Suggestions for projects for a kids' electronics club

[btipton]

Our local library has recently started a kids' electronics club for kids aged 9-15.  I was hoping to get suggestions for projects that would be inexpensive, simple enough for the kids to build on their own, and that would demonstrate a basic concept or how to use a particular component.  Right now, I plan to have them wind their own electromagnets, then we'll let them build a simple LED circuit with a resistor and a switch. 

After that, I'm not sure.  I'm not a professional, just a tinkerer, really, so I'd like to get the thoughts of people with more experience than me.

[Balaur]

When I was younger I always liked to build stuff that I can use or carry around with me, mostly simple circuits with some practicality value.

Some ideas:
- LED blinker with two transistors
- an audio amplifier (the simplest one with an IC first)
- don't know if it's still feasible these days but you can build a simple AM radio receiver. You will need: an exterior antenna (some suspended wire); good ground; a ferrite loop that they can wound by themselves; a big-ass air variable cap; a diode; a transistor; resistors and a speaker. Very steam-punk but you'll love the look on their faces when they will catch the first radio station
- FM transmitter with a microphone
- a rain detector
- an automatic (sunset) light switch
- an electronic alarm using a switch on a door
- some kind of a flashing badge
- you can also obtain discarded electronics and let the kids disassemble them

[Neilm]

One experiment for brothers to do: give an electric shock to someone using a small audio transformer and a pair of AA batteries.

That is the experiment I blame for getting me interested in electronics. (and is one reason by brother is in his company's health and safety board)

Neil

[JohnS_AZ]

Btipton, where abouts are you located?

[FreeThinker]

Hi
Have a look on Ebay and see if you can find a 200 in one electronics kit like this one. http://cgi.ebay.co.uk/Science-Fair-200-1-Electronic-Project-Kit-Rare-/110622311000?pt=UK_Toys_Creative_Educational_RL&hash=item19c19a8258. Then with a little ingenuity you could make your own kits (or bread board individual  circuits) just make sure you get then manual!!.If you get REALLY stuck I THINK I have a photocopy of the manual in the attic I could copy for you, but that will be after Christmas as I'm not going back up there again till we put the christmas deccys away again (It's a real pain in the ass and a bit of a bombsite ).I think Dave did a blog on his 200 in one kit but not sure of the number any one remember? Dave?

[FreeThinker]

Found it (and watched it again  ) ,Happy Days  .Its #54 in the EEVBLOG
http://www.eevblog.com/2010/01/16/eevblog-54-electronics-when-i-was-a-boy/

[Zero999]

A crystal radio.

You could also do some projects made with logic gates then do the same with a PIC programmed with BASIC to demonstrate how complex circuits containing many ICs can be reduced to one MCU.

A ring oscillator demonstration showing how it can be used to produce a 5 phase square wave will flash LEDs sequentially if they're collected correctly. Use the 74HC04 because CD4xxxx gates don't have enough output drive.
http://www.silicontronics.com/index.php?action=ezportal;sa=page;p=27

[btipton]

Btipton, where abouts are you located?

We're in Bristol, Va/Tn.

I think I'm going to make "circuit boards" - small pieces of flat wood with a single component glued to them, with small bolts wired to the component to make it easy for the kids to connect jumpers between different components.  I'll write the symbol and the name for each component on the boards, along with any pertinent notes (like which side of the led is positive/negative).  Each one will be roughly the size of a mousetrap.  I saw something similar in Make magazine, or on their blog.  The nice thing is, the boards will be a good size to make it easy to see what's happening, and the symbols written on the boards will form a schematic on their own. 

[EEVblog]

I second FM transmitters.

Dave.

[Mr J]

Well in our vo-tech we have an exploratory program (9th grade high school) where the student try out a shop for a week. Anyways we use some kits they can take home from Kelvin Electronics http://www.kelvin.com/Merchant2/merchant.mv?Screen=CTGY&Category_Code=ELKIBK . The cheapest kits about 3 dollars. We've looked into making our own kits & PCB's but can't beat there price. We also give them a multimeter http://www.mcmelectronics.com/product/DISTRIBUTED-BY-MCM-72-7940-/72-7940 usually they go on sale for 3 dollars each. We stamp our school and shop names on the meter as well, a bit of PR. We also use some circuits from this book 15629937 EKI Mr Circuit and some basic labs from Heathkit DC Electronics Workbook
   

[Mr J]

here is an FM transmitter we use http://www.kleinisfijn.nl/files/max2606.pdf
It's very stable the only thing it's surface mount, I've made a SOT23-6 to 8 pin dip adapter to solve this so the kids can work with it. Of course you can get free samples form maxim. 
 

[the_raptor]

I think I'm going to make "circuit boards" - small pieces of flat wood with a single component glued to them, with small bolts wired to the component to make it easy for the kids to connect jumpers between different components.  I'll write the symbol and the name for each component on the boards, along with any pertinent notes (like which side of the led is positive/negative).

