (Score:3, Interesting)
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.
Re: (Score:2)
Exposing kids to AC and high-watt light bulbs will certainly result in someone getting shocked with 110VAC. Not a good idea.
Re: (Score:3, Informative)
Getting shocked as a teenager builds character. I should know!
Re: (Score:3, Interesting)
Seconded. I have a very simple circuit for an IR repeater which uses a 556 (that's two 555s in one IC), three resistors, one capacitor, an IR LED and a TSOP 1736 IR receiver. Total cost is less than $5 with a small breadboard, the latter being the most expensive component. One of the 555s is (ab-)used as an inverter. If you don't care too much about protocol, you can do away with that and just have a 50% duty cycle on the output instead of the usual 25%. The IR repeater works with almost all IR remotes (tho
A Theremin (Score:4, Interesting)
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.
You can even make this inter-disciplinary with the music teacher, the English teacher, the history teacher, and the Russian teacher as appropriate.
Re: (Score:3, Funny)
Now that's a good suggestion. The only risk is that all the students will become fans of really weird movies [avclub.com]!
E-Meter (Score:3, Funny)
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 [wikipedia.org]. 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!".
Re:A Theremin (Score:4, Informative)
The problem with the Theremin is that to make a working example based on the principle of the original (capacitive coupling between the hands and antennas changing the frequency of an LC oscillator) is actually a fairly complex project - you have to understand about how LC oscillators work, the superheterodyne principle (the pitch oscillator is the difference frequency between a fixed and variable RF oscillator), transistor amplifier principles, etc. Of course, they can be built from kits, but just building from a kit doesn't really provide any insight into the functioning of the circuit.
A project that maintains the spirit of the original but might be easier for 9th graders to get a handle on might be the optical theremin [instructables.com]. It only uses a few parts, and the basic operation of the 555 timer and light dependent resistance should be approachable for newcomers to electronics.
Nice book (Score:4, Informative)
SIMPLE, LOW-COST ELECTRONICS PROJECTS
http://www.elsevier.com/wps/find/bookdescription.cws_home/677563/description#description [elsevier.com]
A simple oscillator (Score:4, Informative)
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/ [arrl.org]
Re: (Score:3, Interesting)
Another trick is to make it in the audio range, and then have the kids draw a black square on a piece of paper with a pencil. The graphite (carbon) will appear as a variable resistance based on where you put the wires (put one wire at one end and move the other wire around). This will make a kind of crude music synthesizer. All for the cost of a 555, a speaker (piezo is fine), a battery, a battery holder, and a handful of resistors and capacitors.
Oscillator? (Score:3, Insightful)
Crystal Radio (Score:3, Interesting)
Re: (Score:2)
circuit simulation. (Score:2)
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 [electronickits.com]
Two suggestions (Score:2)
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
Crystal radio (Score:5, Interesting)
I'd start with a crystal radio [wikipedia.org], 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 [uoguelph.ca] and some LEDs.
All of these are low power, low cost, and produce a visible or audible result for immediate gratification.
Mal-2
Optical Theremin (Score:5, Informative)
Have them build things (Score:2)
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.
Cost effective? (Score:5, Insightful)
$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.
A few off the top of my head (Score:2)
There's always the good
Virtual Reality (Score:2, Informative)
Desoldering old stuff? (Score:3, Interesting)
What about getting junked electronics (thinking Goodwill here, or possibly even donated) and desoldering components to build other projects with?
Simple LED Lights! (Score:2)
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 y
Literally thousands of projects (Score:2)
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 co
scitoys.com (Score:2)
Check out scitoys.com [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
use an arduino clone (Score:2, Interesting)
Use an arduino clone.
http://www.arduino.cc/ [arduino.cc]
Check out the Rock Bottom Freeduino Kit @ http://wulfden/ [wulfden] ( dot ) org/TheShoppe/freeduino/rbfk.shtml
Link has been edited to prevent the site from getting slashdotted.
electric guitar stompboxes? (Score:3, Interesting)
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.
BEAM robots (Score:2)
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 [wikipedia.org]
A few ideas (Score:2)
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 [amazon.com] is probably stocked with good ideas.
Using a wire wrapping tool [radioshack.com] could be a good way to construct circuits without using solder. You can also use breadboards [radioshack.com]. 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
DSE (Score:2)
Knock yourself out
http://search.dse.com.au/nav/cat2/electronicsandkitsets_kitsets/cat1/electronicsandkitsets/0 [dse.com.au]
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...
LED lighting circuits (Score:2)
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.
Scrounge, Circuit Bend, talk to local Radio Shack (Score:3, Informative)
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.com]
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.
Static Electricity (Score:2)
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.
Lewin Edwards (Score:5, Informative)
Start with the oldies then move up. (Score:3, Insightful)
555 timer (Score:2, Funny)
Tagged 'domyjobforme'? Really? (Score:5, Insightful)
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?
anything arduino (Score:4, Interesting)
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.
Light + sound + electricity = awesomeness (Score:2, Informative)
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-scho
small electronic organ (Score:2)
555 ICs are God. (Score:5, Informative)
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.)
Re:555 ICs are God. (Score:4, Informative)
Telegraph (Score:2)
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.
Don't bother (Score:2)
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.
Metal Detector (Score:2)
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. [easytreasure.co.uk]
The Electronic Goldmine [goldmine-elec.com] 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 componen
Magnet, AM radio, plus others (Score:2)
Might be a bit too pricey. Have your Visa ready.
Crystal radio (Score:2)
Night-light with timer (Score:2)
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.
