Why over-complicate things ? Sometimes all you need is something simple. Paul over at DorkBotPDX decided his Monty Python theme costume needed a little extra flair, so he built a tiny sound clip player using some transistors, a teensy 3.0, a battery, and a speaker.
The circuit is pretty simple, a 9V battery gets regulated down to 5v to run the teensy. The teensy does some quick pwm changing on a single pin while parsing a specially crafted audio file. The pwm pin fires into a single transistor that then fires either a PNP or a NPN transistor at 9V which turns a small pwm signal into a big pwm signal. The signal runs through a small inductor and decoupling cap to an 8 ohm speaker.
He’s got a schematic, a teensy 3.0 sketch, and instructions on how he converted the audio clip into the right format over on his blog. Check it out.