RF would be a far better fit for this application. Either RFID or Bluetooth can work over a short range and could trigger your device to start playing back the relevant field.
A camera system is overkill considering you're in a controlled environment with a limited number of objects.
However some people don't like to take the easy route ... in which case you could use a RaspberryPi with a camera and wifi module. I'd then suggest a RaspberryPi dedicated forum to help you with the code.