Saturday, August 12, 2006

Tales from the 99¢ store

As you may or may not know, I like 99¢ stores and the garbage they sell. A new one opened up in my neighborhood, but I hadn't visited it until yesterday. It was much larger than any other such store I have been in and they had some stuff I had never seen before. They even had sun glasses, of which I bought two pairs (I should chronicle the saga of my sunglasses on this blog some day). I also bought one of those dynamo flashlights that you just shake up and it charges and lights up. After I brought it home, I realized that it was (almost) completely fake. It does light up (I tested this in the store even though a handwritten sign said not to), but it is powered by a pair of CR2032 lithium batteries. The dynamo is just for show, and the box just lies.

(click photos to make them larger):



Here is the box, note the lack of knowledge of the English language and the use of the word "torch", which is what they call a flashlight outside the U.S.



Its surprisingly bright for a fake dynamo flashlight. I believe this is due to the use of a pair of 3 volt lithium batteries, which may be too powerful for the LED (there is no resistor or anything), but then again, what do I know about electronics?



The top screws off and the plastic "lens" comes out. The guts also slide out easily. There is no parabolic reflector, just a flat foil thing behind the LED. Here you can also see the two batteries. The printed circuit board has nothing but the LED on it. Don't dynamo powered devices need a capacitor to store energy, and isn't it some kind of rule that you have to use resistors with LEDs?



Yup, its just a simple circuit of batteries, wires, an LED and a piece of metal as the switch.



Here, on the left, you can see part of the fake dynamo. That coil isn't connected to anything and the little "magnetic" lump has as much magnetism as, well, something not very attractive at all.



Here you can see the switch, and the lack of many of the components that would make a real dynamo flashlight work.



Here is that little lump that's supposed to be a powerful and dangerous magnet. I wonder if its poisonous...



And here are the lithium batteries that you aren't supposed to need. Luckily, this abomination of dynamo powered illumination only set me back 99¢.

23 Comments:

Anonymous Mark Healey said...

It looks like the parts are worth more than the 99 cents you paid. Is the coil good? About how many windings?

12:08 AM  
Blogger Matthew Siegler said...

And I too have one of these scandalous deceits! My quest led me to a discussion about them and an advertisement (now missing) from a Chinese export company. Here it is via google cache:
two type(reality one and fake one) of shake flashlight

12:12 AM  
Anonymous Anonymous said...

This is definately a crappy flashlight, but the current limiting resistor is NOT needed because the high internal resistance of the CR2032 batteries limits the current. As long as the current is within the specs of the LED, then everything is fine.

12:19 AM  
Anonymous Anonymous said...

those CR2032's are worth more than the flashlight. I'm hoping the dollar stores around here will have those specific (or simular) fake flashlights. Radioshack/meijer/any other store that sells just the 2 packs, has them for about $3-5.

3:29 AM  
Anonymous Sab said...

Perhaps, forgive me for saying, but perhaps... it may use the coil and the lump (AKA magnet) to charge the batteries so that you do not have to shake while trying to point the flashlight (AKA torch) at something.

4:08 AM  
Anonymous Anonymous said...

sab,
you really have no idea about electronics at all do you?

5:19 AM  
Anonymous Anonymous said...

Anon,

Perhaps it is you that doesn't know much about electronics.

Despite common believes, it is possible to charge most "disposable" batteries (alkaline, lithium), it just takes a long time as there are detrimental effects when you pass a lot of current through them.

However, by the sounds of things, the coil and magnet couldn't produce much of a current, so the batteries are safe, and they would charge slowly.

For low drain applications such as LED lighting, I think it would work OK, even if it does take a fair amount of shaking to charge the lithiums.

5:36 AM  
Anonymous Anonymous said...

This would work perfectly, provided the electronics needed to rectify and smooth the current from the coil were present, which they aren't, and that the coil was actually connected to anything, which it isn't. Read a little more carefully before asserting dominance.

6:13 AM  
Blogger Bill said...

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7:22 AM  
Blogger Daniel Rutter said...

It is exactly as easy to charge primary cells as it is to turn urine back into beer.

Yes, "alkaline chargers" exist, and there are even special "rechargeable alkaline" batteries to use with them, though they're a pretty darn boring technology.

