Introduction: 6 Million Rupee LED Flashlight Out of a Lithium Battery!

This pocketsized flashlight packs more amphours per ounce into your pocket than anything you could buy... if you dare to make one.

Step 1: "Make an LED Flashlight Out of ..."

You've seen them. They propagate like syphilis. They are Unoriginal LED Flashlight Instructables.

"Make an LED flashlight out of ...":
an Altoids container!
a Tic Tac container!
a Mini Altoids container!
an empty 9 volt battery container!
an Altoids gum container!
an empty film canister!
a used wad of toilet paper!

Well, this one is DIFFERENT. It's difficult, dangerous, and just plain time-consuming. So don't try this at home, unless your middle name is Danger. And you first name is Nerd. So, you're still interested? Ok, then. Step into the light.

Step 2: Lithium!

If you have played with lithium batteries before, then you probably know the deal. Lithium batteries have awesome ability to store energy for long periods of time. They hold a massive amount of charge. They can be recharged like no one's business. But they are also dangerous. Excellent. They can also be found for free. Even more excellent.
For the free-ist lithium batteries, try asking at the local electronics store where they have recycling bins. Sometimes the guys are ok with you taking home some "dead" laptop batteries.

What do you want with a "dead" laptop batttery? Well, don't get me started on the subject of laptop batteries, else I'll wind up in Guantanemo Bay. Let's just say that it behooves certain people to make you think your laptop battery is dead when it really isn't. Of the laptop batteries that I have taken in, only 1 in 5 is truly anywhere near dead.

Step 3: LED's

So, I have a lithium battery. Now I need some LED's. Darn. I just sold off my LED collection to pay my light bill, and this contest just appears out of nowhere. I appropriated the LEDs from this 3 million rupee flashlight I made two years ago.

With the help of a propane torch-heated exacto knife, removing the LEDs wasn't too hard. It used up a lot of elbow grease, for sure. But in my Mountain Dew fuelled modding frenzy, I couldn't stop to buy some new ones.

Step 4: Making the Light Assembly

One of the LED's didn't survive the surgery. I saved it, anyway, to be used as a spacer.

With some sandpaper, I removed the rims from the LED's so they could be packed together closely, in a honeycomb pattern. I put the dead LED in the center.

I used hotmelt glue to tack each LED onto the center LED. On each LED, I oriented the cathode towards the center. Once assembled, I wrapped some packing tape for temporary suppport.

Step 5: Soldering

So, now take a look at the pics for some improvised contruction techniques - safety of which is unknown. I can't seem to make pic notes, so I'll describe:

1. solder the cathodes together and solder a wire
2. dab with hotmelt and cover with teflon tape or some other insulator that won't melt. Heavy craft paper or index card would work
3. put a dot of copper foil tape in the center
4. solder a 15 ohm resistor to each anode, and join them all on your center copper tape pad.
5. Solder a wire to the center pad.
6. Now you have two wires. One for the common cathodes, and one for the anodes. The LED's are all in parallel, with a 15 ohm resistor on each one.

Step 6: Battery

Now back to the battery. We'll add a recharge port, first. Then we'll solder the circuit together. I used a pic and a mosfet to control the power, the only reason being I could use a smaller switch. Talk about Rube-Goldberg. I didn't even put in any fancy flashing patterns or dimming features. It turns on, and it goes to sleep. See pics for details.

1. After insulating the rim of negative terminal at the top, I carefully cut out the protruding bulk of the positive terminal. Why? to save a millimeter or so of length. Yeah, that's probably not worth the risk.
2. I carefully filled in the depression with hotmelt glue, then I carefully soldered a female SIP header pin and wire to the remnants of the positive terminal.
3. I carefully slipped the rest of the header over the soldered pin, then soldered the outer two pins down to the rim of the negative terminal.

Notice how many times I used the word "carefully." If you short the battery terminals, the battery could instantly heat up to the temperature of thermite, fusing the battery to your skin only to explode in your face just a few milliseconds later, causing permanent blindness! Or you might see a small spark, hear a small click, the safety valve may or may not pop followed by a dribble of clear fluid, indicating that you have just killed your battery.

Step 7: Circuit and Putting It Together.

Because I programmed a PIC, I did not make a schematic. But I'll show you a picture, anyway. The big chip is the PIC. It's a DIP part, but it's sanded down so it's wafer thin. The smaller chip is an SOIC n channel mosfet. I soldered everything that is grounded or NC directly to the battery. The button is also soldered to the battery. Well, half of it is. The other half is insulated with teflon tape.

pic2: I used a dab of hotmelt glue to adhere the LED assmebly, then carefully soldered the wires.


pic3: Typically, on a project like this, I'm shooting for a 50-50 chance of success. I'm kinda winging it. I'm not sure how many watts the resistors can handle. The mosfet isn't a logic level device. So on, and so on. Well, I pressed the button, and woot. Works perfectly.

