Intro: Simple Ultra Bright Flashlight
I recently bought a pack of 60° 1 watt led lenses from eBay and wanted to make a flashlight. Unlike some of my other projects, I wanted this one to have some aesthetic value as well as functionality. But of course, it still needed to work well. After going through several piles, bins, boxes, etc of junk I found that the lenses fit perfectly into a 3/4 inch copper pipe coupling. I designed the light around five different categories, five criteria if you will;
1: aesthetic appeal 2: brightness 3: durability 4: battery life 5: simplicity. with these in mind, I began searching through my junk piles once again for pieces.
Step 1: Category 1: Aesthetic Appeal
For me personally, there aren't many materials more attractive than shiny copper, it has such a beautiful gleam to it. As I said before, I found that the lenses fit into the copper pipe very neatly, making it the ideal building medium. The light is made of a length of pipe, a straight coupling, and a 45° coupling. These pieces were very dirty when I found them, so I used a bit of sandpaper, 220 and 600 grit, and steel wool, I think 0000, to clean and polish them. I was very pleased with the result.
Step 2: Category 2: Brightness
One of the most important aspects of a flashlight is obviously its brightness. If you've ever messed around with 1 watt LEDs you probably realized that they are very bright, but the light is so dispersed that its not very useful as a flashlight, maybe a lantern would be better. This is where the lens comes in, it focuses the light to a nice beam, perfect for a flashlight. Of course, the spot it's focused on becomes much brighter than before, again good for a flashlight. The LEDs I had are left over from another project of mine and are simply the led bulbs. Some LEDs come with the heatsink soldered on, mine did not, so the first step is to use some thermal paste and solder the led to the star base. Then I soldered two thin power wires to the led base. The lens simply snaps onto the led and then the whole thing presses nicely into the 45° coupling.
Step 3: Categories 3&5: Durability and Simplicity
I grouped these two together because they are so closely intertwined, as a general rule, the simpler something is, the harder it is to break. The copper piping actually serves two purposes, 1: it looks attractive and 2: it's tough. True, steel piping would be stronger, but I'm not really intending to throw it off a cliff, so copper is good enough. While thinking about how I could make the electronics as simple as possible, I came across one of those cheap aluminum flashlight, one of the ones that uses three AAA batteries. They use the aluminum case as one electrode and include the switch in the base, that's about as simple as it gets. I had another lucky break here, the switch from the aluminum flashlight fits almost perfectly in a 3/4 inch copper pipe coupling, exactly what I am using. So I simply pressed it in, with a little help from a hammer. The tight fit also ensures a good electrical connection between the switch and the copper piping. So, just like the aluminum flashlight, the metal case is used as one electrode. The other is a simple bolt stuck through a wooden plug. I used a wire-loop-thing (the things used to attach a wire to a bolt) and, you guessed it, used it to attach a wire to the bolt. See the pictures to get the idea. So there's one terminal to hook the LED to, but the other one is the copper pipe body. My first idea was to solder a wire to the inside of the pipe, but this proved impossible for my soldering iron. Instead I opted to wedge a wire between the wood plug and the copper pipe. I could then solder the leads from the led to this wire instead of directly to the pipe. The electronics are as simple as it gets, the led is wired straight to the wire-loop-thing and the wedged wire. This allows the led to connect directly to the battery, which means that it draws about 500 MA instead of the 350 MA it's supposed to. The power consumption is close to 2 watts, yes it is a 1 watt led, but it's OK. If you want to bring the power down to 1 watt, simply use a resistor in series with the led. I just soldered and heat-shrink-tubing-ed the led leads to the wire-loop-thing and the wedged wire, then pressed the 45° coupling on the end of the pipe, over the wooden plug.
Step 4: Category 4: Battery Life
A super bright, durable, attractive flashlight is great, unless the battery only last 4 seconds (OK a bit of an exaggeration, but you get the point). So battery life is also very important. As it turns out a lithium ion 18650 battery fits very nicely into a shotgun shell, which in turn fits perfectly into the 3/4 inch coper pipe. The coupling fits a 26650 battery very snugly, but an 18650 battery is a bit loose. So I cut a piece of a 26650 to 18650 adapter tube and stuck it in the coupling at the switch end. I also cut a shotgun shell (used of course, don't cut into a live round) and stuck it into the pipe body. Make sure to cut the pipe body to the correct length for holding the battery. To hold the battery in just press the coupling onto the end of the pipe, the pressure is enough to hold the battery in.
Step 5: Finishing Touches
The flashlight is now finished, or so I thought. After about a week of using it the copper developed an ugly tarnish that not only looked awful, but made anything that touched it smell horrible. So to fix this, I used sandpaper and steel wool to take e tarnish off, then I simply sprayed it with clear polyurethane. This prevents the copper from tarnishing. Instead of waiting a week and having to re-sand the entire thing, just give it a quick coat when it's built, let it dry for a day or two, and it's done. You now have a durable, bright flashlight with good battery life, and it looks great to boot! Best of all, it's easy to build and is super customizable, different combinations of pipe lengths and coupling styles leads to nearly infinite designs.
Comment below with suggestions, criticism, or if you made one.