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Low-Budget Electronics Projects For High School?

Posted by timothy on from the does-school-policy-rule-out-ieds? dept.

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?

65 of 364 comments (clear)

  1. A-stable multivibrator by yoshac · · Score: 5, Interesting

    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

    1. Re:A-stable multivibrator by TheGratefulNet · · Score: 3, Funny

      Astable multivibrator

      don't you have to be over 21 to buy those?

      --

      --
      "It is now safe to switch off your computer."
    2. Re:A-stable multivibrator by tylerni7 · · Score: 4, Informative

      There is a great little circuit for something called a "Drawdio" http://web.media.mit.edu/~silver/drawdio/ that kids really love, basically it's an astable 555 that makes a noises with pitch proportional to how long they draw pencil marks. (it's a bit hard to explain quickly, just try the video on that website)
      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.

    3. Re:A-stable multivibrator by blincoln · · Score: 4, 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. 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.

      --
      "...always new atoms but always doing the same dance, remembering what the dance was yesterday." -Richard Feynman
  2. Do they still Sell 100-in-1 kits? by JSBiff · · 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).

    1. Re:Do they still Sell 100-in-1 kits? by Brigadier · · Score: 2, 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.

    2. Re:Do they still Sell 100-in-1 kits? by JSBiff · · Score: 4, 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.

    3. Re:Do they still Sell 100-in-1 kits? by Grishnakh · · Score: 2, 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.

    4. Re:Do they still Sell 100-in-1 kits? by CronoCloud · · Score: 2, 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 to mechanization and also in part due to US industry and government needing as many educated people as it could get.

      People aren't dumber, it's just nowadays it's more than just the socio-economic elite who are getting educations, and getting pressured to go further than their ancestors were. In the old days no one cared if the kid of a sharecropper didn't have an education because for many people, those kinds of people didn't matter. They could just do the same job their parents did.

      Nowadays, that sort of thing isn't tolerated.

  3. 555 Timer by avandesande · · Score: 2, 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.

    --
    love is just extroverted narcissism
    1. Re:555 Timer by avandesande · · Score: 2, Informative

      Getting shocked as a teenager builds character. I should know!

      --
      love is just extroverted narcissism
    2. Re:555 Timer by JackHoffman · · Score: 2, 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 (those which don't work use different modulations and are really uncommon).

      If you're looking for something more digital, building a counter from flip-flops is always instructive and provides the blinkenlights.

  4. A Theremin by davidwr · · Score: 4, Interesting

    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.
    1. Re:A Theremin by fm6 · · Score: 2, Funny

      Now that's a good suggestion. The only risk is that all the students will become fans of really weird movies!

    2. Re:A Theremin by bitrex · · Score: 3, 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. 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.

  5. Nice book by MRe_nl · · Score: 3, Informative

    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"
  6. A simple oscillator by Zaphod-AVA · · Score: 3, 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/

    1. Re:A simple oscillator by harrkev · · Score: 2, 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.

      --
      "-1 Troll" is the apparently the same as "-1 I disagree with you."
  7. Oscillator? by fuzzyfuzzyfungus · · Score: 2, Insightful

    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.

  8. Re:Good Luck by Sparr0 · · Score: 3, 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.

  9. Crystal Radio by typosquatting · · Score: 3, Interesting

    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.

  10. Crystal radio by Mal-2 · · Score: 5, Interesting

    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.
  11. Optical Theremin by micromegas · · Score: 5, Informative

    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 /.

  12. Cost effective? by girlintraining · · Score: 4, 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.

    --
    #fuckbeta #iamslashdot #dicemustdie
  13. Virtual Reality by macragge · · Score: 2, Informative

    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.

  14. Desoldering old stuff? by nizo · · Score: 2, Interesting

    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
  15. Light bulbs and batteries by PleaseFearMe · · 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 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.

