Throwees are cool little LED lights that are made from a coin cell, an LED, a magnet, and some tape. The idea is to make a disposeable light that you can toss onto a steel object and have it stick. One by itself is not very impressive but a whole slew of them can make a rather dull object look interesting.
This instructable takes the throwee idea and puts it on steroids! I'll show you how to make a blinking throwee that will easily run for over a week.
Step 1: Bill of Materials
1) LED blinky light. Can be obtained free.. I'll explain a little later
2) lithium camera battery
3) rain proof container
4) basic geek items.. tape, soldering iron, wire, solder
First you'll need to get the blinky LED light device. You can buy one (un-resourceful of you) or, you can get tons of them for free! How to get them free? LED body lighting has become very popular in the night club scene. People buy them for $5 or so and eventually just leave them behind at the end of the night. A buddy at a nightclub, specially the cleaning staff can produce bags of these things!
The lithium battery. These are expensive but some ebay searching can produce really good deals. I bought as bag full of duracell 223 camera litiums for $5 plus shipping. These sell for about $7 or so each at the local drugstore. Ideally you want a battery like the 223 because its actually two 3v litiums in one package.
Rain proof container. Whatever you have on hand. I used a baby food jar since its what i could find. Plastic would be better for places were falling and breaking could be an issue.
Stuff you should have on hand if your an electronics geek.. thin stranded wire, solder, soldering iron, electrical tape.
Step 2: Electrical Assembly
First hack the battery apart! BE CAREFUL! Litiums get very angry when shorted and can explode. Be nice and patient!. If you look closely at the battery pack you'll see a seam. With patience and a cutting tool you can crack the seam and then pull it apart with needle nose pliers. Once the bottom of the pack is pulled off, use a non conductive object to push the cells out of the pack.
Once out you'll notice that the 223 pack is actually (2) cells wired together. Cut the strip that joins both batteries in half so you have something to solder to. You'll need to connect a positive lead and a negative lead to each battery. The strip that joined the batteries can be soldered to if you're a good solderer and dont overheat anything. Too much heat and the battery can explode. I'm very proficient at soldering so I soldered to the tabs on mine then lightly scored the top cap on the cells and quickly soldered leads on them. You may want to try another method such a modified battery holder if you feel queasy about soldering onto batteries!
Once the leads are in place you need to note the polarity and placement on the batteries that came with your LED light thingy. Once you figure out how its wired, pull the little batteries out and solder your leads from your big batteries to the circuit board on your LED thingy. Make sure you've got your polarity correct, do it wrong and you've burned up your throwee! The particular LED blinky I was using used two 3v litium calculator batteries. What we are doing is replacing the calculator batteries with something thats got much more capacity.
The new pack should make your LED throwee last for weeks if not a month or so! Tape up the pack so it cant short on anything.
Step 3: Pack It Up!
Step 4: Deploy!
I wanted to have fun with the drunks that sometimes wander down my street so I put my throwee in a tree on the easement. I used an automotive hose clamp that was pulled open to serve as a kind of hook and attached it to the throwee container with about 3 feet of cord. Toss the whole thing into a tree and it stays put.
Now it's just a matter of sit around and wait for the drunk to spot the UFO in the tree!