Simple Demo Projects For 11-16 Year Old Newbies / General Science and Electronics / Forums

Forums

4hv.org :: Forums :: General Science and Electronics

« Previous topic | Next topic »

Simple Demo Projects For 11-16 Year Old Newbies

1 2 next

Move Thread

LAN_403

Dave Marshall

Fri Nov 05 2010, 12:34AM

Registered Member #16 Joined: Thu Feb 02 2006, 02:22PM
Location: New Wilmington, PA
Posts: 554

I'm a merit badge instructor for the local scout troops, and I'll be teaching a Radio merit badge class later this month. Included in the merit badge curriculum is some basic electronics theory. They learn how to read schematics, the basic functions of passive components, that sort of thing.

In the past, as a bit of an additional activity, I've had them breadboard a simple oscillator with a 555 that also serves to help them understand the concept of waveforms and frequency. I'm still going to build that, but I'd like to have them build something a bit more interactive, but still nice and simple. Bonus points if it's all analog, but some simple logic gates could be incorporated. Anyone have any good ideas?

-Dave

Coronafix

Fri Nov 05 2010, 01:39AM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

Can't go past a simple crystal radio! It's got it all, inductance, capacitance, resonance, impedance, rectification. They can even make a high impedance headphone.

ScotchTapeLord

Fri Nov 05 2010, 02:10AM

Registered Member #1875 Joined: Sun Dec 21 2008, 06:36PM
Location:
Posts: 635

You can feed the 555 timer signal into a small speaker and have them adjust the frequency to change the sound. Or maybe a simple microphone > op amp > speaker thing.

Or DRSSTC. :P

GhostNull

Fri Nov 05 2010, 03:56AM

Registered Member #2648 Joined: Sun Jan 24 2010, 12:45PM
Location: Australia
Posts: 291

How about a simple FM transmitter?
like the one here:

Adam Munich

Fri Nov 05 2010, 04:16AM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

How about a can of sound? It's a 555 timer circuit I designed when I was 13, and it varies the frequency of the sound it makes depending on light. Sadly it was lost due to my father being put on this earth solely to toss my favorite stuff out.

3 year old schematic >

Add a 50k pot in series with the CDS cell. It'll allow you to adjust for different lighting conditions. A power switch is OK too!

Put it in a slim-jim can and decorate! >

When you move your hand over the translucent top and cast as shadow, the sound gets lower. The darker the light the lower the sound. It's a great time waster and a really fun project to do, and it'll also teach them about frequency. Plus it's so cheap to make everyone could make their own for $3.

If you want I could make a new one tomorrow and post a video. Edit: I'm going to do that anyway.

Sulaiman

Fri Nov 05 2010, 07:38AM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3141

Since a crystal-radio is one part,
how about a simple audio amplifier?
Discrete would be good for learning,
an LM380 or LM386N-4 would be simpler and more impressive.

A two transistor astable with leds is popular,
and can be increased in frequency for a morse code 'buzzer'

Thomas W

Fri Nov 05 2010, 07:55AM

Registered Member #3324 Joined: Sun Oct 17 2010, 06:57PM
Location:
Posts: 1276

mabye a frequencey generator and put that through a speaker?

Barry

Fri Nov 05 2010, 02:51PM

Registered Member #90 Joined: Thu Feb 09 2006, 02:44PM
Location: Seattle, Washington
Posts: 301

A fun project is a bone conduction headphone to listen to a portable radio.

You can build a two-transistor current amplifier to drive a dc motor from a small portable radio. The motor drives a wooden stick or dowel that, when clamped in your teeth, lets you listen to music.

It's not very practical as a daily headset (your jaw gets tired) but it's very unusual and fun, and people like to explore what happens when you bite the stick in different ways. You can't imagine what it sounds like until you try it and music appears from out of nowhere in your head.

If you want a circuit design, let me know and I'll try to find my schematic and take photos of what we built for an 8th grade project several years ago. If there's much interest then I'll add some pages to my website.

Cheers, Barry

Hon1nbo

Fri Nov 05 2010, 03:14PM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042

Built a Theremin based off of a simple radio circuit with a suitable antenna - I know this can work at FM frequencies as the antennas on FM transmitters are easily coupled capacitively with the Human Body to adjust the performance, I'm sure it could be done in reverse with a little trickery for gain.

-Jimmy

radiotech

Fri Nov 05 2010, 05:16PM

Registered Member #2463 Joined: Wed Nov 11 2009, 03:49AM
Location:
Posts: 1546

Do the Scouts have a badge booklet? The last Radio Badge booklet
I saw had a few simple tube designs. If you have that, it sure would be more interesting (and tricky) that a whole Google-load of whats on the net now.

1 2 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob