Built a player and audio amplifier that plays a .wav file from an SD Card, based on this circuit / tutorial:
Build a Great Sounding Audio Amplifier (with Bass Boost) from the LM386
Sadly, despite what it says above, it doesn’t sound great.
So, need to investigate some better options for sound output for this, clearly.
In the meantime, am going to investigate the tilt switch aspect of this build – http://www.amazingtips247.co.uk/2017/01/tilt-switch-arduino-with-sound.html
As well as how to then make this work randomly:
http://forum.arduino.cc/index.php?topic=295411.0
And using other (proximity) sensors:
https://create.arduino.cc/projecthub/javier-munoz-saez/arduino-mp3-player-distance-sensor-fun-6b1bce