    1. Re:Light bulbs and batteries by Smidge204 · · Score: 4, 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=

    2. Re:Light bulbs and batteries by Anonymous Coward · · Score: 2, Interesting

      No offence, but adding bulbs in parallel and series is a bit, well a bit basic. I'm not expert on the American education system, currently only being educated in the Scottish one, but my first year class (10-11), did that sort of thing - and that was science i.e. we hadn't decided on whether to take physics, biology or chemistry. And then when we were in 3rd year we learned the formulas that related to simple circuits and were expected to be able to describe electronics circuits (potential dividers, transistors, relays, light/heat dependent resistors etc.) and how different changes affected them and a basic description of how they worked.(e.g. light up, resistance down, more voltage across R2, high enough voltage for transistor to switch on, allowing current to relay, completing the motors circuit and switching the motor on) Then in 5th year, which I did when I was still 15(last year) - which I believe is about 9th grade - the higher physics course taught what semiconductors were, how they were used and the theory of how MOSFETS worked. So I don't know who moded you insightful, I'd say you were being down right condescending.

      P.S. SciGuy asked about electronics, in first year we were taught that electronics were different to electrical circuits which you proposed teaching.

      Also even though I was in first year only 5 years ago, the course has changed and they are expected to know even more by the end of 2nd year when they start Standard Grades.

    3. Re:Light bulbs and batteries by huckda · · Score: 4, 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

      something fun and useful...a 'hearing aid' =) ... the entire site is useful

      http://www.aaroncake.net/circuits/

      some things more complex...

      http://sci-toys.com/index.html

      fun and educational .. some real easy stuff...and some more challenging stuff...

      Hope this post ranks high enough for you to find it.

      --
      "Just Smile and Nod." --Huck
  16. use an arduino clone by unix_geek_512 · · Score: 2, Interesting

    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.

  17. electric guitar stompboxes? by dunkelfalke · · Score: 2, 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.

    --
    "It's such a fine line between stupid and clever" -- David St. Hubbins, Spinal Tap
  18. Re:Good Luck by tattood · · Score: 3, Informative

    You didnt have a shop class in high school? I took metal shop and got to play with welding torches. That had a much higher potential for getting seriously hurt than a soldering iron.

    --
    WTB [sig], PST!!!
  19. Re:use spice by ocularDeathRay · · Score: 5, Informative

    another option, and I just mentioned him on another story the other day... is take a look at the old forest M Mims III books. They are the books that they used to sell for a couple bucks at radioshack. You can still get them from his website, or a few other places (saw them at Fry's the other day) although they cost a few dollars more now. I started reading his books in the 4th grade and I have worked and played with electronics ever since. Each of his books have schematics (and a guide on how to read them) for many projects which can be built for a few dollars on a breadboard. I would suggest looking at something with a simple linear analog IC like a 555 or 556 timer.

    If you go to jameco.com you can get component grab bags, or my favorite are the component kits. For example the resistor kit has a selection of common values and a nice plastic storage thing that keeps them nice and neat. Give every student a few LEDs from a grab bag, a 555 timer chip, a battery, some jumper wire, a handful of capacitors and resistors from a couple of component kits, and the schematics to make a simple LED flasher. Then the different students will have different values of resistors and capacitors, and will get different results. Then you can time the flashing of each students project and chart the values of resistor, capacitor, and time. Explaining simple RC circuitry is a good place to start teaching somebody electronics.

    The Mims books also get into digital, you could buy some simple nand gate chips and show the students all the different ways to use them, use simple push buttons for input and LEDs for output to save money. It may not be super exciting, but you could build an inventory over a couple years to do something really cool. Use TTL chips, not CMOS because the students will ruin CMOS with ESD. The possibilities are really endless. Any students who really get excited can buy a handful of parts online and build all sorts of neat stuff from those books. There are circuits for opto communications devices, a shortwave radio, a break beam sensor, you name it, its in there.

    --
    Obama is a twitter sock puppet
  20. Scrounge, Circuit Bend, talk to local Radio Shack by CommieLib · · Score: 2, Informative

    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.
  21. Lewin Edwards by larwe · · Score: 5, Informative

    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.