Step 8: Finishing

The light fixture and recharge port need to be epoxied for structural support. The smd resistors are especially prone to cracking. Even more importantly, all exposed parts of the positive terminal and any wire/lead/pin connected to it must be protected from accidental short circuit. So I didn't leave this one all up to hotmelt glue.

I used this stuff. It's called Kneadatite. It's like modelling clay, but it's really epoxy that sets in about 12 hours, or so.

Hope you enjoyed my latest adventure in electronics.

See ya next time!

Comments

author
joeofloath (author)2009-11-13

You don't know a short circuit until you short a 7.2v, 4.5ah ni-mh RC car back, The wires glow red hot, and the cells go off one by one like shotgun cells.

author
tutdude98 (author)joeofloath2013-09-01

nimh can give about 8 amps in short circuit max but car battery can give 20-100 amps so if you short car battery it will be about 1200 W in short circuit and with nimhs you will get about 58 W :D

author
joeofloath (author)tutdude982013-09-01

It's not that simple I'm afraid, it depends on the C rating of the cells and how big they are. A 300mAh nimh from a wind up torch will give maybe 150mAh, but a massive cell the size of your head (like they used in the GM EV1) could pump out hundreds of amps.

author
tutdude98 (author)joeofloath2013-09-01

i have AA 1.2v 2,1A nimhs and in short circuit they can give 8 amps like most of new nimhs so they can give 4C for 2-3s

author
joeofloath (author)joeofloath2009-11-13

Or a car battery. But I've never done that. Well, apart from that one time with the 5 inch electric motor...

Lwts just say sparks flew, and rather thick metal glowed.

author
sokamiwohali (author)2012-09-08

how do you re-charge it?

author
or_ford98 (author)2012-01-19

6 000 000 Pakistan rupees = 64,030.3671 Australian dollars

author
or_ford98 (author)2012-01-19

6 000 000 Indian rupees = 114,678.07 Australian dollars
its alot bro

author
ElectroFrank (author)2011-03-17

You programmed a PIC ? I don't want to sound like a wet blanket, but .... isn't it (a lot) cheaper to buy a flashlight than a microcontroller ?

author
klee27x (author)ElectroFrank2011-03-21

The whole point was to make something that I cannot buy, and to reuse some "dead" laptop cells. I still use this flashlight, today, with no mods or repairs.

BTW, microcontrollers probably cost less that you think. This one cost me about 60 cents.

author
ElectroFrank (author)klee27x2011-03-21

Fair enough, I'm obviously not keeping up with prices going down ! And I guess the practice of programming is always good. BTW, can you recommend any sites where I can pic up PIC programming ?
(I have a good basic training in microprocessors, it would be nice to find a teaching community and coding tips. As the PIC and PICAXE system is well supported as an educational tool, it seems like a good one to get one's teeth into.)

author
klee27x (author)ElectroFrank2011-04-20

There are a lot of online tutorials that will get your feet wet. But the most imortant stuff is in the datasheet. I suggest you print out the entire datasheet (all 200-450 pages) and bind it into a book. There is a lot of info in there you'll need to refer to frequently, unless you have a photographic memory.

Microchip has fairly active forums if you have specific questions. But to formulate a specific question, you'll have to read the datasheet. :)

As far as learning assembly coding tricks, Micochip has dev boards and tutorials for various devices. If you can follow the schematics and/or make your own boards, you can then download the turorials for free. They'll cover some basic programming tricks, such as making delays, using interrupts, how to make macros and subroutines, etc.

author
elinventor21 (author)2010-07-16

how do you program the thing?

author
klee27x (author)elinventor212011-03-21

That's a bit more complex. I suggest you look up some microcontroller tutorials if you are interested in that.

author
konger (author)2010-07-25

What 'bout the PIC program and the circuit diagram?

author
maxpower49 (author)2009-02-27

what if my first name is danger and my middlie name is nerd

author
klee27x (author)maxpower492009-03-02

Then I'd like to meet your parents.

author

Their names are Toil an Trouble.

author

and the father's name is bubble. so now they're bubble and bubble. first names toil and trouble.

her maiden name was schmidt. quite unoriginal.

author
roberto sirigu (author)2010-01-17

me gusta......
Mejor con in poco de funda termoretractil

author
nerd12 (author)2010-01-11

are you indian?
what does the title mean?

author
D5quar3 (author)2009-12-25

 what's the point of a PIC do I really need it

author
klee27x (author)D5quar32010-01-04

As I explained, it's only there so I could use a super kewl tiny push button to toggle the flashlight on/off. You could just use a switch, but that would only be kewl. Not super kewl.

