I found a small violin lighter online. Since I have better things to do with my hard-earned money than give big wads of it to Faceless Multinational Corporations and the Government in return for a massively increased risk of an early death, I had an alternative use for it....
Having gutted the lighter mechanism and fuel resovior, and dremmiled off some of the internal supports, I used some double-sided foam tape to stick an Arduino Micro in the case, cutting out a slot in the bottom for the Mini-USB B-port.
I also double-sided-foam-taped an 8-ohm phone speaker on top. Grinding out a little slot in the opposing face of the 'violin' helped the sound get out better. The speaker is connected arross pins 2 and GND.
The little hole at the top where the flame used to come out was perfect for a salvaged push-button switch. The hole even had an aluminium support behind it to keep the switch in place! A 10k-ohm pull-down resistor between ground and Pin-3 and the switch between 5V and Pin-3 complete the circuit. This is a standard switch-sensor as per the Arduino Button Tutorial.
Then it is screwed snugly back together:
I adapted the arduino example Tone Melody, which also requires the pitches.h file as per the page just linked. I programmed it with the best version I could work out by-ear of "My Heart Bleeds for Thee."
And that's it! A nice quick one.
Sorry about the background noise!