cub scout electronic activity

[MrDEB]

well its a new year for cub scouts and being chief cook n bottle washer I am looking for activity ideas dealing with electronics.
first idea I had was a simple crystal radio (I remember building one years, eons, ago) but the kits and or parts are kinda spend y (more than $10 per) plus here in Salmon we only have one radio station so kinda dumb IMO maybe.
my thoughts were to have the scouts (7-11 year old) build something cool but no soldering. I would solder sockets etc to pcboards
chasing leds maybe activated by placing hand closer (Theremin principle using a pic)
light activated something??
something that makes noise (pic or 555?)
want to try and assemble the kits using spring clips instead of having the boys solder. Plan to etch my own boards (I have about 7-6x9 2oz boards (2 oz is terrible when doing thin traces).
want to keep cost around $5 per or less.
something simple
will consider any and all suggestions.

 

[birdman0_o]

I like the theramin idea! Can you keep it under 5$ thought?

 

[MrDEB]

not sure

thinking of the 555 pocket theremin?? but under $5 ???

 

[stevez]

I would not write off the crystal radio idea so quickly. Maybe you can build one to see how well it might work. I helped my son build one about 20 yrs ago. I've in the suburbs of a midsized city and within 2 miles of a 50 kW AM broadcast station. I was still able to listen to a few of the stronger shortwave stations at night.

Info on clips:
Fahnestock Clips
One of the oldest and most popular terminals ever made. Ideal for
experimental bread-board assemblies where connections are to be
changed readily. Made of brass with nickel-plated finish.

I thought these were obsolete and no longer available. Obsolete was correct but I purchased hundreds of them for $1 at a hamfest.

Another project from 20 years ago - a light listener. More or less a photocell, LM741 amplifier followed by an LM386 audio amp and speaker. With it you could hear the buzz of fluorescent lights, swishing of flame, the scan of a TV set. Was possible on breadboard and parts if purchased sensibly are cheap.

Good luck.

 

[MrDEB]

cryatal radio parts

for ten of each
earphone = $46.54
coil = $19.73
variable cap = $19.04
up to $8.53 per kit
remember these are 7 - 11 year old boys so winding coils is pretty much out of the question IMO
found a sound circuit in Forest Mimms eng note book that looks promissing but need to price out
1-556
2 pots calls for 3 per. thinking photo cells instead of pots?
1 resistor and 2 capacitors, 1 small 8 ohm speaker.
then Fahnestock Clips

 

[audioguru]

The Dollar Store has scanning FM radios with stereo headphones for only $1.00.
The radio is garbage but the headphones are pretty good. The battery might be useful.

 

[stevez]

Yes, the cost is a challenge. If you had unlimted time to shop you'd get better pricing. I had cub scouts for a time and found the same thing.

I would not say that pots could be replaced with photocells - all depends on the application.

 

[MrDEB]

Dollar Store = 200 miles away

$1 for hadphones sounds to good to be true.
I wonder if the Dollar store does Paypal??

 

[MrDEB]

instead of clips = conductive glue?

wonder if white glue mixed w/ graphite would work?
found an instructable talking about using a solvent based glue mixed with graphite
FUMES are a no no

 

[MrDEB]

there is no hurry on this

so yes I can shop around but for which parts for what project.
Yes I like the crystal radio idea but then again we only have one station in a 200 mile radius so a cheap radio will only pickup one station (even some car radios)
thinking about the clever button over at PCBHEAVEN
PCB Heaven
somehow use photocells or photo transistors instead of a button. have several LEDs that flash according to which direction one waves their hand or instead of LEDs have a speaker as per
PIC microcontrollers : chapter 7 - Examples
just some 21st century ideas
going to experiment with the conductive glue

 

[mneary]

Night or evening can be exciting with a crystal radio and no local stations to interfere... but you have to be patient. Patience might not be part of the available ingredients in 7-12 year olds....

 

[MrDEB]

you got that right

just got my two books I ordered on PIC programming and the PICBASIC PROJECTS has a project for an electronic organ using a 16F627 PIC, 8 switches and one speaker.
add a 16F627 then add a a 10uf capacitor to make it sound better.
also has a reaction game timer that looks promising.

 

[Mr RB]

What about a simple BFO type metal detector? So easy to make and only one knob, you can easily tune for wet ground/sand etc.

One of the fun things about camping out as a kid was fossicking around for gold nuggets and old tin cans. Well mainly just cans.

 

[MrDEB]

Nice idea but

remember that no soldering by the boys, too young IMO and they get kinda wild sometimes.
Would think with a BFO having a tuned circuit you would want the parts to have the least amount of variance (conductive glue may not be the best to use in a tuned circuit??

 

[stevez]

I will try to look at my old Radio Shack books (at home, I am at work now). Over the years they (and certainly others) have published some nice, simple projects that are likley perfect for your situation. One of the project was called a cricket - it more or less generated a noise at intervals that varied according to temperature. The noise would be heard on a nearby AM radio.

A project that is more mechanical than "electronic" is a loop antenna to improve AM radio reception. You might blend some woodworking in as the frame is made from wood. More recently a Popular Communications article described an AM loop antenna made from plastic notebook covers. Parts consist of wire for the loop and a 365 pf variable capacitor. You set the AM radio within the loop so no need for connections. IM me if you want more info on this.

 

[Mr RB]

remember that no soldering by the boys, too young IMO and they get kinda wild sometimes.
...

I could solder reasonably well at 10... How old are they? Anyone with the hand/eye coordination to beat level 26 on the XBOX can solder.

But I undertsand if this is one of those "politically correct committee safety nazi" type deals. There's plenty of that going around...

 

[MrDEB]

The boys are 7-10

mostly 7 &8
I have plenty of soldering irons but the safety factor
eyewear and patience.
going to go the conductive glue route along with female headers that are already soldered to the board.
looking at some double row 34pin plugs and 8 ormirom B3W-1052 switches
Omron B3W-1052 - Miniature Pushbutton Switch (pkg 100)-The Electronic Goldmine
The Electronic Goldmine
question is will the switches plug into the header plug??
plan to use the 18Fxxxx PIC (the book has code for 16Fxxxx but should be able to convert.reason = the 16Fxxxx needs oscillator added
speakers = .50 each
battery pack etc needs to be priced out.
hopefully $5 or less per kit

 

[Mr RB]

Hmm ok 7 and 8 might be a bit young for safe soldering.

The pushbuttons in your link won't conform to a 0.1" grid, they use a metric spacing. If you bend the legs they go into 0.1" spacing pcb, maybe you can get them into headers.

 

[MrDEB]

planning on ordering

pretty cheap for 100 push buttons
started reading the book on asm language. Thinking about swordfish, so much easier I think but am just getting started.
perhaps use the asm examples and convert to swordfish?
will let you know of progress.
mean while ordering the switches and maybe the headers??

 

[Mikebits]

Considering cost and age, perhaps your goals are aiming to high, perhaps a demonstration to the whole group would be better, that is, you build it and they will come. You can be Mr.Wizard and maybe try to explain what is happening. If you have an oscope, kids like that sort of thing, hook up a mic to the scope, have the kids talk into the mic and they can see their voice, then maybe you can explain how the sound waves were converted to electrical signals.