Putting thread to my previous post on adding a speaker for raspberry pi, I'd like to happily tell that now there is an on board speaker for raspberry pi, that will consume power from the GPIO power pins 5V and GND. A low power audio amplifier IC is used to make this possible. All you have to do as an extra effort is to use an adaptor that could supply at least 1.5A to the raspberry pi. Will post the schematic and photos soon...!!
Passionate electronics hobbyist.