So what is a “Heat Shrink“?    Its a popular tool we use in the hobby electronics industry.    It is actually is a tube which shrinks in diameter when heated.

Purpose: Heat shrink is used to insulate wires offering abrasion resistance and environmental protection for conductors, connections, joints and terminals in electrical engineering. It can also be used to repair wires or bundle them together, to protect wires or small parts from minor abrasion, and to create cable entry seals, offering environmental sealing protection between bulkheads and adding sealability to electrical junction boxes.  - Wikipedia

I guess that says it all.   For me personally,  I use it to cover solder joints.  Usually when I’m extending a wire, I cut a small piece of heat shrink tube, about 2 inches in length or enough to cover the exposed wire splice.    I then put the heat shrink tube first and then splice the wires and start soldering.

Once the wires are soldered,  I moved the heat shrink tube in position to cover the spliced part and then fire up my hot air blower (I have a hot air soldering station),  but your average hair dryer will do.   Sometimes I just use my soldering iron and quickly move it across the length of the Heat Shrink tube.

This one is awesome. The author has an excellect documentation on how *SHE* did it from conceptualizing, to design, to prototype creation, then to kit production. She even discussed computations on efficiency of the charger. You can even follow her thought process on how she choose the parts to be used, and even details costings.

The resulting USB charger uses an altoids tin casing and it can charge mp3 player, ipod, pda, any device that can power from a USB port.
For all DIY people, you gotta see this.

[via instructables ]