Step 1: "Make an LED flashlight out of ..."
"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!
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
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
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
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
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.
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
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!