  22. Start with the oldies then move up. by random+coward · · Score: 2, Insightful

    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.

  23. 555 timer by anish1411 · · Score: 2, Funny

    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... :-\

  24. Tagged 'domyjobforme'? Really? by neiras · · 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?

  25. anything arduino by TheGratefulNet · · Score: 3, 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.

    --

    --
    "It is now safe to switch off your computer."
  26. Light + sound + electricity = awesomeness by Sarten-X · · 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-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.
  27. 555 ICs are God. by w3woody · · Score: 4, Informative

    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.)

    1. Re:555 ICs are God. by w3woody · · Score: 3, Informative

      I hit "submit" just as I realized that 556s are a better bet: two 555s on one chip, and Digikey has them for 55 cents per unit, or 50 pieces for $22.

  28. Re:Good Luck by element-o.p. · · Score: 4, 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.

    --
    MCSE? No, sir...I don't do Windows. Yes, I am an idealist. What's your point?
  29. Multimeter by camperdave · · Score: 2, Insightful

    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!
  30. E-Meter by Roger+W+Moore · · Score: 2, 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. 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!".

  31. Re:Good Luck by Grishnakh · · Score: 2, 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.

  32. Build a $5 Van de Graaff generator by cyberfunkr · · Score: 2, Interesting

    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

  33. Have to keep it simple, try RELAYS by rMortyH · · Score: 2, 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!

  34. Light bulbs are old, make a Joule thief... by Joce640k · · Score: 5, Informative

    Make all those 'dead' batteries run little torches:

     

    http://www.emanator.demon.co.uk/bigclive/joule.htm

    --
    No sig today...
  35. Re:NO!!!!! by dsginter · · Score: 4, 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. Introduce the clock and how it can manipulate the states of a digital logic device. Then pick something simple - like a stoplight controller, for example. And then create it.
     
    Using the stop light controller as an example, you have a number of states that can be easily reduced with Karnaugh. Using a basic breadboard and logic gates (not more than a few bucks per head in bulk), the students should be able to design and build the stoplight controller. Use LEDs for a direct representation of the stoplights.
     
    Extra Credit: put in a cross-walk button, corresponding states, Karnaugh maps, gates and LEDs.

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    More
  36. Power Supply/Small BJT Amplifier by sabrex15 · · Score: 2, Insightful

    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.

  37. Re:Good Luck by Savior_on_a_Stick · · Score: 4, 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.

  38. Options at $5 each by Animats · · Score: 2, Informative

    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.

  39. Re:Good Luck by 0100010001010011 · · Score: 2, 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.

  40. Mimms, yes and Bill Beatty and BEAM by Savantissimo · · Score: 4, 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" to teach ages 9-12. To make this learning physics rather than just a craft project, it's crucial to teach the basics before doing projects with complicated circuits or chips. I mean at least voltage, current, serial resistance and parallel conductance using the water-flow analogies, and preferably the divided-pressure tank model of the capacitor as well (see Bill Beatty's "Capacitor Complaints" Also read all his articles about "Electricity" or you will be guaranteed to perpetuate misconceptions. Great teaching ideas there.) This is about as much as you are likely to have time for, but very little interesting happens in circuits without semiconductors, so if you can work in the fluid analogies for diodes (check valves) and transistors the kids will benefit.

    My personal choice for an educational medium-basic circuit project would be a high-pass and a low-pass single-pole filter (both just a capacitor and a resistor). Use a computer sound card as a signal generator and spectrum analyzer using a free program such as OscilloMeter.

    Other good projects would be an H-bridge motor controller (6 transistors) or for something more ambitious a Tilden "nervous net" / BEAM robotic circuit such as a light-tracking head.

