This is mostly a re-purposing hack - modifying a finished product into something else. Some basic tools and soldering are all it takes.
I built this a about a year ago but all parts used are still available. Where I won't be able to show you actual construction I will go over how to accomplish each step.
Step 1: Parts
- an Altoids tin, of course. Full-sized.
- a "folding ipod speaker" like the one in the photo below. $0 - $15, depending on if and where you buy it.
These are available all over - buy the cheapest one or you may find one at a thrift store or even already own one. We use it for the amplifier board; the speakers are too big. Mine had a tea2025b amplifier chip - it's like a dual lm386 but rated for 2 x 1 watts into 4 ohms at 6v input. It doesn't matter so long as the board isn't much larger than mine (it's a tight fit in there).
I think you will be hard-pressed to breadboard something like this yourself and make is as small. If you can etch your own boards, then you could use one of the tiny surface-mount chips which do not need DC-blocking caps on the outputs. The DC-blocking caps take up the most room.
- a pair of miniature speakers, Electronic Goldmine G18251 (www.goldmine-elec.com). $1.00/ea at time of writing.
Mine were removed from an old Sun Microsystems thin client, but these are the exact same thing.
- A stereo mini-jack cord. $0
If you've owned a couple of mp3 players you probably have one you don't need. You could also use one from headphones, but the wires might be very thin gauge and hard to use.
- a 4 AA battery holder with switch, Jameco 216187 (www.jameco.com) $1.05 at time of writing.
The one thing I disliked about the folding speakers in their original form was the use of AAA batteries. They just don't last very long. Since we have no room left over in the Altoids tin for much of anything, I went with an external pack and glued it onto the back. Yeah it sorta violates the spirit of an Altoids hack, but it more than doubles the run time and it helps the whole thing stand upright without falling over. You can get this without the switch, but it's useful, as it is hard to mount the board in the tin so you can get to its power switch easily.