Picture of Make cool gadgets from a deceased fluorescent lamp
Do you have some deceased fluorescent lamps? If Yes, then you might still recycle some of its guts to fashion some simple yet usable circuits.
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Step 1: Car to portable MP3 player power supply

Picture of Car to portable MP3 player power supply
The first gadget is a 12 V to 1.8 V power supply, also known as step down or buck dc-dc converter. These type of SMPS (Switched Mode Power Supply) are very efficient in terms of energy loss by heat dissipation compared to the linear type (circuits like 7805, 7509, LM317, etc). This works under the principle of energy storage in a magnetic field and then just regulating the output voltage by means of duty cycle control on a PWM (Pulse Width Modulation).

Open up your lamp and look for a small ferrite core transformer (some brands might have two, so try different brands or sizes)

Step 2: MP3 PSU:Stuff you'll need

Picture of MP3 PSU:Stuff you'll need
Here is what you'll need:

-NE 555 (Timmer- oscillator IC)
-two 1N4001 or 1N4148 diodes or any similar (for low frequency)
-10k trimpot or potencimeter
-100n ceramic or polyester capacitor
-10n ceramic or polyester capacitor
-1000u X 25 V polarized capacitor
-Any N-Channel enhanced mode Mosfet for 5 A or greater current
-470 Ohm resistor
-A Schotsky diode (This is the most important item, since is should be a diode that can switch at high frequencies, thus the "fast recovery" tag) I got this from a deceased laptop power adaptor. They are very common.
-FROM YOUR LAMP, remove the xtransformed and if it is is still in goog shape, use it. If not, you can still use the core and rewind some 200 turns of magnet wire (30 or 32 AWG). Inductance of this coil should be in the mH range.
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hd1966 years ago
This site has spms step down regulators schematics with only 2 transistors:

very interesting
Looking over the diagram, if the output voltage is above the zener voltage minus the base-emitter drop of Q2, Q2 is shut off, denying base current for PNP Q1, turning off the feed from the input voltage.
Replacing a BC327 PNP transistor with a BD135 NPN transistor would be expected to not work.
unknownpocketnerd (author)  hd1966 years ago
Yes, they are great. Just 2 transistors and it is self oscillating.
bobhill1256 years ago
u could of died from the murcury in the bulb ur luky u didnt
There is nowhere close to a lethal amount of mercury in a cfl.
True. People are just trying to scare others. Or are stupid. If people looked at the different levels of mercury in different objects, a CAN OF TUNA, will give you more mercury than a broken CFL. Assuming you don't eat the CFL, just exposed.
Boy, I don't know - my neighborhood, myself, and all plant life within a 10 mile radius of my house died last week b/c one of my careless neighbors dropped one of these CFL bulbs and exposed us to the mercury.

This was exactly the way "they" say it will happen!

!?!?!lol you died! :) xD
sorry to say but mercury is not really the biggest threat to your health yes You really shouldn't mess around with it or break cfl bulbs or tubes. But mercury wont kill you. Oral thermometers all used to have it and most people (that I know)40 and older have broken mercury thermometers, even in their mouths ( accidently ). And they do not have any symptoms of mercury poisoning at all.
rcisneros4 years ago
Thanks for the tip. I never thought of looking inside a cfl for a toroid ring
can you put in a "real" schematic insted of this hand drawn one?
Sorry, I used a DOS version of ORCAD then printed them and scanned them. My old matrix printer is mechanically damaged. Freeware for electronic design are very limited in their libraries of symbols. Do you have a link to a good piece of freeware that has a good bunch of symbols?
I think your schematics are great. It's a pain to draw them by hand and you did a nice job.

I've tried TinyCAD, which is free and easy to use for schematics.
unknownpocketnerd (author)  cyberpageman5 years ago
Thanks. By the way, I have all of Forrest Mims' Engineer's Mini-Notebooks, by Radio Shack. Forrest drew them all by hand, no typing, no CAD, just good old fashioned schematics. I think this series was his Masterpiece. So I try, in my own way, to emulate him. I don't like to use computers for everyting, except for programing, but computer drafting seems a bit constrining.
Yes, your drawings are very similar to Forrest Mim's sensible schematics. I have many of his notebooks and value them.
Great guy still living in TX with his family, Did you know he corrected NASA and a temperature calculation used in global warming with electronics he built on his farm? The joke at the nearest radio shack when parts are missing like LEDs is that the last guy in the store was him! I keep missing him lol
Thanks for the clue. Because of what you said, I looked him up on the Internet. He has a couple of websites, and (which sells his books), as well as several science sites. Amazing guy.
I had a look at dai, which I personally use for UML drawings. It seems to have all of the symbols which you need, and I find a pretty usable program.

