The hot chocolate speaker was surprisingly hard to design and build - it's all quite fiddly, but I think the end result is totally worth it. 

The panels on the outside hold the power socket, power switch, potentiometer (for volume) and audio jack. Everything else is fixed to the structure on the inside. 

I documented the build/test process here:

On the inside of the tin is a 3D printed structure which holds the speaker and circuit board.

On the outside are some panels which hold the controls - this is where you plug in power and your audio signal.

Something which is important to point out is that the bottom of the 3D printed structure is not a full circle - it has gaps either side which you see in the photo below. This means when it's pushed down inside the tin, it does not hit into the wires sticking out of the power/audio components mounted on the side of the tin.

There is no programming in this project, it's just built around a sparkfun Mono Audio Amplifier board which worked really well and was simple to work with. Would recommend!

Here's the circuit diagram. I did it on Powerpoint lol.

And finally, here's the CAD!

I'd be delighted if you checked out the video above, I'm trying to put effort into documenting my projects well.