IMO 9-15 year olds can handle good ol breadboards. That sort of thing might be good for younger kids or for early demos but it is going to involve a decent amount of work to build a big enough selection for a bunch of kids to do some "real" projects. Once kids have a basic understanding there is nothing wrong with breadboards and pre-made jumper wires.

Also have a look at the Make:Electronics book, it has a lot of good ideas for practical demonstrations of electronics (mainly involving self-destructing components and then explaining what happened) and "real" projects that kids can do. I bought it myself as I get enough theory at uni.

[JohnS_AZ]

@Btipton ... PM me a mailing address and I'll send you a couple hundred LEDs and a bunch of slide switches for your effort. It's old stock I'll probably never use.

[Simon]

I second the breadboard, get large ones though so that they don't have to cram circuits together, the parts on a block idea is good but going to be a lot of work and could be a problem with any oscillatory circuit.

You could do some 555 circuits, there are so many functions of the chip and it's all the same chip.

[NiHaoMike]

What about a LED flashlight with a simple one transistor ("Joule Thief") boost converter?

[Zero999]

How much theory are you teaching?

Beware that some simple circuits (Joule Thief, FM oscillator, astable multivibrator etc.) aren't easy to explain to someone without much prior knowledge, let alone a 12 year old.

The 555 is pretty basic but it'll still take a few lessons to briefly explain all the building blocks. A comparator (LM393, LM311 etc.)  or Schmitt trigger (I'd recommend the 74HC14) is probably simpler to explain and is just as versatile as the 555.

[saturation]

Kids seem to like snap kits.  Manuals and theory all included.  Unlike breadboard and spring board kits, when these items are assembled they look like schematic diagrams versus a spaghetti of wires.  These are teaching tools, made to get newbies interested, not to be practical or compact.

[Simon]

the theory will be your problem as Hero said, children want "to do" not sit and learn theory and many things require a fair amount. I used to have one of the 200 in 1 projects things with the spring connectors and the first circuits were just made for fun with no theory, then came lots of simple circuits with just enough theory to keep you going and then some more detailed explanations

[btipton]

First, thanks to everyone for the great suggestions!

To answer some of your questions - I'm probably not going to teach much theory, at least not intentionally.  Kids seem to like things that move, make noise, or light up, so we'll probably do a lot of things involving speakers, relays and LEDs.  The group is weighted towards younger kids right now, so the projects will have to start out simpler for a while.  I'd rather not introduce any ICs until the kids can identify and understand the use of the most common components. 

The younger kids seem to really like learning how to use testing tools - last meeting, they spent a half an hour fixing bulbs in a string of Christmas tree lights using a little hand-held tester.  They loved it!

[Simon]

maybe they will have fun identifying resistor colour codes..... give them a meter and a bunch of resistors at least it is something they will need and use later.

[scrat]

At my school I saw once a panel with Italy map drawing on one side, and many wires on the back. There were a lamp and many plugs on each region and its name, all names written together below the map. You had a wire ended with banana male plugs. If you inserted the two plugs one on the name and one on the matching region, the lamp lit up, supplied by a battery.
The same teacher that built that panel also teached us a little programming with Logo (we were only 6-11 years old!).

Other things I played with were telephone microphones, phones and batteries, with which you can actually build a phone (with such an equipment once we cheated at an oral test at school, the people suggested aswers from the last desk! )

It is also interesting to see that a chain formed by many people hand in hand can be a sufficiently conductive path to light up an LED from a 5V source (the switch can be an arm).

I often had thought about making this kind of things for kids, since I'm a scout chief, but only your question has now unlocked my memory...

[Neilm]

I remember going to a big exhibition many year ago. One of the exhibits used ping pong balls to represent logic signals as they went between gates. The objective was to get a ball down to the bottom and ring a bell. There were about 15 inputs and there was only one combination that worked. There was a small video with a quick explanation of what logic gate did what.

Some years later, I built something similar using  ball bearings, thin tubes, lights and buzzers for a  talk on basic electronics. The ball bearings conducted electricity to light result lights, which then caused small actuators to release a ball bearing to go to the next gate. I had as much fun building it as the kids had playing with it.

Yours

Neil

[Simon]

you could do a finger activated circuit using a darlington transistor with the finger putting current through the base.

[Zero999]

I'd rather not introduce any ICs until the kids can identify and understand the use of the most common components. 

When you do ICs I'd recommend starting with things like logic gates and comparators.

The easiest circuits to understand and use discrete components use relays, transistors as switches and SCRs, but unfortunately they're not the most interesting circuits: burglar alarm, light/dark detector, moisture sensor etc. more fun things such as oscillators, PWM and amplifiers are harder to understand.

[KTP]

How about a transmitter and receiver inside a fountain pen with a pager motor vibrator for output and some sort of subtle switch for input.  This way the kids could "talk" to each other during class without the teacher knowing.  Also, this could be a way to teach them Morse code.