Recharging normal primary cells, like regular alkalines and the lithium cells in this flashlight (well, assuming that they're real lithium cells :-), is not possible. You shouldn't try to recharge lithium cells, either, since they're very happy to catch fire if monkeyed with. A shake-light arrangement can't generate enough power to hurt them, though.

You can blow some current through some non-rechargeable batteries to burn off metal dendrites and kick the remaining reagents into reacting a bit more completely. That's what alkaline "chargers" do to normal batteries. This isn't worthless, but it doesn't achieve much and is not actually "charging". It's better to think of it as "stirring".

9:17 AM  
Anonymous Anonymous said...

Even supposing the cells were rechargeable without extra circuitry, and the coil was hooked up, it still wouldn't work. Simply because the "magnet" is just as fake as everything else! :)

10:54 AM  
Anonymous Anonymous said...

You know, I just somehow knew there would have to be a comment from Daniel Rutter on this. Did you actually hear the flashlight calling to you? :-)

11:24 AM  
Anonymous Dan Lockton said...

Interesting. It reminds me of the "fake solar cell" calculators that now seem to be flooding every 99p store in the UK...

e.g. see http://www.flickr.com/photos/danlockton/tags/solar/ for photos

P.S. I worked for a while with Daka, the company which designed the original 'Faraday Star' shake-torch... they seem to have a problem with fake knock-offs of a lot of their products.

12:30 PM  
Blogger vroemer said...

Most of them are fake I found on ebay somebody selling some that do work but instead of batteries it uses capacitors

7:30 PM  
Blogger Richard said...

I have one as well. I was disappointed when I realized that it used batteries. On the other hand, what do I care, it was cheap and has a nice magnet in it (my son managed to magnetize the TV's picture tube - requiring me to degauss it).

These sort of things abound. My most disappointing was a solar powered calculator I bought (several actually), because I wanted the cheap solar cells. sigh. They were fake - a slip of printed paper under a plastic cover..

5:39 PM  
Anonymous David said...

I've a flashlight very similar to this one. Same packaging also. I've spotted the 2 batteries previsously so I was thinking it's a fake too.

BUT : the flashlight works if i shake it and remove the batteries. It last like 2-3 minutes (don't know how as i can't see any capacitor). The led if far dimemr also.

Also, my batteries are not standard cr2032. They are the same size but can be recharged (i remember that it was difficult to find the battery reference number in google, it was not cr2032, i've just got a few hits leading to a chinese company saying the batteries are chargeable.)

However, if your coil is not connected, then clearly it's a fake.

10:28 AM  
Anonymous Anonymous said...

here's a puzzle - i have a fake Faraday light. i took it apart. the slug is not magnetic (appears to be aluminum). there are batteries, not a capacitor. HOWEVER, when i move the slug back and forth very near the outside of the coil, i can feel magnetic forces. i repeat, the slug is not magnetic. ALSO, when i move a non magnetic piece of steel back and forth near the outside of the coil, i STILL feel magnetic forces.
i think maybe there is a real magnet within the coil to fool people testing the apparatus from the outside.
seems weird that they would go to so much trouble . . .

10:08 PM  
Anonymous Anonymous said...

i am the poster (just before this) who thought the slug in my fake faraday light was aluminum. i wasn't thinking of its obvious heavy weight for its size, so i think it is lead or bismuth (hopefully bismuth, for the sake of the enviornment).
hmmmmmm . . . .

8:36 PM  
Anonymous Anonymous said...

i don't think this slug is pure bismuth, because it is attracted to a magnet.
bismuth is diamagnetic, but i don't think that would help these fake faradays.
it conducts electricity pretty well. it doesn't show signs of oxidation as would lead. maybe it is an alloy.
i wonder . . .

10:15 PM  
Anonymous Anonymous said...

Superbrite (white/blue) LED's use more volts than the regular red/green/amber variety, so a resistor isn't necessary until you get over 6V. source - http://www.kpsec.freeuk.com/components/led.htm

6:48 AM  
Anonymous Anonymous said...

I just bought a 100 of this sucks ass

4:24 PM  
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7:47 PM  
Anonymous Anonymous said...

Actually, lithium coin cells have a very high internal resistance. That is why you can get away with out the resistor (and also why they have such a very long shelf life). To a previous comment, I have to admit that I buy "junk" sometimes because the batteries are worth more than the asking price!

10:31 PM  

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