Gemma and Dan,
found that there are speakers that exist that are tiny and work in conjunction with sensor technology!
Here are some of the components to these sorts of interfaces.................................
Applied for: greeting card, electronic sound toy, Doll , sound gift and hobby etc..
Components: PCB, IC, speaker, microphone, LED indicator, batteries, plastic shell (more or less for different items)
Power : Button cell AG13 AG10, Dry battery AAA , AA.
Messages: voice, music, and sound, customized sounds are available (MP3 or WAV format file )
Function: pre-recorded or recordable, USB input, with LED flash (optional)
Recording duration: 5 seconds to 270 seconds, even more if required
Activated: by pull-tab (slide) switch. light sensor . Infrared sensor. push button. timer (play music automatically at a certain time).vibration sensor (vibrate the module to play music).temperature sensor. voice sensor.