I have access to Illustrator through work, and i do a lot of technical drawings: Scientific figures, documentation for code and applications. In the situations where it is applicable (UML diagrams, electric circuits) it's my first choice application. It's simple and provides just the important features. This makes it quite efficient and easy to use for the kind of stuff I need to do.

It's a really old school drawing program, orginally implemented under X-Windows, but it's recently been ported to Gnome. There is apparently a windows version:
It is of course GPL'd.
whoops, I should have proofread more closely. In the second paragraph, my intent was to say that DIA is my first choice application, rather than illustrator. I only whip out illustrator when I have to something kinda fancy.
I use a software called ExpressSHC which has a bunch. it has all the symbols that you have on your schematic plus more. look it up on google. the download takes like 10 minutes but its free and works great. also, if your a really big electronic geek like me, the program automatically downloades a program called ExpressPCB. you link your schematic to it, send it to the site, and they send you a printed circuit board for it.....for a price of course. I used it to make a bunch of tv remote jammers (KipKay) and it's a lot easier to use than veroboard.
mr smart4 years ago
is there a way to make this into a dc to dc high voltage transformer ?
unknownpocketnerd (author)  mr smart4 years ago
Well, you'll need to do some calculations to guess the winding ratio. Or you can make a boost converter.
zippoge5 years ago
i think you forget pin 6, it must be connected with pin 2 
unknownpocketnerd (author)  zippoge5 years ago
you're right!  Sorry for that inconvenience.  Folks, please acknowledge this tip:  Pins 2 and 6 are wired together.
no ofense but you need to be a little more explanatory cause most of the stuff i didnt understand
Redgerr5 years ago
gona take some appart, dont wanna get any mercury in me though, gotta watch out
Be careful, those compact fluorescent bulbs contain mercury. Did you know that Incandescent bulbs will be banned in Ireland starting March 1st?
don't think it ever went into effect, I was at tesco the other day looking for light bulbs and I think I saw Incandescent bulbs.
They are also banned in UK, and many people are going crazy about getting the last bulbs from the stores...
I think their goal is to be environmentally friendly, but I don't think most people properly dispose of them. Also have you ever read the instructions on what to do if one breaks? It's ridiculous.
No, I have not seen the instructions, can you post me a link?

Whatever their plan is, the ban of the light bulbs turns out to be disastrous for many people.
I don't know where they are, but I think they're on the light bulb package. I'll look for instructions now..... Found them.
Damn, that is really crazy, you even have to pay a lot of money to get rid of them! I just simply take them apart. :-)
I heard that somewhere, maybe on the news or somethin. Also, your right you have to be really careful with these bulbs because they do contain mercury
Lord Kanti5 years ago
which component(s) contain mercury and how plausible is it to extract these components without exposure to the harmful vapors?
imakethings6 years ago
is this a CFL bulb? will i get the toroidal transformer even in 5 watt CFL?
110100101106 years ago
how do you protect the mp3 from getting 12 V if the pwm fails and the fet stucks in the position when current can pass ? wow for the instructable !
unknownpocketnerd (author)  110100101106 years ago
In my design, a 1.2 V NiCd AAA recharable battery is allways attached to the Buck Converter's output stage. Therefore the converter is allways loaded since power up. A zener diode will not hurt, though!
if you connect a 1.2 V zener to 12 V supply the zener will just fuse and go open circuit leaving the 12 V as is the 1.2 V battery and a fast fuse are good the fuse will blow before the battery blasts / leaks due to the high current the mp3 can still get enough of a shock of high voltage. a 1 - 5 ohm resistor in flameproof package in series with the supply lowers this shock the resistor itself may blast and go white hot for a split second if it happens (untill the fuse or the resistor itself burn out) hence the flame proof package requirement (some compact fluorescet lamps smoke / go off their base when they burn out due to such resistor. but 110 - 240 V are usually enough to fuse it so fast that it does not do much damage)
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