Multimeter (Score:3, Insightful)
Two quick projects: Data readers. (Score:2)
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.
Have to keep it simple, try RELAYS (Score:3, Insightful)
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!
Power Supply/Small BJT Amplifier (Score:3, Insightful)
Options at $5 each (Score:3, Informative)
At $5 each, there are few options. Rainbow Kits [rainbowkits.com] 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.
Analog vs Digital circuits for teaching Physics (Score:3, Insightful)
Simple transistor audio amp for MP3 players (Score:3, Insightful)
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 [digikey.com], Mouser [mouser.com], or Jameco [jameco.com] (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) [bowdenshob...cuits.info] from Bill Bowden's hobby circuits [bowdenshob...cuits.info] web site.
Re:Good Luck (Score:4, Informative)
I don't think soldering irons are a requirement for this idea. Breadboards, or even springboards, would be much more appropriate, I think. Cost per student goes up, but overhead goes down.
Re: (Score:2)
Re:Good Luck (Score:5, Interesting)
I did something similar, except we were grab assing and I was vaulting my workbench.
My hand landed on the hot iron with my weight fully, though briefly on the hot iron.
Did you immediately jam the burned flesh into your mouth to cool it?
People still look at me oddly when I tell them that fried human flesh tastes a lot more like sauteed mushrooms than pork.
Re: (Score:3, Funny)
Re: (Score:2)
I had a high school chemistry class just a few years ago where we cut open pennies, melted the zinc inside them, and flung the molten zinc out onto the counter. Only one kid burned his hand.
Compared to that experiment, soldering is safe. I would say "as safe as bowling", but bowling causes a fair number of injuries annually.
Re:Good Luck (Score:4, Informative)
Re: (Score:2)
Re: (Score:2)
No, while we had a "vocational" curriculum including electronics, drafting, automotive work, etc. (I don't remember if they had metal shop), we weren't allowed to take those classes if we were college-bound. Only the non-college kids were allowed to take the vocational stuff.
Re: (Score:3, Interesting)
I still want to give a swift cockpunch to my school for that same policy. I'm looking at paying to take a welding class at the local community college so I can work on my car.
Instead I had to sit around and take a Study Hall because god forbid smart people learn to do two things.
Re:Good Luck (Score:5, Insightful)
Soldering has no place in a public school.
Yeah. No one should be learning useful skills in public school!!!
Someone will burn themself, and sue.
As others have mentioned, do you also propose to ban welding in shop class? Alcohol burners in chemistry? Sheesh, you can get a rug burn if you fall down in basketweaving class. A little pain is good for you; pain is a sign of stupidity leaving your body. If nothing else, you learn to be careful with potentially dangerous tools. That is a (TM) Good Thing. Just accept the fact that you can't even get out of bed without accepting some risk and get over it. :rolleyes:
Someone will sue because of exposure to hazardous materials...
RoHS. Use lead-free solder. Problem solved. Besides, I've soldered with leaded solder since I was about tennnnnnn, and I'm just fine I'm just fine.
...or some government agency will get involved.
It's public school -- methinks that, by definition, a government agency is already involved.
Re: (Score:2)
I'm not saying I like it, I'm just pointing out why these things aren't a good idea in today's society.
Re: (Score:3, Insightful)
Yep, but that's what our society has descended to, and doesn't seem to be turning around either.
This over-protective, risk-averse, entitlement-based mentality that our society has developed is going to make Western civilization completely irrelevant in 100 years I think.
Re:use spice (Score:5, Informative)
If you go to jameco.com you can get component grab bags, or my favorite are the component kits. For example the resistor kit has a selection of common values and a nice plastic storage thing that keeps them nice and neat. Give every student a few LEDs from a grab bag, a 555 timer chip, a battery, some jumper wire, a handful of capacitors and resistors from a couple of component kits, and the schematics to make a simple LED flasher. Then the different students will have different values of resistors and capacitors, and will get different results. Then you can time the flashing of each students project and chart the values of resistor, capacitor, and time. Explaining simple RC circuitry is a good place to start teaching somebody electronics.
The Mims books also get into digital, you could buy some simple nand gate chips and show the students all the different ways to use them, use simple push buttons for input and LEDs for output to save money. It may not be super exciting, but you could build an inventory over a couple years to do something really cool. Use TTL chips, not CMOS because the students will ruin CMOS with ESD. The possibilities are really endless. Any students who really get excited can buy a handful of parts online and build all sorts of neat stuff from those books. There are circuits for opto communications devices, a shortwave radio, a break beam sensor, you name it, its in there.
Mimms, yes and Bill Beatty and BEAM (Score:5, Interesting)
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" [amazon.com] 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" [amasci.com] Also read all his articles about "Electricity" [amasci.com] 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 [satcure-focus.com] 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 [corbina.net].
Other good projects would be an H-bridge motor controller [beam-wiki.org] (6 transistors) or for something more ambitious a Tilden "nervous net" / BEAM robotic circuit such as a light-tracking head [beam-wiki.org].
Re: (Score:3, Interesting)
Using the criteria ... (Score:4, Interesting)
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 [talkingelectronics.com]
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.
Re: (Score:3, Interesting)
Why call it a flip-flop when you can give it it's proper name: an astable multivibrator?
A classroom full of sniggers is guaranteed.
Re: (Score:3, Informative)
Non native speaker here. When your Dutch is half as good as my English German or French, please report back. Until then go fuck yourself AC.
Re:NO!!!!! (Score:5, Insightful)
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 [wikipedia.org]. 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.
Re: (Score:2)
Re: (Score:2)