I wish it were that simple but the people in charge of the school likely don't know what soldering is and if they do they may think of a propane torch being used to join pipes together.
The kind of work I do in schools is not always viewed as high priority so I don't necessarily get the same room each week if I get an allocated room at all.
I would like to teach the kid to solder but we'll see how the solderless kit goes first.
Old Guy
Yes if I can get such a room allocated.
Old Guy
Note that the solder supplied with that kit is lead-free, so with a CSA-marked soldering iron, there should be little room for panic. It's no more dangerous than a stove top.
Best regards, Spehro Pefhany
-- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
you
it should not be at all dangerous. Let the school know in advance, so the re are no complaints if the smoke detector goes off. Maybe they have a roo m that is better to use than some other rooms.
leted project.
opper roof flashing so she can make jewelry. Will probably have to use a p ropane torch.
tube super regen. receiver that year out of the " First Radio Book for Boys ".
r on one side wired to control a receptacle on the other side. That way yo u can keep the soldering iron warm and turn up the heat when actually sol dering. I have one and use it so the iron tips do not get dirty.
God help you if that kid burns her fingertip and child protective services finds out!
CSA-marked soldering iron, there should be little room for panic. It's no more dangerous than a stove top. "
If this is in the US, there is much danger. If a smoke detector goes off, m ost likely the fire department and the cops will come. When they find out, it is very likely that there will be an arrest. Guess who.
Sorry, but that's the way it is here. If take baking soda and vinegar, mix it in a jar an the lid pops off, as a STUDENT you can be chargd with a felo ny. This recently happened in Florida (IIRC) and the girl had to screw arou nd to get her record straghtened out, if it ever did get straightened out. As an adult he would be looking at jail time. The student actually used (II RC) Draino and aluminum foil, outside in the parking lot, and got arrested for a FELONY.
As such I would recommend agianst anything that gets hot or plugs into the wall. It's a sad state of affairs but this is what this country has become. A kid, like in the third grade will be expelled for just making the gun sh ape with his hand, or drawing a gun or perhaps even saying "boom". It's jus t how the indoctrination is here.
Now I actually didn't just come here to bitch...
I recommend a breadboard. I think they're still available and they can be u sed for a variety of projects. We could all just draw up some simple circui ts that use simple, disctrete components and do a variety of things.
For example, with two breadboards, in a few minutes we could draw up not on ly a radio receiver, but a transmitter. Why go for the useless commercial a irwaves ? Demonstrate the invention the Marconi no longer invented. (yup, t hey switched it and gave it to Tesla)There are a whole bunch of things that could be done and inspire.
As long as it all runs on batteries.
What's more with a standard breadboard, the door is open to future projects using old fashioned (read cheap) ICs, even digital ones.
One thing that I think would help at an early age is a scope. Show the kid the signals and explain the scope and what it displays. (that would be the ONE thing that plugs in if they allow it in, they might think it's a bomb o r something) The kid's own voice form a microphone and such, the (AM) modul ation on an RF carrier. The frequency matters not as long as the power is v ery low, unless the FCC SWAT team is nearby. Yes, the FCC has a SWAT team f or many years now. They busted a farmer a long time ago for rebroadcasting satellite (the OLD satellite) radio with an FM transmitter to his tractor s o he could listen to it as he plowed. They treated him like a meth cooker. (they also do that if they find out you are selling raw milk in many states )
Damn, thinking of the things we did in school when I was a kid, I probably still wouldn't be out of prison.
OK, I know it is in Canada, but they're kinda funny there as well. I think the paranoia is contagious...
On a sunny day (Sat, 18 Jan 2014 21:53:40 -0500) it happened "John Smith" wrote in :
You are right, even if the thing is just about connecting things together, then it _still_ will give the kid a feeling of what those parts are, antenna coil, tuning capacitor, LC, crystal earpiece.
Philips used to have kits like this with screw terminals that actually had transistors, was it not Philips pioneer? (pionier)
On a sunny day (Sat, 18 Jan 2014 21:17:09 -0800 (PST)) it happened snipped-for-privacy@gmail.com wrote in :
US is doomed, few more generation wrapped in cotton wool for safety and your enemies will kill you by fear by simply lighting a match!!
:-)
All over 4 you.
On a sunny day (Sat, 18 Jan 2014 19:44:42 -0500) it happened Spehro Pefhany wrote in :
Anything with the word 'gun' in it requires a sanity certificate for buying.