author
RANDOMFISHYFACE (author)2010-01-03

 just plain awesome but too dangerous for me

author
northernmagnet (author)2009-12-24

 could i use a button battery? (3v x 3) 

author
klee27x (author)northernmagnet2009-12-25

Dunno why you would want to spend that much time on a small disposable battery, but yeah. It would be litte more than a throwie, though. :)

author
Redgerr (author)2009-07-15

""Make an LED flashlight out of ...": an Altoids container! a Tic Tac container! a Mini Altoids container! an empty 9 volt battery container! an Altoids gum container! an empty film canister! a used wad of toilet paper!" AHAHAHAHAHAHAHAHA YESSS -- other than that.. amazing cheif, i really like this and i have a TON of 'dead' laptop batteries around my house (just disasembled 2 laptops and 3 desktops LOL) and id love to try this!! Thanks!

author
luketanti (author)2009-06-02

Hello. I have a bunch of these batteries and i need to know : Can I charge 3 cells in series which makes 11.1volts with a 12.6 volt LM317 charger without any protection circuit? I'm going to use them to power a portable amplifier. The battery model is CGR18650hm Panasonic.

author
klee27x (author)luketanti2009-06-02

Well, it could be done, but you'd have to find out yourself what the max current is. A TO-220 lm317 can sustain >2A output if it's properly heatsinked with a fan. So you'd be relying on a nonheatsinked part, possibly of a smaller package (like a Dpak) to limit current to under an amp or so, and it would get very hot. I'm not sure how long a 317 would last if used like this. It's kinda a hack method, and I don't really recommend it to anyone.

It's far better to use a variable output supply and an ammeter, or to use some active current limiting.. or even passive current limiting. A 5 ohm 5 watt resistor in series with the battery would pretty much ensure a safe current limit for a 3 cell battery charged at a fixed 12.6V. But it would also increase the total charge time by quite a bit.

author
Dirk5 (author)2008-06-10

have u herd of mega capacitors they stor like 300 farads once i get my hands on i'll make one with one of those

author
klee27x (author)Dirk52008-06-10

I thought they were called "super" capacitors. Yeah, those are pretty neat. Add a high efficienty DC-DC converter, too, while you're at it!

author
Dirk5 (author)klee27x2008-06-23

actually i hate to correct you but there is something called mega capacitors but there super new and hard to find

author
lasermaster3531 (author)Dirk52008-08-23

also ultra capacitors

author

Also super duper ultra mega capacitors.

author
ReCreate (author)JamesRPatrick2009-01-29

also super'duperpooper'scopper capacitors

author
lasermaster3531 (author)ReCreate2009-02-02

what is a scopper?

author
ReCreate (author)lasermaster35312009-02-02

it just goes in with everything else

author
Chiefhalo19 (author)ReCreate2009-02-19

i really hope all you guys know that capacitors only hold their charge for less than a second, in other words, once you discharge it, all the energy leaves at one time, not like a battery.

author
Mark620 (author)Chiefhalo192009-05-27

not so...it depends on how you discharge it.

author
lasermaster3531 (author)Mark6202009-05-31

seriously. if you have a 5- or more farad supercap it will run a low power led for at least 10 minutes. however, if you short it with some wire it will run out in less than a second.

author
rocketman221 (author)Chiefhalo192009-02-24

i made an led keychain light with a pair of .5F 5.5v super caps and it runs for 15 minutes. but it does self discharge after a few days though.

author

add a solar panel to charge it with sunlight. maybe make it a pull-out compartment so the panel doesn't break. see if you can find one of those flexible solar panels that will roll up ti fit inside it. new tech. awesome.

author

iv got a 6v 5mA solar panel but its a lot bigger than the light.

author

you will need a solar panel that puts out less volts and more milliamps. i have heard of a flexible solar panel that could roll up to fit inside it. less efficient than a silicon panel but much cooler.

author
ReCreate (author)Chiefhalo192009-02-19

ah-duh(like ah-choo!) some caps hold they're electricity for a few minutes,a coin-size shaped capacitor,you charge it for some 3 minutes and it lights up the led for a few minutes like a horrifically bad rechargeable battery

author
lasermaster3531 (author)ReCreate2009-02-20

it depends entirely on what it is powering. a 60 megaohm resistor will take a long time to discharge a camera cap, and they are only 120 microfarads. a 3.1 volt 5 farad capacitor can run an led for like 10 minutes. it all depends on how much power it uses.

author
ReCreate (author)lasermaster35312009-02-20

so,the higher the farads the longer it will last?

author
lasermaster3531 (author)ReCreate2009-02-23

yes. and the less power the device that it is powering uses, also a 500 farad cap that is 5 volts won't work on a 5 volt circuit. as it discharges, the voltage plummets in an exponential curve. a five volt cap will run a 1 volt circuit a lot longer than a 5 volt circuit. use a power circuit to take the 5 volts down to a steady 1. i have seen a circuit that uses a 10 farad 4.1 volt supercap and a pulse circuit to make 9 volts to mimic a nine volt battery. you could do the same thing for an led flashlight. hope this isn't too confusing!

author
ReCreate (author)lasermaster35312009-02-23

i understand it... i think im not a dope so i get it :wink: <_- ah there is got it! a wink <_-

author
lasermaster3531 (author)ReCreate2009-02-24

yup.