    --
    "Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery?" - Patrick Henry
    1. Re:Mimms, yes and Bill Beatty and BEAM by ocularDeathRay · · Score: 2, Interesting

      hi, original mims bringer upper here. I just wanted to say, IANA teacher, but I was lucky enough to have one of those great, life changing type teachers for three years of high school physics. Its my understanding that he is actually very well known among other high school physics teachers around the state and even country. He was a stickler for teaching conceptually before quantitatively, and also for the proper use of words. He would do amazing verbal gymnastics to avoid misconceptions. A frustrating example would be when studying magnetism and you were not allowed to say things like "that marble just wants to sit there", he would point out that the marble doesn't "want" anything. Or the north pole of that magnet "likes" the south pole of that one.... the magnet doesn't "like" anything, and so on.

      I had the pleasure of seeing him teach his advanced second year class 2 times, once as a student and once I was in the room working an independent study, which allowed me to observe it all over again. He taught a couple of months each year about electricity. We learned a lot by making and playing with the electrophorus made of a piece of hard insulation foam, a pie plate, a styrafoam cup, and a piece of wool. We made our own leyden jars out of film canisters, foil and paper clips.

      There was something that he seemed to know instinctively, which I realized the second time I watched him teach the course. The water flow analogies will make a lot of sense to a few of the students. The rest will build misconceptions based on the idea that electricity flows like water (it doesn't).

      I always understood the analogy pretty well, but some were confused. For example, if students were taught one behavior of electricity and how much it was "like water" then they would start to predict that other behaviors of electricity would be "like water". At some point the analogy breaks down and people are saying "but but but, that doesn't make sense".

      I had been playing with electronics since I bought my first iron at 9 or 10 years old. This left me watching other kids in the class trying to learn the stuff I thought came naturally. I could understand water analogies, but most kids in the class would nod confusedly. It finally clicked with me that the ONLY reason I understood the water analogy was that my father was a landscape irrigation contractor, and a farmer. I had been around water flowing in pipes since I could walk. I used to build crap out of the fittings and scrap pipe.

      What you have to realize is that the average high school student knows nothing about plumbing. They know that they turn the knob and water comes out. For previous generations this may have been different. If you grew up a farm kid "changing the water" in the fields like I did, then you might get it. If you were very mechanical and had worked on a radiator, you might get it. But most kids these days grow up playing with electronics instead. You would be much better off explaining water flows in terms of an electricity analogy than the other way around.

      Keep in mind, that in most of the systems where you think of water flowing, it only flows because of gravity. Electricity flows for a fundamentally different reason. I believe the better way to teach electricity is by teaching a simple understanding of the Bohr model of the atom. If you can ask your students to bear with you for a few minutes, and explain that the Bohr model is a good but not perfect model of the atom, just as Newtonian mechanics is a good but not perfect model. Explain to them quickly, and non boringly electrons, protons, neutrons, and the forces involved. Explain valence electrons, conductors and insulators. Then start talking about a simple electrical circuit. Explain it in terms of a flow of electrons (do NOT teach hole flow!) from negative to positive.

      The water analogy does have its place, I just think teachers need to be careful if they think "I will explain it in SIMPLE terms... like water in a pipe". The behavior of water in a pipe i

      --
      Obama is a twitter sock puppet
  41. Re:Good Luck by ocularDeathRay · · Score: 2, Funny

    I don't think I put it in my mouth, THAT time.... lol, don't you love the human brains emergency mode? where it makes sense to stick a burn into your 98.6 degree bacteria filled mouth to "cool it"

    --
    Obama is a twitter sock puppet
  42. Analog vs Digital circuits for teaching Physics by hashwolf · · Score: 3, Insightful

    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."
  43. Using the criteria ... by MindKata · · Score: 3, Interesting

    1) Is fun
    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 ... start with digital on-off operation, then expand to in between voltages, using a potentiometer on its base).

    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.
    1. Re:Using the criteria ... by lxs · · Score: 2, 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.

    2. Re:Using the criteria ... by lxs · · Score: 2, 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.

  44. Hand wound motor by stewbee · · Score: 2, Interesting

    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.

  45. Simple transistor audio amp for MP3 players by plcurechax · · Score: 2, 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, 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.

  46. Sound or Motors.... by QuestionsNotAnswers · · Score: 2, Interesting

    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