:-)
On a sunny day (Sat, 18 Jan 2014 18:27:20 -0500) it happened "John Smith" wrote in :
You could go zero IF, use flank detection, or pulse averaging
mixer
100MHz FM ->--- tr1 ---->---- few hundred kHz sweep - one shot of sorts - lowpass - audio -- | or: ^ 1 pole RC lowpass --> -- AM detector -->- audio | tr2 oscillator 100.1 MhzThere are many ways, even the simple tuned AM crystal radio will give audio on FM if detuned slightly as flank detector:
100MHz FM --->--- LC --->--- AM detector diode --->--- transistor audio amp -- earpiece. 100.05 MHzstation at 100 MHz | | . | . . . . . . . . . . . LC bandpass curve . freq. deviation AM output into simple diode detector, earpiece
There are many more ways....
Does this really work in practice or just produce disappointing results, which is bad for the student, loosing all interest in electronics ?
Assuming ordinary LC resonators, you would expect to get a Q of about
100, so the -3 dB bandwidth would be 1 MHz, so the -3 dB point would be 500 kHz from the tuned frequency. Putting the carrier at 600 kHz and with +/-75 kHz deviation, the band would be 525..675 kHz from resonance (that is much less than an octave), generating very little voltage in slope detection mode.Using a full size 75 cm, 1/4 wavelength resonator with Q of several thousand, tuned to 100.050 MHz would of course give a nice signal from a 100 MHz broadcast FM signal.
On a sunny day (Sun, 19 Jan 2014 13:16:48 +0200) it happened snipped-for-privacy@downunder.com wrote in :
Yes but now you have the 2 transistors as audio amp, 10.000x perhaps. Also tune a bit further away from the top where it is less flat.
Flank detection works.
If you want FM deviation SENSITIVITY, then mix down as in the first example, to say a few MHz, with a self oscillating mixer (first transistor), so now you have 2 LCs, and use flank detection at that LC, and the second transistor as audio amp.
100 MHz FM --->--- LC --->--- self oscillating mixer at 99 MHz --->--- LC at 1 MHz --->--- AM detector diode --->--- audio amp --->--- earpiece. 100MHz TR1 flank detector TR2There really are many many ways to do this with 2 transistors.
I think for the 'student' it is important the know about AM, FM, and detection methods, LC curves, Q, solutions that exist, and do experiments.
These days you can buy an FM radio for 3 dollars (ex battery) but in the chips used is a whole lot of art, really. I grew up with little crystal radios, and wound coils as a kid, listened secretly to radio at night in bed... I was not allowed to use a soldering iron, so I heated an old screwdriver in the coal fire, and used that as soldering iron. What I could not buy I would steal. Very young at that time. got books from the library, my mother had to get a special permission as I was considered too young to take those... Electronics my life.
This one should give good (linear) audio:
100 MHz FM --->--- LC --->--- self oscillating mixer at ~99.9 MHz --->--- one shot pulse generator --->--- audio lowpass --->--- earpiece. 100MHz TR1 TR2The one shot can just be a transistor with RC on the base and a capacitor collector to ground, ear[piece] will filter any RF. Needs a strong input signal though. A big antenna can give a lot (folded twin cable at 1/2 labda, dipole, would perhaps work, I once did a crystal TV receiver that way, miles away from the transmitter, 67.5 Mhz (ch 4 here), AM, negative modulation, 2 transistors to get up to CRT level, its all so easy, see scope_tv:
It is a pity there was not an earlier internet way to publish experiments, I would count for hundreds if not thousands.
F
That sounds tough. You might try educating the administrators. Bring in a soldering iron or gun and show them what soldering is. And try to explain that kids need to learn how to do things in school, because otherwise they learn on their own without any supervision.
Dan
Really good idea. Look at ebay item 400486059008 and then 350790837759
Dan
Yes I had one, can't remember a lot about it now but my Dad's brother's family had already used it and I don't think I got any of the projects to work because most of the transistors (Some BF194s and BC148s) were already blown. I did learn a lot from it though and I probably still have the manual somewhere. It had proper radio receivers (superhet). The kit I have ordered looks similar but has fewer parts
Old Guy
Yes. My still working Hameg HM203-4 is a bit big to take into a school so I've been thinking of replacing it with something of equal or better performance but tablet size. What would you recommend?
Old Guy
I don't think he'll lose all interest. We've already built an electric motor which worked fine.
Old Guy
Bringing anything that even *looks* like a gun, much less is actually called a gun, into a school will get you 20 years in the graybar hotel, if not worse. Hell, even a kid chewing his Poptart into the shape of a gun got him expelled for the year.
BTW, Sayal has some educational kits, and you can go look at the stuff in their showroom. I don't see a radio kit, though.
Best regards, Spehro Pefhany
-- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
What the h-e-double-hockeysticks happened to you guys?
Best regards, Spehro Pefhany
-- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
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